Nils, as a follow-up to this video, you should use your manometer to look at using furnace filters with different MERV ratings. There is a lot of advice to not use filters with high MERV ratings also for the reason that it would be too hard for the blower fan. You can use the same set up to look at this issue.
It's perfectly fine to close them. They claim you shouldn't close vents and instead install dampers. Both do the same thing, increase static pressure at the blockage. A blockage is a blockage, doesn't matter how you do it. So why is one ok but not the other? The answer is there is no reason, other than the one they want you to do is expensive. This is nothing but a complete lack of critical thought at best, or an intentional scam at worst
Cold/hot wet air in the duct vs cold/hot wet air in the supply plenum. The duct is not designed to hold moisture/humidity - which will collect dust/dirt and grow mold and bacteria. Come back to this comment when the kid you eventually end up putting in that room has allergies and is sick all the time and nobody else in the house has issues.
@@bryanw4582 Probably why it’s so important to have your ducts downstream of the filter cleaned every 6 months. It’s a dust magnet!😉 I’m guessing you run a duct cleaning service?
I live alone and have 3 extra bedrooms and 2 bathrooms in the house that I never go into. I keep the vents in those rooms closed, along with the doors. I did it in hopes of saving money on heating and cooling. I never knew that experts have thought this was a bad idea, and happy to now also hear they were wrong
That's my concern. If no one is barely in the space, why would someone want a constant air or heat there. I don't close the doors of the areas with less traffic in my almost four years old house.
I had my basement vents closed for 24yrs. Everything worked fine. The HVAC was replaced last summer with modern freon. It is much more efficient with a more powerful blower motor. Maybe in 10 years I'll open the vents if I remember.
I love how you apply the scientific method to all the neighborhood gossip about house maintenance and create a wonderful video out of it. Thank you again LRN2DIY.
Two story house - standard operating procedure - summer vents downstairs closed - winter vents upstairs closed. I live in what’s open in one story is closed in the other.
That's ridiculous. The registers have switches on them intended to open/close them. If closing one of the registers causes a problem then the system is not designed properly.
Closing one or two isn’t a big deal, but closing half of them may make the fan work harder. Even if you close most of them, a fan should last many years and they’re only usually $100-200 to replace… until you get into labor costs.
@@DarthTeaDiousit is so rare for the blower fan to fail. I get maybe one or two a year where the blower fan fails. I've seen the bearings fail because people don't oil them. I've seen the secondary heat exchange covered in dust because they don't change/use filters. Far more likely to throw a limit switch if there isn't enough air flow. Either too many of the vents are closed or an idiot put a rug over one or the only cold air return. Have seen people install furnaces with two or four 6" ducts coming off of the bonnet. Be like that for a decade. If closing off a couple of vents were to destroy a furnace then I'd see a crapload
@@bryanw4582 ya but if there is no air to go down that supply route then it is effectively closed. I don't see how it can be disruptive to the flow of air exiting the plenum
Closing a vent will place pressure all along the line going to it. If you have any leaks in that line it will be exasperated. Closing a damper at the junction will ensure more will go through the other lines and keep pressure out of that line you want closed.
The damper in the register is like a faucet, it controls how fast it replaces the room air. Most HVAC issues are caused by not enough return or returns in bad or poor areas. Don't know why people would say "You can't use the feature the device comes with". Do an update and show the difference in velocity, temp and CFM. It would paint a clearer picture. Good vid.
Most blowers have a max pressure they can develop and often are not bothered running at that stall pressure. The issue to consider is the change in flow across heat exchange or evaporator coil. That can cause the evaporator coil to freeze over. Also, consider where the thermostat is. If you change the heat/cool rate to that sensor, you may cause the system to cycle too often or not enough. Vents can be helpful to balance a system but don’t go crazy.
Glad to see the video. I use my second bedroom for inside storage. I have the vent closed because I am okay if the room is a little colder or a little warmer than the rest of the house.
We have a 1.5 story home, 3 bedrooms up and 1 down, and the upstairs has trouble with heating in the winter and cooling in the summer if all vents are open. What has helped was closing the two vents in our living/great room because the thermostat is in that room. It isn't perfect, but keeps the temperatures even to maybe 2 degrees difference. I didnt' actually close the vents, I closed the dampers which is effectively the same thing. I think I will check my static pressure as a little project.
Been doing that for years...my Trane lasted 25 years. Also, I leave the fan on 24-7 to help keep air flowing/mixing/balance better throughout. Had to replace the blower fan after 15 years...$250. I change filter every 6 weeks. Not sure how adding dampers is any different than closing some registers. meh.....Great vid...so manly too!
I've had a Trane furnace in my basement for over 10 years. I never left my blower running and everytime the furnace kicked on in the winter time my ducts would make banging noises when the air came through until they were warm. I called trane and asked what would cause that and he explained why and told me to run the blower 24/7 and no more banging!! I also noticed the air quality is better in my home! I change my filter monthly as I live out in the country with a dirt road so kicks up alot of dust in summer!! By running the blower 24/7 I've noticed it doesn't get as chilly in the house before the heat kicks on again and it doesn't kick on as often! I agree with the comment above about the air flowing/mixing so a good balance of air flow!!
I just had a whole new HVAC system installed. It's amazing how much BS some companies want to blow up your tail pipe. I had gotten 5 estimates and, they were all across the board$$$ I only had 1 company question the number of cold air returns in the house. If you are a home owner, not knowing your stuff can cost you much grief and money..GREAT VIDEO!...Air balance and static pressures are legit!...pay attention
This summer I had 2 companies give me estimates, with around $2000 difference in price for the same system. I had 1 vent down under the house, and one guy knew it but said I had a bad system. Next guy hooked the vent back up and all was good. Yes, it's good to know your stuff.
I find this and the comments pretty entertaining. You should conduct an interview with the manufacturers and ask them why they build the feature into their product if it is not supposed to be used as well as what their intended use is 😉
feature? You mean stating the static pressure? The idea is to get the rated BTUs from point A to point B. static pressure is part of the calculation when figuring the air flow. (CFM rating)
@@MikeNovelli did you watch the video to the end where he said the myth was busted and closing them didn't make much difference? BTW, those registers are not made by the same company as the furnace so "intended use" can be anything the mfgr wants. It's up to the installer and end user to understand the limits.
@@rupe53 what does any of that have to do with your question about "features?" I'm fully aware of how HVAC systems function. I understand features and benefits of multiple different systems as well as the complete steps to fabricate and install those systems.... Likely far better than you. 🤷🏼♂️
@@MikeNovelli I was also in that business and recently gave up my license for retirement. Your original question didn't spell out what" feature" you were talking about, which is why I worded things the way I did.
Our house was built with a main furnace/AC for the main floor. As is customary here, when we later finished our basement we simply added supply and air returns to that same system for the basement. Occasionally we close two rooms in the basement. The system was designed for, and ran fine with non of the basement vents, so it seems to do just fine.
Worth noting, that in many modern American homes, the duct lines are not anywhere close to sealed. I have a multi-story home on a single unit. And I can confirm that closing one of the floors does help shift how much flow gets to the correct flow for the season that we want it. Any extra "back pressure" is mostly relieved by how "leaky" the lines are through the house. Not a big deal so long as they are within the insulated envelope of your home.
I have a weird, multi-level split home and I recently got a new system (NG heat and central AC through forced air) that has an electronic, thermostat controlled damper for each main trunk, thus four "zones". There's also a bypass damper in case there's just one zone open so that the fan doesn't choke. There's also multiple takeoffs with individual manual dampers to help "balance" rooms within each zone. It took a lot of work to get everything working well, especially for AC since cold air does not like to rise up to the top level of the house.
