Great info, wish filter manufacturers would warn customers about the long term effects of using high MERV filters. Who am I kidding! They make a huge profits on the higher density filters that capture everything in sight but restrict air flow through the furnace. I switched from a MERV 13 to a MERV 8 filter years ago and saw a significant improvement in air flow, reduced noise and shorter heating and cooling cycles (increased off cycle time means more money saved). The last Rheem system I had ran for 24 years with no issues but I knew it was a matter of time before the repair bills started so I replaced it and only use MERV 8 filters. Obviously, you need something to keep all the airborne particles from collecting on the internal furnace components but it does not have to be an expensive April-wire unit or high end media filters.
as a HVAC journey person I found your video interesting. But IMO you are over stating the importance of static pressure which most home owner will not be able to measure or actually do anything about. Yes in a perfect world .5" would be great. You are terrifying them that the thousands of dollars they've spent on their furnace is being destroyed by a 1" filter. There are just too many factors to take into consideration to use a blanket statement like the title of your video. Duct design? AC? size of AC coil? Pets? Allergies? Cost?
I appreciate your input and agree. I notice he charted pressure drop on a variable system speed, but I don't have a variable system. He also referenced media filters (that were in the hundreds instead of thousands) but didn't mention the difference between those filters and why certain higher ones were fine and others weren't. Under researched video. However, good point about checking static pressure. I'll need to check if my HVAC guy does that.
Three days after my 14 year old hvac was serviced it stopped cooling down the house. Same service company tech came to check system. He concluded that it was time for an new system and offered a quote to replace it. I later discovered he had put in a pleated filter three days earlier. I replaced it with a cheap blue filter. Three summers have passed and my 17 year old system works fine. Of course i've had a new hvac service provider for the past three years.
Project Farm has performed a nice performance test with several different filters and the outcome may surprise you. I have been using 3m 1500/merv 12 filters for decades with zero issues on the hvac system. What these filters do quite nicely is cleans up the air in one's home. They are expensive and should be replaced Monthly or every two Months depending on how often your system runs. I will say my allergies and dust issue have been much better since going to these filters.
The problem with this video is most normies don't speak water column and cfm.... So it's only helping people who understand how a furnace works that probably already know that super restricted filters do more harm than good.
Sometimes not so silent. I was getting a whine, presumably from the blower motor, when using a high MERV pleated 1 inch filter. So I asked my HVAC guy about that and he confirmed I should use a MERV 4 (rock catcher), or be prepared to replace my blower motor MUCH earlier. If filtering for my health really needed at some point, I'll use some room air filter with a good rating for my bedroom.
Nothing wrong with pleated filters, as long has you combine them to get the proper surface area. As you know pressure drop is dependent on the air quantity you’re trying to push thru a given size filter. Simply put in a V filter arrangement instead of just putting one straight across the duct. I have a pleated filter media that is 4” or 5” thick. Plenty of surface area.
Ladies, this is how men think: our jobs mean this much to us. So, support your man in his job, and he WILL reciprocate at home. Make him feel bad about his job, and he'll just shutdown.
A lot of older furnaces only work ok with MERV 6 or less filters. A friend has a furnace that flashes a warning if he uses anything beyond MERV 8. But newer furnaces with ECM multi-speed motors can generally handle up to MERV 13 without making the motor struggle. My previous furnace worked fine with a 20"x25"x1" MERV 6 filter from 2007 (new) to 2020. It was replaced after a house fire in 2021 with a new, modern 92% efficiency furnace plus central air with an ECM multi-speed blower motor. I expect the motor will adjust to the filter with no loss of life expectancy. It's also quiet enough I can't tell when it's running, unlike my last furnace. The furnace came with four MERV 10, 16"x24"x1" disposable filters, the first one getting dirty quick - surely a lot of dust from rebuilding much of the house. The next filter I used barely got dirty in a month and a half (Sept. & Oct., almost no air or heat used). I replaced it with a washable, non-electrostatic, pleated, K&N brand MERV 11 filter of the same size and I'm confident the ECM motor will adjust to it. It cost about the same as four - one year's worth - of disposable filters and is easy to clean (Simple Green and a mild hose spray). The remaining MERV 10 disposable filters will be my backups when I clean the washable filter and let it dry.
Excellent explanation of downfalls of pleated filters. I'm wondering how many furnace manufacturers recommend, or supply pleated filters with their units. Appears HVAC repair people love the pleated ones, due to more frequent callbacks for repairs. Air distribution systems should be designed to provide the maximum exchange of air, be it heated or cooled. If there are no problems with allergies or excessive dust on surfaces, then why use anything like pleated that restrict air flow?