In the summer I open the vents full on the second floor, halfway open on the first and close to closed in the basement. If I didn't, the basement would be an ice box and the second floor an oven with AC. In the winter, full open in the basement, half open in the first floor,( exception washroom), then upstairs nearly closed, all to keep the house even with the washroom 4 degrees higher. In 95 we replaced the 1960s furnace with a janitrol in order to install central AC. The sixties unit was close to failure, YET THE BLOWER WAS FINE! 5 Years ago we replaced the Janitrol, because the AC unit was shot and new AC units wouldn't be compatible with the Janitrol, that was wearing out, YET WE NEVER NEEDED TO REPLACE THE BLOWER, only a circuit board. I'd assume if there was a problem with static pressure with my vent adjustment, the ducting and or vents aren't sufficient for the blower output. I've heard of ripoff contractors selling overly large furnaces with larger blowers that might need less restrictions by more venting in larger homes. I'm not going to open all my vents, heat or cool my house unevenly, even if it extends the life of the blower from 30 to 35 years, when the furnace usually wears out every 25 to 35 years!
There are so many reasons to support the closing of vents. For example when you are doing the AC. if you leave your vents open downstairs you will freeze out the people who exist down there. By pure physics cold air will settle and the basement will get its fair share of cooler air. If your basement is above ground level then it changes the rules, you want your vents open because you have added heat transfer area. As for closing the upstairs vents in the cooler times, that's a product of comfort level and balance. If it's hot upstairs and just right the next floor down, you might choose to close or at least somewhat restrict upstairs vents. Again it's about balance. In a high balanced system you will want to pay close attention to static pressures. But most homes are not prone to that ultimate requirement, largely because they are not necessarily completely properly designed and balanced to that point. I found a couple things interesting in this video that I am critical of. First, the larger hole in the bottom of the unit by the blower, they should have taped that hole with aluminum or duct tape to better seal around the manometer probe. I don't know how far off the readings were because the air flow was so different because of that hole. Might not make any difference, I don't know. Second, don't close the duct vent covers but balance a system with dampers in the lines? Uhm, that's the same thing only in a different area. I have 2 rooms on my main floor living area My system is not very well balanced. My one side gets all the air and the other 65% of the area gets under done. So I close the vents off in the bathroom and laundry room which are next to the thermostat. It helps balance out the temps much better that way. If you want to freeze in the basement, leave your vents open. If you want to balance out your cooling, just let the cold sink by nature and blow more air upstairs by closing the vents in the basement. Simple as that. Reverse it for heating.
Sometimes codes can dictate where vents must be: Our master bedroom closet is roughly 7'x8', I argued against it, but code required it. Obviously I closed it and the damper, but it is still the warmest room in the house! Someday I am going to remove or fully block it.
I would have thought you would have taken the staic pressure above the a/c unit rather than above the heating core. Winter or summer all the air being pushed is going through the heating chamber amd through the a/c coil. Oir side of that interesting that closing off vents did not make much of a difference. So a lot of air leakage in the joints of the duct work and even the floor vents. even with them close they will still pass air around the joint between supply pipe and the vent. Would a hi velocity system ,the ones with pvc pipes suppling the air ne more effected by closing some vents off.
If it's a floor vent, stack something on top of it. I've tried stuffing rags in ceiling vents, but it doesn't usually work too well. You probably want some air flow in the closet to remove moisture.
@@elhoward7440 It is a baseboard register, so I can probably take it off once I block or remove the duct work from the basement. I wish it was a floor vent, we may be replacing the flooring in the near future and it would be easier than reworking the baseboard and drywall on that wall.
Since my closet was on the 1st floor over the basement, I simply redirected the closet's vent supply duct to a new vent in the basement. Solved 2 problems at once - now a warmer basement that I spend quite a bit of time in, and a cooler walk-in closet that nobody spends time in.
I'm currently living in a friend's house in Southern Texas. He's a retired HVAC residential Installer, so he spent years in extremely hot attics. Consequently he is comfortable at much higher room temps than I am. So I installed a window unit in my room and sealed off the ceiling vent. I removed the existing vent then used scrap plywood piece larger than the vent to mount over it. 1/16 inch closed cell foam glued to the wood provides the seal. No whistle, no air flow. This way my room is fully removed from the whole house system.
In the cooling mode, there needs to be enough air moving across the indoor coil. Closing air vents can affect that. If there isnt enough air moving across, the refrigerant inside might not reach a boiling point, and it will stay in a liquid state. Running liquid back to the compressor outside, can definitely destroy a compressor. It is made to pump vapor and not liquid. I've seen it hundreds of times, but usually from a dirty filter or dirty indoor coil(caused by poor filter maintenance). Closed vents have caused low air flow ruined compressors.
Don’t tell them that. It’s reason me and you have jobs lol. From reading the comments they think whoever manufactured the system also manufactured the vents and shipped them with it.
Probably worth mentioning that the differential pressure between any two points in the system changes with the speed of the blower (which affects flow rate). I think it's a square relationship, but it's been a few years since I studied statics/dynamics. Some systems (like mine) have multi-stage heating and a variable speed blower, designed to change speed in response to the amount of heating or cooling demand. Seems like the impact would be insignificant almost all the time, since the blower tends to operate at a low speed almost all the time (except in cases of a call for extremely high heat or cooling demand).
This makes sense, but I can say first hand that I have had 30% of my vents shut in my home. My furnace lasted 18 years and was still working fine but I put a new setup in preventatively. Never heard a whistle either thankfully. I do want a manometer tho! One tool I don’t have!
I love (sarcasm) how folks who say "never close your vents" talk about installing in line "dampers". We have a basement and every summer / winter have to go around to the registers and open/close them to direct where the HVAC is pumping its hot/cold air. Would really love to have it automated but haven't seen a good solution that doesn't require opening walls/ceilings to run power. One of the HVAC friends I have suggested a mini split but that's a lot of $$$ too.
Love mini splits, but if you already have working central air, definitely not worth the money. I suspect in the future someone will start selling thermostat operated vents, but that would only be for new construction since it would require wiring to every vent... although you could in theory snake wires down the pipes. Trying to hand balance all the vents for even temperature seems like an exercise in frustration.
Very helpful. I'd like to request a related topic for your consideration: optimizing your blower speed. Rich Trethewy from This Old House suggested that the slower the speed the more time the air has in the heat exchanger so it emerges a bit hotter. I set mine on the lowest speed mostly for the quieter operation in my very small house. Thanks for your clear, fat-free and funny videos.
@@rupe53 they're never closed completely. They aren't air tight. There's nothing wrong with closing them. If there is, there's a problem with the system. A fan is such a simple thing that "reducing" the lifespan is a non issue.
@@themonsterunderyourbed9408 let me rephrase that. The key I was posting on was the key point of the video. At the end he said the myth was busted and it really doesn't matter much. BTW, a fan like this actually works LESS with less airflow. The only way to do damage is to reduce the flow to a point where the motor isn't cooling.
@@NewYears1978 ya know, there's some funny stuff in the code books and maybe they were trying to slip one by the inspector when the place was built. It could even be that closet didn't exist at the time. I watched someone get their CO on a place based on 3 bedrooms. There was a 4th room they were calling an office. That office had a small alcove where they said was going to be a bookcase. The difference? A closet makes it a bedroom... and the septic is supposed to be larger with more bedrooms. No closet and it doesn't count as a bedroom. Go get your CO and make a closet later. In your case the actual location of that register may be a goof or may be based on square footage of the room. (for the inspector?)
I closed a vent that splits between the hallway and a bedroom. I don't need the hallway to be heated, so I closed the vent. That solved my problem of my kids' room being cold all the time. ❄️💨
Hey there. Not the same issue but figure this. We have an upstairs bonus room that had 2 vents. It was always 7-10 degrees hotter up there in the summer. Had a minisplit installed and completely removed those 2 vents from the main a/c. Long story short, out a/c bill went.......DOWN! Even though we are now running 2 units instead of one. And the whole house is more comfortable now.
Thanks for the video. I had my bedroom vents closed in the winter for 4 months every year and my system is 30 years old with the original blower. So it doesn't seemed to have shorted the life. Also, I don't understand why dampers wouldn't increase the static pressure just as much as closing the vent.
I have a 2 story house. The 2nd floor is 4 bedrooms and a bathroom. I generally would keep 2 bedroom vents closed because they are spare rooms. However, one thing I noticed is when I did this, the upstairs actually felt colder, even though I was trying to force warmer air to the bedrooms being used. I find it to better heat when all the vents are open (even when closing the doors of the bedrooms not being used). Probably don't have the best insulated house, but just my observation
It all sums up into the acknowledgment that central healing or cooling that does not provide an adjustable regulation for each room is ill conceived. Standard duct air is not a good system. I don't see how a closed damper is different from closing all the vents attached to that section of pipe.
Hi olivier : to your first comment- Yeah the typical central air system is pretty basic, sometimes bad, mostly because its "dumb" ie not reactive to changeing conditions, or "smart". It just does what it was setup to do, with only a single sensor (thermostat) in one location (mostly), and even the so-called smart ones dont fix that. Some of the web connected ones may recieve external data like time, local weather conditions and predictions. Most dont include internal muti-sensors for fine control. I recall an episode of "This Old House" on PBS that featured an engineer home owner that came up with a system of drop-in controllable registers and dampers incorporateing sensors, wireless networked to a central Smart controller that can individually control flow to rooms and replaces the usual thermostat HVAC control. Seems to be an easy "drop in" for retrofits of most existing systems. With a self learning AI, it maybe could be a true "set and forget" system - exept for replaceing or recharging the batteries😊. As for dampers- it probably just moves the turbulent flow noise further away from hearing, while balanceing pressures and flow thru the system. Less likely for the kids/dogs to mess with too.😂
@@KevinSmith-ys3mh Even without full AI, being able to get the bathroom, where you go wet and naked, warmer than the kitchen where you have cooking elements going, should be them minimum implemented. Being French, we only have central heating, no A/C, but with water circulation and pretty much every where a thermostat on the radiators: either the hot water circulate the radiator and warms up the room, or the thermostat shut it off and the water is circulated back to the furnace, in any case, the water is never prevented from running, so there is no problem of static pressure.
I have a storage room that has a vent in it. I use it as a cellar and close the vent in the winter and open it when it gets hot outside and I have the ac on. Has been working great for four years.
If recommended is .5 and it was closer to .6, that’s 20%. Is that within the manufacturer’s specs range? Have they tested? I have many customers complain of cool basements and I so often suggest closing a few vents, but if a few isn’t enough, recommend bringing in an hvac guy to evaluate. I think I’ll still add the caveat, but feel a bit more confident in my recommendation not likely to cause problems. Good tip on checking the return ducts and filters being important. Thanks for the video.
Another option is to install a weighted bypass damper. These reduce static pressure by creating a "short circuit" from return to supply that automatically opens variably as needed.
Hello, I was curious what you would say… Few things can happen if you close too much of them. A/C: the coil can freeze, but for that you will really lower the air flow and the temperature Heating: same, if the air flow is too low, once you run with your aux heat, it can cut on high limit. Personaly, I’m living in an old house. Summer, I close all my register in the basement and in my 2 bathrooms. Their is enough air flow, never got issue Winter, everything is open, never had issue, temperature is +/- 1 degree between basement and 2nd floor.
Dampers are used to balance the house, not shut off a branch. The concern isnt in heating or even the fan motor, the concern is with cooling, the proper test would be to monitor refrigerant pressures and superheat, the concern is the evaporator freezing up and/or sending liquid back to the compressor.
The very first thing to check is how long your blower runs after the system stops heating or cooling. Most system default to the shortest time. let it run longer and it helps a lot with room balancing.
I have the reverse problem--rooms that get sometimes get overly hot in the winter and overly cold in the summer. So I partially or fully close the vents in those rooms as necessary. Never had a problem with it. But most of the vents in the house stay open. I do have one vent though, in the kitchen, that seems to've not been installed quite properly, as even when fully open it barely flows any air. I wish I could open that one more!
Another simple way to help even out hot/cold rooms...keep your inside doors open as much as possible and set your blower to run a minimum of 15-20 mins every hour regardless of temperature. If your thermostat doesn't allow independent fan control get a modern thermostat.
You can get a zone controller with electronic dampers and zone off parts of your house. They add a bypass damper to keep reasonable static pressures when only one area is heating. Could be a good video idea.
You should mention heat exchanger failures. If too many vents are closed, CFM can be reduced, and thus the heat exchanger runs hotter than it should be, and cause premature failure. Same thing for air conditioning...low-side pressure can get to low, and the compressor can even be "slugged" with liquid refrigerant that didn't evaporate in the evaporator coil
The main reason not to close vents is because it lowers the efficiency of heat transfer. With less air passing by the coils, the ability for coils to transfer heat is reduced, which in a worst case situation will cause A/C coils to freeze over. When there is freezing over this causes a cascade of reduced air movement and the system becomes overloaded, staying on for too long each cycle to defrost properly. When cycle duration is increased your power bills go up.
I would say that the insulation property’s of the house and the controls of the hvac system should be checked first before an immediate focus on air balancing I find that whether or not vents are closed. Everything tends to equalize within the house when the air handler shuts off. Homes that have poor insulation might be more sensitive to closed vents. Also different floors have different energy losses or gains based upon the stack effect. So, in a multistory house, regardless of whether or not the vents are closed or not. That floor will retain different energy loss properties will completely change based on outdoor conditions. This might reduce the effectiveness when trying to balance different floors. Also the location of returns also makes a difference. Bedrooms with individual returns will just draw air from somewhere else if that vent is closed. Dampers might make sense so long as they’re closer to the takeoff in the main plenum. This is because energy transfer may be more prevalent than just airflow alone. And in the heating seasons, the residual heat in the ductwork system migrates upstairs through the vents and branch runs. I’m happy to hear other’s opinions/experiences on this topic.
Not related to the Vents question, but since you mentioned your water heater: The original home owner installed a Rheem in my home which started to leak about one year after installation. Apparently they have a problem with their plastic drain ports, if your Rheem has a plastic drain port (typically grey plastic) make sure you're regularly checking the base of the unit for water build up. I exercised my warranty and replaced it with a Noritz Tankless as my parents have had two for 15 years that have only ever had an igniter issue which I fixed by replacing the igniter for $10.
I have a 1 floor house 3 bedrooms with 6 vents. There are 1 vent in each room and the other 3 vents are in the kitchen, living room, and dining room this part of the house is almost half of the house and has 1 wall with an open window square hole with a door hole as there is not a door there. I closed these 3 vents and blocked it with some old under shirts and stapled some painters plastic to keep any air from moving through. There is a hallway that runs the middle of the house and I hung the painters plastic at the beginning of the hallway and stapled it to the ceiling and walls and cut a slit from the bottom to just high enough to crouch under. My electric bill went from $300 to $75 for the summer months in Dallas Texas. The bed rooms stay as cold as I want and the HVAC is in the hallway, July temps 90-105, living room temp 80-90 depending on out side temps. one of the bedrooms turned into the new living room to watch tv and cooking wasn't that bad knowing I was saving money, I can now afford real meat instead of eating Vienna sausage
It would be pretty idiotic to design a system that operates at the limit of static pressure and then include vents that can only increase that pressure. 😅
CFM across your heat exchanger and evaporator are important not enough CFM and you can over heat your heat exchanger or freeze (ice over) your evaporator
Yes sir make sure your temp rise is in range for heating and 400cfm per ton for a/c. Closing vents can definitely affect these readings. Every system is different. No myth was busted here. Just your usual you tube misinformation.