If you’re using hog hair filters or those cheap filters you can see through, you have dust in your blower wheel and evaporator. If you say you don’t you’re being disingenuous.
It’s an interesting experience, watching this video and not actually understanding much about what it means😆 I’m getting that restricting airflow is bad, makes sense 🤔
So am I extremely lucky? I have a 17 year old 3 ton Trane that uses a 20x20 filter. I use and have always used a Filtrete 2200 1" highest allergen rating for its entire life and have only ever had to replace my capacitor twice due to power surges. Why am I not experiencing any issues due to restictive air flow as you are stating?
Glad to hear you haven’t had any issues. With PSC motors they don’t ramp up and potentially overheat. The restriction of the filter reduces your airflow and may result in longer run times, but if everything has been ok for you that’s great!
Indeed. My hvac expert measured my system return air flow and ok’d the merv 13 16 x 24 x 2 inch filter I had been using from an equipment static pressure point of view. My system has too much power for my sq ft anyways. Still recently I switched to merv 8 2 inch to increase efficiency on coldest and warmest months. Still use higher merv during spring when hvac hardly runs but allergies are high, which should be fine. Though I’ve decided to mainly focus on a single high efficiency self standing air purifier for air quality needs. The hvac filters only filter when they are running and I don’t use unless too hot or cold. Also, MERV 8 is supposed to be really good and the MERV rating is done in a clean lab with minimal air pass on a clean filter. My air keeps cycling through the filter over and over and as it gets dirtier there is more restriction which I think means it filters better. This video was informative though.
In my personal experience a dirty evaporate coil was more restrictive than a basic pleated filter. So much so that I got more airflow with pleated and a clean evaporator than I did was a dirty coil plus fiberglass filter.
If people want to purify the air in their home, they need to buy an air purifier. The filters in a HVAC system exist to protect the HVAC system, not purify all the air in a home.
1" pleated filters are fine as long as they are properly sized for the amount of airflow. 16x25x1 is only good for up to about 1000 cfm and that is pushing it - beyond that, need a larger filter. They filter much better than fiberglass. The pressure drop depends on the specific filter and the air velocity through it.
Yes - Most folks should stick with a basic MERV 8 pleated filter for the common 1” filter width. If they get static pressure tested and maybe have allergy issues and can support MERV 11 then sure. But without proper testing/measurements - folks should stick to basic MERV 7/8 pleated filters.
some systems need fiberglass filter to get proper airflow - depends on filter size vs airflow and blower motor type/ductwork. without testing an individual system it is a guess. @@Kenster-man
1" 3M filtrete 1900 user here - merv 13, but also twice the media as most merv 8's on the market (1,560 sq. in) so they do not clog up fast, or create static pressure build up any faster then the typical merv 8. Oh, but they do collect smaller particulate matter MUCH better than any merv 8 on the market (including particulates from wildfire smoke) - which equates to cleaner coils, less work for your motor etc, and FAR better overall air quality in your home. My residential HVAC heating/cooling system (Maytag) is close to 20 yrs old. Other than changing out a pressure switch yrs ago, not a single issue. I change the 3M 1900 every 4-6 weeks in summer, 6-8 weeks when snow is on the ground.
Unfortunately many condos in the west coast use 1 inch. If you are not sensitive to allergies or other respiratory issues a basic dust 5 merv works great. 30 to 45 day change.
Dear Static Pressure Nerd, Your video impressed us with the seriousness of keeping the air clean and flowing as unrestricted as possible! We have a TEMPSTAR SmartComfort Heat Pump/Propane Furnace and the filter cabinet in the return duct can actually accommodate a 20x25x4 filter, but the previous owner simply had a 1-inch “horsehair” style filter in it...possibly because the AC & heat were both struggling when we bought the home. We had to have the evaporator unit as well as the heat exchanger replaced, and the HVAC tech was non-committal regarding what type of filter would be best. Without getting too crazy, would a basic 4-inch MERV-8 filter be a good option for keeping the evaporator & heat exchanger etc. reasonably clean, while also helping minimize the static pressure drop? We are thinking of this one and would love to hear your thoughts: Aerostar 20x25x4 MERV 8 Pleated Air Filter, AC Furnace Air Filter Thanks so much for sharing your knowledge!