The work for a water pump or fan is MOVING their workload. For the fan, it's air, for the water pump, it's water. When you restrict the flow on either one, you limit their work. You can easily see this with an amp meter. The more you limit the flow, the lower the amps go. Restricting the flow completely creates a free spin on the water or air mover. It's funny that while you are doing this, the outlet pressure will rise. This makes many think the pump is working harder, this makes many easy targets for my bet with the amp meter that is showing the actual workload. A good argument for not closing the vents could be that if they are restricted too much, during the cooling cycle the cooling coil could freeze. Personally, when the water is too hot I turn down or restrict the hot water, and the same if it's too cold, adjust the two to get the desired temp. Many have learned a great amount in our day and age some have not and burn themselves.
What would be helpful is measuring the blower motor current before and after closing the vents. The rated current of the blower will show if it is overloaded and the additional power loss can be calculated.
Even if the static pressure had increased a lot, it would not result in the blower working harder. Its counterintuitive but it would actually be lowering the load. You could verify this by measuring the current draw, which would decrease. A good example is your vacuum cleaner; if you put your hand on the end of the hose the, motor speed increases. That's because instead of having to accelerate new air coming in and expel it, it just has to keep the same air spinning around in the blower housing.
true, but in the case of a vacuum (or heating system) the motor depends on that moving air for its cooling. Block that too much and the motor will overheat.
@@nlkatz you raise a valid point as many up-right vacs are not the flow-through type. OTOH, most canister and shop vacs depend on the air flow. On those you can block the hose and hear the motor change pitch.
That only applies to a PSC blower motor which slows down without a load. An ECM motor which is pretty standard all high efficiency systems will push harder and the amperage load will increase dramatically, putting strain on the motor. They push through the restriction no matter what you do. A vacuum cleaner is a far cry from an HVAC system.
@@Balticblue93 My original point stands regardless of the motor type; restricting the inlet or outlet of a centrifugal fan/blower/pump reduces the load on the drive motor.
Last year I had a burnt smell when the furnace was on. Had a HVAC guy come in and two hours later he blamed multiple closed vents. He said the system was burning adequately due to vents being closed. After they were opened the flame burned blue "like it should" and the burnt smell was gone. That was a $290 visit and now I only close one vent.
Exactly because you need a certain amount of cfm to pass through depending on size of unit. This guy doesn’t realize a person can look perfectly healthy on the outside but is actually very sick on the inside. 🤯
The problem is that forced air heating is a sucky system since you only have one thermostat. So you have to close off vents to keep the temperature right in certain rooms.
It’s just manual zone damping. I do this seasonally between the basement and main level. Air will operate like water choosing the path of lest resistance. The testing part of this perfectly explains why it’s no big deal.
Never search for this topic or even said it out loud near a smart device. Yet 30 minutes after closing a vent in my house I get this on my top feed. God help us, we truly are in a fishbowl. 😳
I would think measuring the amperage the motor is pulling would also be a good data point to look at. Does that tenth increase, equal a substantial increase in load on the blower motor. Additionally what about different style systems. Ours doesn't have a fresh air feed and runs on cold air returns. What's the difference in starting pressure on a house that has a negative pressure system.
May be related to other problems, like mold in places whre you have no heating/ventilation. Kids and old prople are more likely to have problems (asthma, allergies etc.).
Closing the vents on your furnace can definitely cause a problem if your ducts aren't installed correctly I can tell you that for a fact. Whoever installed the duct work in my house didn't do it correctly and most of the air comes out in back end my house, 2 bedrooms and a bathroom. I shut the vents in the bedrooms thinking the heat would be redirected to the other areas of the house and this caused my furnace to over heat and it tripped the flame roll out switch. Fortunately no damage was done and I learned not to close my registers.
In the winter the upstairs vents are closed, in the summer the downstairs are close. That's the only way the house temperatures are tolerable. Glad the test says it's OK because I was going to continue to do it regardless.
This doesn't surprise me... we had new vent work done (L shaped rambler, heater is in the basement roughly in the point of the L) and after that a vent in the floor of a bathroom directly above the heater was getting blasted by heat or cold, and registers on the far ends of the L were basically not blowing. Blocked off the vent into that bathroom and poof - air coming out of the far registers again. Seemed like pretty basic physics - that register directly above the heater was the path of least resistance so most of the blown air was coming straight out of that instead of pushing all that extra air through the vents to reach the registers at the far ends of the L shape of the house. By blocking the "direct easy" path, air pressure had no choice but to go through the rest of the system.
I have a couple vents closed in rooms we dont use to try and get more air to rooms that are not well served. Been like that for 30 years and same furnace motor.
I have one vent permanently closed (it was blowing towards the t-stat some 10 feet away). Same vent was in the line going to the 2nd floor. 2nd floor now has a bit better A/C and heat. Dirty air filter can cost you a LOT..... So can dirty evaporator coils.
To calculate the pressure drop between the blower cavity and the heater cavity, shouldn't you subtract their respective static pressures, not add them?
@@bryanw4582forgive me, perhaps I did not phrase my comment correctly. Why not just have mesh vents that are not closeable. Would save cost and complexity.
Hopefully none of your ducts have leaks or holes in them. We need an update with the ducts inspected. So maybe that's why the pressure didn't change as much. Good video
HVAC technicians say DO NOT CLOSE OFF VENTS and yet they install dampers which essentially DO THE SAME THING. All they want is the service call money to check out the system and recommend installing dampers, which DO THE SAME THING.
I don't know what a normal range is, but if the static pressure changes that little even after closing all vents, that suggests to me that there are some major leaks somewhere in the airflow because the air is still able to find pressure relief somewhere pretty easily. Is that possible?
Nils, as a follow-up to this video, you should use your manometer to look at using furnace filters with different MERV ratings. There is a lot of advice to not use filters with high MERV ratings also for the reason that it would be too hard for the blower fan. You can use the same set up to look at this issue.
It's perfectly fine to close them. They claim you shouldn't close vents and instead install dampers. Both do the same thing, increase static pressure at the blockage. A blockage is a blockage, doesn't matter how you do it. So why is one ok but not the other? The answer is there is no reason, other than the one they want you to do is expensive. This is nothing but a complete lack of critical thought at best, or an intentional scam at worst
Cold/hot wet air in the duct vs cold/hot wet air in the supply plenum. The duct is not designed to hold moisture/humidity - which will collect dust/dirt and grow mold and bacteria. Come back to this comment when the kid you eventually end up putting in that room has allergies and is sick all the time and nobody else in the house has issues.
@@bryanw4582 Probably why it’s so important to have your ducts downstream of the filter cleaned every 6 months. It’s a dust magnet!😉 I’m guessing you run a duct cleaning service?
I was just going to point that out.
@@joefrommontana252no, I have a kid with terrible food allergies, likely from negligent HVAC installers
@@joefrommontana252Unless the duct is metal, cleaning them can destroy the fiberglass and weaken the joints.
I live alone and have 3 extra bedrooms and 2 bathrooms in the house that I never go into. I keep the vents in those rooms closed, along with the doors. I did it in hopes of saving money on heating and cooling. I never knew that experts have thought this was a bad idea, and happy to now also hear they were wrong
That's my concern. If no one is barely in the space, why would someone want a constant air or heat there. I don't close the doors of the areas with less traffic in my almost four years old house.
I had my basement vents closed for 24yrs. Everything worked fine. The HVAC was replaced last summer with modern freon. It is much more efficient with a more powerful blower motor. Maybe in 10 years I'll open the vents if I remember.
same. they open n' close for a reason.
If you can remember what????
@@steveolive9991 "Maybe in 10 years I'll open the vents if I remember."
Have been doing it for 13 years without any issues. Very glad you busted that myth with evidence.
No myth, keep shutting them off.
It just shows that a lot people say things before they figure out the facts.
I love how you apply the scientific method to all the neighborhood gossip about house maintenance and create a wonderful video out of it. Thank you again LRN2DIY.
Two story house - standard operating procedure - summer vents downstairs closed - winter vents upstairs closed. I live in what’s open in one story is closed in the other.
That's ridiculous. The registers have switches on them intended to open/close them. If closing one of the registers causes a problem then the system is not designed properly.
Watch the whole video
Closing one or two isn’t a big deal, but closing half of them may make the fan work harder. Even if you close most of them, a fan should last many years and they’re only usually $100-200 to replace… until you get into labor costs.
Ask yourself why they don’t fully seal the vent? The switch is to redirect the air, not close it
@@DarthTeaDiousit is so rare for the blower fan to fail. I get maybe one or two a year where the blower fan fails.
I've seen the bearings fail because people don't oil them. I've seen the secondary heat exchange covered in dust because they don't change/use filters.
Far more likely to throw a limit switch if there isn't enough air flow. Either too many of the vents are closed or an idiot put a rug over one or the only cold air return.
Have seen people install furnaces with two or four 6" ducts coming off of the bonnet.
Be like that for a decade.
If closing off a couple of vents were to destroy a furnace then I'd see a crapload
It's not a problem, this video concluded the myth is busted.
How does a damper differ from just closing all the vents that duct is connected to?
Dampers are meant to go at the supply plenum
@@bryanw4582 ya but if there is no air to go down that supply route then it is effectively closed. I don't see how it can be disruptive to the flow of air exiting the plenum
Closing a vent will place pressure all along the line going to it. If you have any leaks in that line it will be exasperated. Closing a damper at the junction will ensure more will go through the other lines and keep pressure out of that line you want closed.
$$$
@@psedog but how does a damper miraculously not increase static pressure on the blower?
The damper in the register is like a faucet, it controls how fast it replaces the room air. Most HVAC issues are caused by not enough return or returns in bad or poor areas.
Don't know why people would say "You can't use the feature the device comes with". Do an update and show the difference in velocity, temp and CFM. It would paint a clearer picture. Good vid.
Most blowers have a max pressure they can develop and often are not bothered running at that stall pressure. The issue to consider is the change in flow across heat exchange or evaporator coil. That can cause the evaporator coil to freeze over. Also, consider where the thermostat is. If you change the heat/cool rate to that sensor, you may cause the system to cycle too often or not enough. Vents can be helpful to balance a system but don’t go crazy.
Glad to see the video. I use my second bedroom for inside storage. I have the vent closed because I am okay if the room is a little colder or a little warmer than the rest of the house.
You can also check running current on the blower fan motor as you close the vents. If not loaded near FLA then okay.
If you increase back pressure, amperage will go down on a centrifugal blower
@@nspro931exactly, and if you open the panel while it’s running, it will increase a lot, and most of the time way more than the RLA
We have a 1.5 story home, 3 bedrooms up and 1 down, and the upstairs has trouble with heating in the winter and cooling in the summer if all vents are open. What has helped was closing the two vents in our living/great room because the thermostat is in that room. It isn't perfect, but keeps the temperatures even to maybe 2 degrees difference. I didnt' actually close the vents, I closed the dampers which is effectively the same thing. I think I will check my static pressure as a little project.
Been doing that for years...my Trane lasted 25 years. Also, I leave the fan on 24-7 to help keep air flowing/mixing/balance better throughout. Had to replace the blower fan after 15 years...$250. I change filter every 6 weeks. Not sure how adding dampers is any different than closing some registers. meh.....Great vid...so manly too!
My Trane is presently 17 years old, runs just fine.
I've had a Trane furnace in my basement for over 10 years. I never left my blower running and everytime the furnace kicked on in the winter time my ducts would make banging noises when the air came through until they were warm. I called trane and asked what would cause that and he explained why and told me to run the blower 24/7 and no more banging!! I also noticed the air quality is better in my home! I change my filter monthly as I live out in the country with a dirt road so kicks up alot of dust in summer!! By running the blower 24/7 I've noticed it doesn't get as chilly in the house before the heat kicks on again and it doesn't kick on as often! I agree with the comment above about the air flowing/mixing so a good balance of air flow!!
I just had a whole new HVAC system installed. It's amazing how much BS some companies want to blow up your tail pipe. I had gotten 5 estimates and, they were all across the board$$$ I only had 1 company question the number of cold air returns in the house. If you are a home owner, not knowing your stuff can cost you much grief and money..GREAT VIDEO!...Air balance and static pressures are legit!...pay attention
This summer I had 2 companies give me estimates, with around $2000 difference in price for the same system. I had 1 vent down under the house, and one guy knew it but said I had a bad system. Next guy hooked the vent back up and all was good. Yes, it's good to know your stuff.
I find this and the comments pretty entertaining.
You should conduct an interview with the manufacturers and ask them why they build the feature into their product if it is not supposed to be used as well as what their intended use is 😉
feature? You mean stating the static pressure? The idea is to get the rated BTUs from point A to point B. static pressure is part of the calculation when figuring the air flow. (CFM rating)
@rupe53 the feature is the swiveling slats..what don't you comprehend?
@@MikeNovelli did you watch the video to the end where he said the myth was busted and closing them didn't make much difference? BTW, those registers are not made by the same company as the furnace so "intended use" can be anything the mfgr wants. It's up to the installer and end user to understand the limits.
@@rupe53 what does any of that have to do with your question about "features?"
I'm fully aware of how HVAC systems function. I understand features and benefits of multiple different systems as well as the complete steps to fabricate and install those systems.... Likely far better than you. 🤷🏼♂️
@@MikeNovelli I was also in that business and recently gave up my license for retirement. Your original question didn't spell out what" feature" you were talking about, which is why I worded things the way I did.
Our house was built with a main furnace/AC for the main floor. As is customary here, when we later finished our basement we simply added supply and air returns to that same system for the basement. Occasionally we close two rooms in the basement. The system was designed for, and ran fine with non of the basement vents, so it seems to do just fine.
Worth noting, that in many modern American homes, the duct lines are not anywhere close to sealed. I have a multi-story home on a single unit. And I can confirm that closing one of the floors does help shift how much flow gets to the correct flow for the season that we want it. Any extra "back pressure" is mostly relieved by how "leaky" the lines are through the house. Not a big deal so long as they are within the insulated envelope of your home.
I have a weird, multi-level split home and I recently got a new system (NG heat and central AC through forced air) that has an electronic, thermostat controlled damper for each main trunk, thus four "zones". There's also a bypass damper in case there's just one zone open so that the fan doesn't choke. There's also multiple takeoffs with individual manual dampers to help "balance" rooms within each zone. It took a lot of work to get everything working well, especially for AC since cold air does not like to rise up to the top level of the house.
In the summer I open the vents full on the second floor, halfway open on the first and close to closed in the basement.
If I didn't, the basement would be an ice box and the second floor an oven with AC.
In the winter, full open in the basement, half open in the first floor,( exception washroom), then upstairs nearly closed, all to keep the house even with the washroom 4 degrees higher.
In 95 we replaced the 1960s furnace with a janitrol in order to install central AC.
The sixties unit was close to failure, YET THE BLOWER WAS FINE!
5 Years ago we replaced the Janitrol, because the AC unit was shot and new AC units wouldn't be compatible with the Janitrol, that was wearing out, YET WE NEVER NEEDED TO REPLACE THE BLOWER, only a circuit board.
I'd assume if there was a problem with static pressure with my vent adjustment, the ducting and or vents aren't sufficient for the blower output.
I've heard of ripoff contractors selling overly large furnaces with larger blowers that might need less restrictions by more venting in larger homes.
I'm not going to open all my vents, heat or cool my house unevenly, even if it extends the life of the blower from 30 to 35 years, when the furnace usually wears out every 25 to 35 years!