I’m not able to find an airflow chart on that specific filter so I cannot verify 100% for sure that there wouldn’t be an excessive air flow restriction, but I would feel comfortable saying if your system is a 4 Ton or less heat pump you should probably be ok with that model.
@@staticpressurenerd5182 THANK YOU so much for your reply...and I apologize for not acknowledging you sooner. I just saw the email notification in my gmail...my bad. Very much appreciate your efforts!! (Sorry if I confused you...I used my friends laptop, so when I clicked on the email link, it logged into youtube with his account 🙂 )
What can you use to measure the pressure difference across the filter. I would like something that is permanently installed so you could judge how much resistance a new filter has and then as it got dirtier - when to change it.
Manometer is a standard, meaning as long as it has the proper fluid it will be accurate. A gauge like the magnehelic that the nerd recommended needs to be calibrated over time to remain accurate. I did this for 30 years and we used magnehelic gauges. We also ISO calibrated them with fluid manometers which is a standard.
The soilution is simple: just get a filter that is MERV 8 rated (at most!) and replace the filter(s) every 30 to 45 days. Guarantee your air conditioner will run way better.
What I never see is commentary on s system like mine. In a 2200sf house I have five filters on ceiling air returns throughout the house 2 20by20by1 and 3 14by14by 1. I usually use MERV 11 pleated filters as pollen is a concern here much of the year. Should I be concerned?
Even worse and more common, is horrible return duct and filter frame sizing. Fly by nighters completely ignore the return sizing the manufacturer recommends. Then you've got a S.P. problem no matter what filter you install. And it's expensive to fix. Flex duct, especially undersized flex duct, flows air poorly at best. But, it's the rule rather than the exception.
Awesome video man! So my takeaway's from that is that homeowners should look into retrofitting their returns (with HVAC company assistance) to accommodate a 4+ inch filter. Because the upfront cost of doing so will save money in the future from a happier coil and fan?
Your takeaways are correct. 1” pleated filters are typically $15-$25 depending the brand and benefits advertised. If you are buying 4 a year your filter costs is are at least $60. On top of this, you have the added cost of energy consumption from an underperforming HVAC system. Investing in a media cabinet and having a yearly filter cost of $30-40 (if you are purchasing them yourself) will pay for itself and then some in a few years.
generally lower merv ratings restrict airflow less. if you have the option thicker filters give the same or better filtration without raising static pressure as much so if possible try a 20x20x2 instead of a 20x20x1.
MERV 4 is probably your best bet for 1” filters. You could improve your filtration by installing a bipolar ionization unit into your return which will cause smaller particles in the air stream to clump together and get caught in your filter.
I'm having a new furnace and air conditioner put as I type this. One of the things I asked for was at least 4" media type of filter vs the 1" filter that was in there when we bought the house. I was happy to see that they put in 5" media to replace the old filter. I'll have to ask them tomorrow when they finish the job what the max MERV rating I can use. They currently have a MERV 8 filter installed. The only thing I'm scratching my head over is the brand. It's from a place called Protech. It also has stick on foam around each side. I'm not sure if this is standard for these types of filters or will I have to worry about the foam failing over time.
Never heard of the brand but for a 5” media usually I’m comfortable going to Merv 11 as long as it is sized correctly. Does the foam come attached to the filter?
@@staticpressurenerd5182 Yep, the foam is attached. 3 sides of the filter (minus the side that the door is on) and one foam strip on the door. The strange thing is I've seen photos of filters both with and without the foam on it. After speaking with the installers when they arrived this morning I asked if the foam was common. I was told that the 4" filters don't have foam but it is common to have foam with the 5" filters. I've seen reviews that did mention the foam on the filter. So, I guess my next trip to the big box store I'll have a look down the filter aisle to see what is common and what isn't. Side note: I was originally supposed to get a 5" electronic filter with this installation. But it seems that their suppliers don't have any. They wanted to switch me to a 1" electronic filter. I passed. I also found it a bit strange that they would suggest it since my original request was an update to a 4" or 5" media cartridge and they came up with the suggestion of the electronic filter along with a statement that 1" would be too small for the furnace I was buying anyway. Only to suggest that they had a 1" electronic filter available... Also, we will be approaching day 3 of the installation as they forgot to put in the UV light for the evaporator coils, the install tech disconnected my 2nd stage wire to the Nest thermostat, and they disconnected the 2nd stage wire to let the Nest control the humidifier. This makes no sense as I ran an 18/8 wire to the old furnace so there wouldn't need to be any picking and choosing as to what functions would be handled by the thermostat and furnace. So that's supposed to be cleared up possibly tomorrow.