There are so many reasons to support the closing of vents. For example when you are doing the AC. if you leave your vents open downstairs you will freeze out the people who exist down there. By pure physics cold air will settle and the basement will get its fair share of cooler air. If your basement is above ground level then it changes the rules, you want your vents open because you have added heat transfer area. As for closing the upstairs vents in the cooler times, that's a product of comfort level and balance. If it's hot upstairs and just right the next floor down, you might choose to close or at least somewhat restrict upstairs vents. Again it's about balance.
In a high balanced system you will want to pay close attention to static pressures. But most homes are not prone to that ultimate requirement, largely because they are not necessarily completely properly designed and balanced to that point.
I found a couple things interesting in this video that I am critical of. First, the larger hole in the bottom of the unit by the blower, they should have taped that hole with aluminum or duct tape to better seal around the manometer probe. I don't know how far off the readings were because the air flow was so different because of that hole. Might not make any difference, I don't know. Second, don't close the duct vent covers but balance a system with dampers in the lines? Uhm, that's the same thing only in a different area.
I have 2 rooms on my main floor living area My system is not very well balanced. My one side gets all the air and the other 65% of the area gets under done. So I close the vents off in the bathroom and laundry room which are next to the thermostat. It helps balance out the temps much better that way.
If you want to freeze in the basement, leave your vents open. If you want to balance out your cooling, just let the cold sink by nature and blow more air upstairs by closing the vents in the basement. Simple as that. Reverse it for heating.
Sometimes codes can dictate where vents must be: Our master bedroom closet is roughly 7'x8', I argued against it, but code required it. Obviously I closed it and the damper, but it is still the warmest room in the house! Someday I am going to remove or fully block it.
I would have thought you would have taken the staic pressure above the a/c unit rather than above the heating core.
Winter or summer all the air being pushed is going through the heating chamber amd through the a/c coil.
Oir side of that interesting that closing off vents did not make much of a difference.
So a lot of air leakage in the joints of the duct work and even the floor vents. even with them close they will still pass air around the joint between supply pipe and the vent.
Would a hi velocity system ,the ones with pvc pipes suppling the air ne more effected by closing some vents off.
If it's a floor vent, stack something on top of it. I've tried stuffing rags in ceiling vents, but it doesn't usually work too well. You probably want some air flow in the closet to remove moisture.
@@elhoward7440 It is a baseboard register, so I can probably take it off once I block or remove the duct work from the basement. I wish it was a floor vent, we may be replacing the flooring in the near future and it would be easier than reworking the baseboard and drywall on that wall.
Since my closet was on the 1st floor over the basement, I simply redirected the closet's vent supply duct to a new vent in the basement. Solved 2 problems at once - now a warmer basement that I spend quite a bit of time in, and a cooler walk-in closet that nobody spends time in.
I pulled the cover and taped it closed.
Hummm I've done thus for years. Alot of air was redirected upstairs
I've been doing it for 30 years now never had my house blow up 🤷🏽♂️
Aren't dampers also going to increase the static pressure the same as closing vents?
Well, duh!
I'm currently living in a friend's house in Southern Texas. He's a retired HVAC residential Installer, so he spent years in extremely hot attics. Consequently he is comfortable at much higher room temps than I am.
So I installed a window unit in my room and sealed off the ceiling vent. I removed the existing vent then used scrap plywood piece larger than the vent to mount over it. 1/16 inch closed cell foam glued to the wood provides the seal. No whistle, no air flow. This way my room is fully removed from the whole house system.
In the cooling mode, there needs to be enough air moving across the indoor coil. Closing air vents can affect that. If there isnt enough air moving across, the refrigerant inside might not reach a boiling point, and it will stay in a liquid state. Running liquid back to the compressor outside, can definitely destroy a compressor. It is made to pump vapor and not liquid. I've seen it hundreds of times, but usually from a dirty filter or dirty indoor coil(caused by poor filter maintenance). Closed vents have caused low air flow ruined compressors.
Don’t tell them that. It’s reason me and you have jobs lol. From reading the comments they think whoever manufactured the system also manufactured the vents and shipped them with it.
@craigbates2095 Job security for HVAC guys. Sorry, but I couldn't help but explain.
Probably worth mentioning that the differential pressure between any two points in the system changes with the speed of the blower (which affects flow rate). I think it's a square relationship, but it's been a few years since I studied statics/dynamics. Some systems (like mine) have multi-stage heating and a variable speed blower, designed to change speed in response to the amount of heating or cooling demand. Seems like the impact would be insignificant almost all the time, since the blower tends to operate at a low speed almost all the time (except in cases of a call for extremely high heat or cooling demand).
This makes sense, but I can say first hand that I have had 30% of my vents shut in my home. My furnace lasted 18 years and was still working fine but I put a new setup in preventatively. Never heard a whistle either thankfully. I do want a manometer tho! One tool I don’t have!
I love (sarcasm) how folks who say "never close your vents" talk about installing in line "dampers". We have a basement and every summer / winter have to go around to the registers and open/close them to direct where the HVAC is pumping its hot/cold air. Would really love to have it automated but haven't seen a good solution that doesn't require opening walls/ceilings to run power. One of the HVAC friends I have suggested a mini split but that's a lot of $$$ too.
Love mini splits, but if you already have working central air, definitely not worth the money. I suspect in the future someone will start selling thermostat operated vents, but that would only be for new construction since it would require wiring to every vent... although you could in theory snake wires down the pipes. Trying to hand balance all the vents for even temperature seems like an exercise in frustration.
Very helpful. I'd like to request a related topic for your consideration: optimizing your blower speed. Rich Trethewy from This Old House suggested that the slower the speed the more time the air has in the heat exchanger so it emerges a bit hotter. I set mine on the lowest speed mostly for the quieter operation in my very small house. Thanks for your clear, fat-free and funny videos.
and...if we're not allowed to close off vents....then why do they have dampers installed?
I have a great question. If you're not supposed to close them, why do they close?
The key here is not closing them completely. If the system is designed correctly that will never need to be done.
@@rupe53 they're never closed completely. They aren't air tight.
There's nothing wrong with closing them. If there is, there's a problem with the system. A fan is such a simple thing that "reducing" the lifespan is a non issue.
@@themonsterunderyourbed9408 let me rephrase that. The key I was posting on was the key point of the video. At the end he said the myth was busted and it really doesn't matter much. BTW, a fan like this actually works LESS with less airflow. The only way to do damage is to reduce the flow to a point where the motor isn't cooling.
@@rupe53 Yeah I close some in my house because they put them in my closet..which is not a walk in...kinda silly lol.
@@NewYears1978 ya know, there's some funny stuff in the code books and maybe they were trying to slip one by the inspector when the place was built. It could even be that closet didn't exist at the time. I watched someone get their CO on a place based on 3 bedrooms. There was a 4th room they were calling an office. That office had a small alcove where they said was going to be a bookcase. The difference? A closet makes it a bedroom... and the septic is supposed to be larger with more bedrooms. No closet and it doesn't count as a bedroom. Go get your CO and make a closet later. In your case the actual location of that register may be a goof or may be based on square footage of the room. (for the inspector?)
3:20 how does a damper not also create static pressure? Isn’t the louvers in the floor/ceiling vent essentially an end run damper?
it does change the pressure, but any noise / whistling will be farther away from that room so you won't hear it.
I closed a vent that splits between the hallway and a bedroom. I don't need the hallway to be heated, so I closed the vent. That solved my problem of my kids' room being cold all the time. ❄️💨
Hey there. Not the same issue but figure this. We have an upstairs bonus room that had 2 vents. It was always 7-10 degrees hotter up there in the summer. Had a minisplit installed and completely removed those 2 vents from the main a/c. Long story short, out a/c bill went.......DOWN! Even though we are now running 2 units instead of one. And the whole house is more comfortable now.
Love the statement on the guy's shirt!
Thanks for the video. I had my bedroom vents closed in the winter for 4 months every year and my system is 30 years old with the original blower. So it doesn't seemed to have shorted the life. Also, I don't understand why dampers wouldn't increase the static pressure just as much as closing the vent.
I have a 2 story house. The 2nd floor is 4 bedrooms and a bathroom. I generally would keep 2 bedroom vents closed because they are spare rooms. However, one thing I noticed is when I did this, the upstairs actually felt colder, even though I was trying to force warmer air to the bedrooms being used. I find it to better heat when all the vents are open (even when closing the doors of the bedrooms not being used). Probably don't have the best insulated house, but just my observation
Interior walls are usually not insulated so my guess would be that the unheated rooms are making the walls cold in the rooms that your trying to heat.
Man-o-meter was gold :)
I loved the whistling bit!
I've always blocked off vents, never had whistling, never had to replace a blower in my fifty years of owning homes.
It all sums up into the acknowledgment that central healing or cooling that does not provide an adjustable regulation for each room is ill conceived. Standard duct air is not a good system.
I don't see how a closed damper is different from closing all the vents attached to that section of pipe.
Hi olivier : to your first comment- Yeah the typical central air system is pretty basic, sometimes bad, mostly because its "dumb" ie not reactive to changeing conditions, or "smart". It just does what it was setup to do, with only a single sensor (thermostat) in one location (mostly), and even the so-called smart ones dont fix that. Some of the web connected ones may recieve external data like time, local weather conditions and predictions. Most dont include internal muti-sensors for fine control. I recall an episode of "This Old House" on PBS that featured an engineer home owner that came up with a system of drop-in controllable registers and dampers incorporateing sensors, wireless networked to a central Smart controller that can individually control flow to rooms and replaces the usual thermostat HVAC control. Seems to be an easy "drop in" for retrofits of most existing systems. With a self learning AI, it maybe could be a true "set and forget" system - exept for replaceing or recharging the batteries😊.
As for dampers- it probably just moves the turbulent flow noise further away from hearing, while balanceing pressures and flow thru the system. Less likely for the kids/dogs to mess with too.😂
@@KevinSmith-ys3mh Even without full AI, being able to get the bathroom, where you go wet and naked, warmer than the kitchen where you have cooking elements going, should be them minimum implemented.
Being French, we only have central heating, no A/C, but with water circulation and pretty much every where a thermostat on the radiators: either the hot water circulate the radiator and warms up the room, or the thermostat shut it off and the water is circulated back to the furnace, in any case, the water is never prevented from running, so there is no problem of static pressure.
Installing almost HEPA level filters has to be more work on the blower than closing a few vents.
It is on older systems, filters are not big enough and cannot move enough air throughout system. Newer installs use larger air filters
I have a storage room that has a vent in it. I use it as a cellar and close the vent in the winter and open it when it gets hot outside and I have the ac on. Has been working great for four years.
If recommended is .5 and it was closer to .6, that’s 20%. Is that within the manufacturer’s specs range? Have they tested?
I have many customers complain of cool basements and I so often suggest closing a few vents, but if a few isn’t enough, recommend bringing in an hvac guy to evaluate.
I think I’ll still add the caveat, but feel a bit more confident in my recommendation not likely to cause problems. Good tip on checking the return ducts and filters being important. Thanks for the video.
You can buy temperature adjusted vents and I’ve heard they work great.
Another option is to install a weighted bypass damper. These reduce static pressure by creating a "short circuit" from return to supply that automatically opens variably as needed.
Hello, I was curious what you would say…
Few things can happen if you close too much of them.
A/C: the coil can freeze, but for that you will really lower the air flow and the temperature
Heating: same, if the air flow is too low, once you run with your aux heat, it can cut on high limit.
Personaly, I’m living in an old house.
Summer, I close all my register in the basement and in my 2 bathrooms. Their is enough air flow, never got issue
Winter, everything is open, never had issue, temperature is +/- 1 degree between basement and 2nd floor.
Dampers are used to balance the house, not shut off a branch. The concern isnt in heating or even the fan motor, the concern is with cooling, the proper test would be to monitor refrigerant pressures and superheat, the concern is the evaporator freezing up and/or sending liquid back to the compressor.
The very first thing to check is how long your blower runs after the system stops heating or cooling. Most system default to the shortest time. let it run longer and it helps a lot with room balancing.
I have the reverse problem--rooms that get sometimes get overly hot in the winter and overly cold in the summer. So I partially or fully close the vents in those rooms as necessary. Never had a problem with it. But most of the vents in the house stay open.
I do have one vent though, in the kitchen, that seems to've not been installed quite properly, as even when fully open it barely flows any air. I wish I could open that one more!
Another simple way to help even out hot/cold rooms...keep your inside doors open as much as possible and set your blower to run a minimum of 15-20 mins every hour regardless of temperature. If your thermostat doesn't allow independent fan control get a modern thermostat.
You can get a zone controller with electronic dampers and zone off parts of your house. They add a bypass damper to keep reasonable static pressures when only one area is heating. Could be a good video idea.
You should mention heat exchanger failures. If too many vents are closed, CFM can be reduced, and thus the heat exchanger runs hotter than it should be, and cause premature failure. Same thing for air conditioning...low-side pressure can get to low, and the compressor can even be "slugged" with liquid refrigerant that didn't evaporate in the evaporator coil
The main reason not to close vents is because it lowers the efficiency of heat transfer. With less air passing by the coils, the ability for coils to transfer heat is reduced, which in a worst case situation will cause A/C coils to freeze over. When there is freezing over this causes a cascade of reduced air movement and the system becomes overloaded, staying on for too long each cycle to defrost properly. When cycle duration is increased your power bills go up.
I would say that the insulation property’s of the house and the controls of the hvac system should be checked first before an immediate focus on air balancing
I find that whether or not vents are closed. Everything tends to equalize within the house when the air handler shuts off. Homes that have poor insulation might be more sensitive to closed vents. Also different floors have different energy losses or gains based upon the stack effect. So, in a multistory house, regardless of whether or not the vents are closed or not. That floor will retain different energy loss properties will completely change based on outdoor conditions. This might reduce the effectiveness when trying to balance different floors. Also the location of returns also makes a difference. Bedrooms with individual returns will just draw air from somewhere else if that vent is closed. Dampers might make sense so long as they’re closer to the takeoff in the main plenum. This is because energy transfer may be more prevalent than just airflow alone. And in the heating seasons, the residual heat in the ductwork system migrates upstairs through the vents and branch runs. I’m happy to hear other’s opinions/experiences on this topic.
Not related to the Vents question, but since you mentioned your water heater: The original home owner installed a Rheem in my home which started to leak about one year after installation. Apparently they have a problem with their plastic drain ports, if your Rheem has a plastic drain port (typically grey plastic) make sure you're regularly checking the base of the unit for water build up. I exercised my warranty and replaced it with a Noritz Tankless as my parents have had two for 15 years that have only ever had an igniter issue which I fixed by replacing the igniter for $10.
Thanks, Nils! Yeah, I kind of thought this would be the case. Have a good Thanksgiving!
I have a 1 floor house 3 bedrooms with 6 vents. There are 1 vent in each room and the other 3 vents are in the kitchen, living room, and dining room this part of the house is almost half of the house and has 1 wall with an open window square hole with a door hole as there is not a door there.
I closed these 3 vents and blocked it with some old under shirts and stapled some painters plastic to keep any air from moving through. There is a hallway that runs the middle of the house and I hung the painters plastic at the beginning of the hallway and stapled it to the ceiling and walls and cut a slit from the bottom to just high enough to crouch under.
My electric bill went from $300 to $75 for the summer months in Dallas Texas.