Without a filter, my unit can take in 3400 CFM. With a MERV 5 3M Basic, that drops to 1800 CFM. Yikes. Hence I'm thinking about switching to the cheap Merv 4 fiberglass ones. All i want to do is protect the evaporator coils and blower. Merv 4 fiberglass isn't enough to protect my equipment?
Is this a commercial unit? Most residential units max on for airflow around 2400, just wondering what is out there that is capable of moving 3400 if it is residential
Depends on whats more important to you. Cleaner air or more air flow? I choose cleaner air. Nothing more important than my health. An HVAC system can be replaced when the time comes.
If you are restricting air then you aren’t going to have the clean air anyways because the velocity through the filter will be high and the dirt will sift through and get past the filter.
SPN, I really liked your presentation. I make a product that might help you sleep better at night. Would you be willing to try our new HVAC filter out. It is a 1" filter, but we use open cell foam treated with a tacky substance to stop all the dust and allergens. Currently I have MERV 6 or MERV 8. Due to the open cell nature, it can hold up to 10x more dust than a pleated filter yet still provide the air the HVAC unit needs. I'd like to send you a sample for free to try out. I'd love to have your opinion. Scott from Castle Filters
Its just another example of what people think is true isn't true at all. The reason is these filters are out of site & we never think about them. I thought air filters were originally designed to keep contaminates out of the hvac system, not clean the air.
How did all of the houses I work on as a remodeling contractor get 1” filters? From HVAC contractors. I’ve been running a Goodman 95 furnace with 1” Merv 13 filters for over 20 years. Not ideal but functional.
Without actually putting test equipment on the systems couldn’t say either way about your specific application. From my personal experience going into thousands of homes, the majority of 1” pleated filters are not sized properly and are causing airflow/comfort issues, higher energy costs and in some cases premature equipment failure. If your application is working with 1” pleated though I’m glad to hear it!
They may be behind technology but 1" filters are what is in place in most homes. So advocating for 2" or 5" or more isn't going to help anyone that isn't able financially to rip out their current system and install systems capable of handling thicker filters. The number of pleats has a lot to do with how much the airflow is restricted. I suggest watching Farm Project's testing. th-cam.com/video/RkjRKIRva58/w-d-xo.html
On my main supply duct grill vent in the living room I'm getting the same cfm output reading using a digital anemometer. I get the same cfm reading whether I use a 4 inch deep filter or just standard 1 inch pleated. Would it be safe to say the 1 inch filter is ok?
Is your blower motor a PSC motor or ECM? If it is ECM the blower will maintain the same CFM at the cost of higher electrical consumption and potential early module failure. If you are achieving this with a PSC motor then you should be ok, however it would be recommended to check static pressure on the entire system to verify you don’t have any potential issues with undersized ducts.
I just had a new Rheem furness installed and it calls for a 16x25x1 filter. Can you recommend a good filter for my new furness? I just looked at where the filter goes, and it looks like a 4 inch filter would fit in the space. Would that be a good way to go? USe a 4 inch filter instead of the 1 inch it calls for?
i way way rather replace a blower motor OVER a FULL ac system i see system die alot more from being dirty and needing cleaning that leads to rust and leaks from dirtiness then i see blowers fail i almost never see blowers fail
A new filter cabinet needs installed to accommodate for the larger media filter. Usually some slight duct work modification is necessary to accommodate for this.
Hi Static Pressure Nerd, I am hoping you can tell me if combining 4 - 1 inch filters (laying one on top of the other) would create the same effect as simply having 1 - 4 inch filter. I've been told that the more real estate a filter system has, the lower the static pressure. Thank you for your commitment to saving homeowners the terrifying expense of replacing their HVAC systems because of ignorance.
No, terrible idea. Thats 4 times the restriction. Proper 4 inch filters do not have 4 times thicker material, they have more material at same thickness bunched up within the frame.
Definitely recommend the appropriately sized media cabinet for optimal filtration and air flow. Without knowing the air flow of the electric furnace I couldn’t give you any specific model numbers
Steve T would all depend on the actual air flow and what the coil was rated for clean at that air flow. In my opinion if your drop across the coil is 20% higher than the drop the coil is rated for at that air flow it might be worth looking into cleaning up the coil.
@@staticpressurenerd5182 one issue is in the field you will have a difficult time in most cases finding the manufacturer rated static pressure drop of that particular coil. Also many coils are uncased coils within the duct work and its nearly impossible to get a model or part #. So there must be an acceptable range to refer back to. I think your video is insightful, static pressure is definitely something which is overlooked in many cases.