The bed rooms stay as cold as I want and the HVAC is in the hallway, July temps 90-105, living room temp 80-90 depending on out side temps. one of the bedrooms turned into the new living room to watch tv and cooking wasn't that bad knowing I was saving money, I can now afford real meat instead of eating Vienna sausage
It would be pretty idiotic to design a system that operates at the limit of static pressure and then include vents that can only increase that pressure. 😅
CFM across your heat exchanger and evaporator are important not enough CFM and you can over heat your heat exchanger or freeze (ice over) your evaporator
Exactly
Yes sir make sure your temp rise is in range for heating and 400cfm per ton for a/c.
Closing vents can definitely affect these readings. Every system is different. No myth was busted here. Just your usual you tube misinformation.
@@MK-xl9tt lmao thank you 🫡
Very informative . Thank you!
The work for a water pump or fan is MOVING their workload. For the fan, it's air, for the water pump, it's water. When you restrict the flow on either one, you limit their work. You can easily see this with an amp meter. The more you limit the flow, the lower the amps go. Restricting the flow completely creates a free spin on the water or air mover. It's funny that while you are doing this, the outlet pressure will rise. This makes many think the pump is working harder, this makes many easy targets for my bet with the amp meter that is showing the actual workload.
A good argument for not closing the vents could be that if they are restricted too much, during the cooling cycle the cooling coil could freeze. Personally, when the water is too hot I turn down or restrict the hot water, and the same if it's too cold, adjust the two to get the desired temp. Many have learned a great amount in our day and age some have not and burn themselves.
What would be helpful is measuring the blower motor current before and after closing the vents. The rated current of the blower will show if it is overloaded and the additional power loss can be calculated.
I've always enjoyed your content but tell your kiddo that I'm really enjoying the clips and sound effects he's brought to the table.
Great video! I came across this channel and learned a lot. I will subscribe.
Even if the static pressure had increased a lot, it would not result in the blower working harder.
Its counterintuitive but it would actually be lowering the load.
You could verify this by measuring the current draw, which would decrease.
A good example is your vacuum cleaner; if you put your hand on the end of the hose the, motor speed increases.
That's because instead of having to accelerate new air coming in and expel it, it just has to keep the same air spinning around in the blower housing.
true, but in the case of a vacuum (or heating system) the motor depends on that moving air for its cooling. Block that too much and the motor will overheat.
@@rupe53 Also true, but that depends on whether the vacuum motor is a thru-flow or a bypass type; the former would overheat if the airflow is blocked
@@nlkatz you raise a valid point as many up-right vacs are not the flow-through type. OTOH, most canister and shop vacs depend on the air flow. On those you can block the hose and hear the motor change pitch.
That only applies to a PSC blower motor which slows down without a load. An ECM motor which is pretty standard all high efficiency systems will push harder and the amperage load will increase dramatically, putting strain on the motor. They push through the restriction no matter what you do. A vacuum cleaner is a far cry from an HVAC system.
@@Balticblue93 My original point stands regardless of the motor type; restricting the inlet or outlet of a centrifugal fan/blower/pump reduces the load on the drive motor.
As a P.Eng. I would say it is ok. It is like a pumping system, valves close and open.
Last year I had a burnt smell when the furnace was on. Had a HVAC guy come in and two hours later he blamed multiple closed vents. He said the system was burning adequately due to vents being closed. After they were opened the flame burned blue "like it should" and the burnt smell was gone. That was a $290 visit and now I only close one vent.
Dude! That haircut just gets better after each cut. Good barber.
If we close too many vents in our house, the coil will eventually freeze up which really sucks.
Exactly because you need a certain amount of cfm to pass through depending on size of unit.
This guy doesn’t realize a person can look perfectly healthy on the outside but is actually very sick on the inside. 🤯
Love the shirt! Great choice in your water heater as well!!!!
Does using a higher MERV air filter also increase static pressure?
The problem is that forced air heating is a sucky system since you only have one thermostat. So you have to close off vents to keep the temperature right in certain rooms.
It’s just manual zone damping.
I do this seasonally between the basement and main level.
Air will operate like water choosing the path of lest resistance.
The testing part of this perfectly explains why it’s no big deal.
Never search for this topic or even said it out loud near a smart device. Yet 30 minutes after closing a vent in my house I get this on my top feed. God help us, we truly are in a fishbowl. 😳
I would think measuring the amperage the motor is pulling would also be a good data point to look at. Does that tenth increase, equal a substantial increase in load on the blower motor. Additionally what about different style systems. Ours doesn't have a fresh air feed and runs on cold air returns. What's the difference in starting pressure on a house that has a negative pressure system.
So should I close everything but the returns or the returns also?
I think another option is to have a booster fan installed in one of your ducts by a hvac tech.
May be related to other problems, like mold in places whre you have no heating/ventilation. Kids and old prople are more likely to have problems (asthma, allergies etc.).
So is a damper the proper way to adjust static pressure of the system?
Ac thou I close downstairs, very helpful 👍
just measure amps on the motor? would increase if static pressure increases?
Closing the vents on your furnace can definitely cause a problem if your ducts aren't installed correctly I can tell you that for a fact. Whoever installed the duct work in my house didn't do it correctly and most of the air comes out in back end my house, 2 bedrooms and a bathroom. I shut the vents in the bedrooms thinking the heat would be redirected to the other areas of the house and this caused my furnace to over heat and it tripped the flame roll out switch. Fortunately no damage was done and I learned not to close my registers.
In the winter the upstairs vents are closed, in the summer the downstairs are close. That's the only way the house temperatures are tolerable. Glad the test says it's OK because I was going to continue to do it regardless.
This doesn't surprise me... we had new vent work done (L shaped rambler, heater is in the basement roughly in the point of the L) and after that a vent in the floor of a bathroom directly above the heater was getting blasted by heat or cold, and registers on the far ends of the L were basically not blowing. Blocked off the vent into that bathroom and poof - air coming out of the far registers again. Seemed like pretty basic physics - that register directly above the heater was the path of least resistance so most of the blown air was coming straight out of that instead of pushing all that extra air through the vents to reach the registers at the far ends of the L shape of the house. By blocking the "direct easy" path, air pressure had no choice but to go through the rest of the system.
Wouldn’t you get the same effect then if you closed the door of say, a bedroom, thus impeding airflow back through the return?
that is a problem is homes with a central / common return. They are really depending on that 1 inch gap under the door to move air.
I have a couple vents closed in rooms we dont use to try and get more air to rooms that are not well served. Been like that for 30 years and same furnace motor.
I have one vent permanently closed (it was blowing towards the t-stat some 10 feet away).
Same vent was in the line going to the 2nd floor. 2nd floor now has a bit better A/C and heat.
Dirty air filter can cost you a LOT.....
So can dirty evaporator coils.
To calculate the pressure drop between the blower cavity and the heater cavity, shouldn't you subtract their respective static pressures, not add them?
actually, you want the difference between them. -0.25 to +0.25 = 0.5
One thing to watch out for even if your pressure is okay. The furnace may shutdown for high temperature within the unit.
Closing vents may not affect static pressure much, but what it CAN do is cause the system to freeze up due to low airflow or low heat load.
So why have closeable vents in the first place
It’s to direct the air, not close the vent.
@@bryanw4582forgive me, perhaps I did not phrase my comment correctly. Why not just have mesh vents that are not closeable. Would save cost and complexity.
Thank you good information
Hopefully none of your ducts have leaks or holes in them. We need an update with the ducts inspected. So maybe that's why the pressure didn't change as much. Good video
HVAC technicians say DO NOT CLOSE OFF VENTS and yet they install dampers which essentially DO THE SAME THING. All they want is the service call money to check out the system and recommend installing dampers, which DO THE SAME THING.
I don't know what a normal range is, but if the static pressure changes that little even after closing all vents, that suggests to me that there are some major leaks somewhere in the airflow because the air is still able to find pressure relief somewhere pretty easily. Is that possible?
“ insert all the way if you can, right here there is an obstruction”
Words to live by .