Steve T Definitely agree! I would say if you can’t get your hands on that information, older equipment may have a clean pressure drop of around .2-.25”wh and some newer systems are commonly .3”wc. If you are reading drops of .4”wc or higher there probably is an issue, whether it be system design, incorrect air flow settings or the coil itself being dirty. Just trying to help everyone be more conscious about paying attention to static pressure I think it will benefit both technicians and customers in the long run!
@@staticpressurenerd5182 are all True Blue low pressure drops? I see Home Depot has some FPR 5 and FPR 7. Is True Blue the brand you recommend for 1” filters?
FPR5 and FPR7 may be too restrictive depending on the size of the filter and the air flow required for your heating and cooling system. I don’t specifically recommend True Blue filters, these are only an example of a 1” fiberglass type filter. Any fiberglass type filter will help reduce pressure drops in your HVAC system. Lower pressure drops result in less energy consumption. We can modify the filtration system to have two 1” filters in a “V” formation which will allow for more surface area and as a result more air flow capacity. This would allow you to use filters with higher MERV/MPR/FPR ratings such as 1” pleated filters (Filtrete, 3M, etc.) While this method works, switching to a 4 or 5” media filter cabinet will be a more effective method of improving filtration without increasing pressure drop. Your yearly cost on filters will usually be lower on a 4” filter v. High filtration 1” filters.
You have to learn to do basic math, 20x20x1 inch filter with 8 pleats per inch = 160x2=320x20= 6,400 sq in. / 20x20x5 with 2 inch per pleat = 10x2x5=100x20= 2,000 sq in. Be careful.
WE ARE IN THE END TIMES NOW ACCEPT JESUS CHRIST INTO YOUR HEART AS YOUR PERSONAL SAVIOR BEFORE ITS TOO LATE DON'T BE LEFT BEHIND IN THE TRIBULATION OR BAD THINGS WILL HAPPEN TO YOU GET READY FOR THE END
Great info, wish filter manufacturers would warn customers about the long term effects of using high MERV filters. Who am I kidding! They make a huge profits on the higher density filters that capture everything in sight but restrict air flow through the furnace. I switched from a MERV 13 to a MERV 8 filter years ago and saw a significant improvement in air flow, reduced noise and shorter heating and cooling cycles (increased off cycle time means more money saved). The last Rheem system I had ran for 24 years with no issues but I knew it was a matter of time before the repair bills started so I replaced it and only use MERV 8 filters. Obviously, you need something to keep all the airborne particles from collecting on the internal furnace components but it does not have to be an expensive April-wire unit or high end media filters.
as a HVAC journey person I found your video interesting. But IMO you are over stating the importance of static pressure which most home owner will not be able to measure or actually do anything about. Yes in a perfect world .5" would be great. You are terrifying them that the thousands of dollars they've spent on their furnace is being destroyed by a 1" filter. There are just too many factors to take into consideration to use a blanket statement like the title of your video. Duct design? AC? size of AC coil? Pets? Allergies? Cost?
I appreciate your input and agree. I notice he charted pressure drop on a variable system speed, but I don't have a variable system. He also referenced media filters (that were in the hundreds instead of thousands) but didn't mention the difference between those filters and why certain higher ones were fine and others weren't. Under researched video. However, good point about checking static pressure. I'll need to check if my HVAC guy does that.
Three days after my 14 year old hvac was serviced it stopped cooling down the house. Same service company tech came to check system. He concluded that it was time for an new system and offered a quote to replace it. I later discovered he had put in a pleated filter three days earlier. I replaced it with a cheap blue filter. Three summers have passed and my 17 year old system works fine. Of course i've had a new hvac service provider for the past three years.
Project Farm has performed a nice performance test with several different filters and the outcome may surprise you. I have been using 3m 1500/merv 12 filters for decades with zero issues on the hvac system. What these filters do quite nicely is cleans up the air in one's home. They are expensive and should be replaced Monthly or every two Months depending on how often your system runs. I will say my allergies and dust issue have been much better since going to these filters.
The problem with this video is most normies don't speak water column and cfm.... So it's only helping people who understand how a furnace works that probably already know that super restricted filters do more harm than good.
Thanks for the feedback. I honestly wasn’t expecting anyone other than hvac techs to watch this video… but I totally understand that
Sometimes not so silent. I was getting a whine, presumably from the blower motor, when using a high MERV pleated 1 inch filter. So I asked my HVAC guy about that and he confirmed I should use a MERV 4 (rock catcher), or be prepared to replace my blower motor MUCH earlier.
If filtering for my health really needed at some point, I'll use some room air filter with a good rating for my bedroom.
Using the rock catchers does have other drawback. Equipment gets dirty, efficiency drops and stress on the equipment goes up
Nothing wrong with pleated filters, as long has you combine them to get the proper surface area. As you know pressure drop is dependent on the air quantity you’re trying to push thru a given size filter. Simply put in a V filter arrangement instead of just putting one straight across the duct. I have a pleated filter media that is 4” or 5” thick. Plenty of surface area.
Ladies, this is how men think: our jobs mean this much to us. So, support your man in his job, and he WILL reciprocate at home. Make him feel bad about his job, and he'll just shutdown.
3M Filtrete 1900 is a rare exception. MERV 13, yet low static pressure ratings when dirty.
A lot of older furnaces only work ok with MERV 6 or less filters. A friend has a furnace that flashes a warning if he uses anything beyond MERV 8.
But newer furnaces with ECM multi-speed motors can generally handle up to MERV 13 without making the motor struggle.
My previous furnace worked fine with a 20"x25"x1" MERV 6 filter from 2007 (new) to 2020. It was replaced after a house fire in 2021 with a new, modern 92% efficiency furnace plus central air with an ECM multi-speed blower motor. I expect the motor will adjust to the filter with no loss of life expectancy. It's also quiet enough I can't tell when it's running, unlike my last furnace.
The furnace came with four MERV 10, 16"x24"x1" disposable filters, the first one getting dirty quick - surely a lot of dust from rebuilding much of the house. The next filter I used barely got dirty in a month and a half (Sept. & Oct., almost no air or heat used).
I replaced it with a washable, non-electrostatic, pleated, K&N brand MERV 11 filter of the same size and I'm confident the ECM motor will adjust to it. It cost about the same as four - one year's worth - of disposable filters and is easy to clean (Simple Green and a mild hose spray). The remaining MERV 10 disposable filters will be my backups when I clean the washable filter and let it dry.
Especially the new variable speed heat pump systems.
Excellent explanation of downfalls of pleated filters. I'm wondering how many furnace manufacturers recommend, or supply pleated filters with their units. Appears HVAC repair people love the pleated ones, due to more frequent callbacks for repairs. Air distribution systems should be designed to provide the maximum exchange of air, be it heated or cooled. If there are no problems with allergies or excessive dust on surfaces, then why use anything like pleated that restrict air flow?
Because… less than pleated will not catch dust and will lead to your blower wheel/evaporator being plugged with dirt/dust
@@zachosborne6577 That's ridiculous... I've had furnaces run for decades without any problems from dust appearing on those items.
If you’re using hog hair filters or those cheap filters you can see through, you have dust in your blower wheel and evaporator. If you say you don’t you’re being disingenuous.
It’s an interesting experience, watching this video and not actually understanding much about what it means😆
I’m getting that restricting airflow is bad, makes sense 🤔
It’s a crime against humanity itself.
So am I extremely lucky? I have a 17 year old 3 ton Trane that uses a 20x20 filter. I use and have always used a Filtrete 2200 1" highest allergen rating for its entire life and have only ever had to replace my capacitor twice due to power surges. Why am I not experiencing any issues due to restictive air flow as you are stating?
Glad to hear you haven’t had any issues. With PSC motors they don’t ramp up and potentially overheat. The restriction of the filter reduces your airflow and may result in longer run times, but if everything has been ok for you that’s great!
Indeed. My hvac expert measured my system return air flow and ok’d the merv 13 16 x 24 x 2 inch filter I had been using from an equipment static pressure point of view. My system has too much power for my sq ft anyways. Still recently I switched to merv 8 2 inch to increase efficiency on coldest and warmest months. Still use higher merv during spring when hvac hardly runs but allergies are high, which should be fine. Though I’ve decided to mainly focus on a single high efficiency self standing air purifier for air quality needs. The hvac filters only filter when they are running and I don’t use unless too hot or cold. Also, MERV 8 is supposed to be really good and the MERV rating is done in a clean lab with minimal air pass on a clean filter. My air keeps cycling through the filter over and over and as it gets dirtier there is more restriction which I think means it filters better. This video was informative though.
The answer may be in your second sentence.......Trane.
Because this video is bs trying to reinvent a system that works just fine
In my personal experience a dirty evaporate coil was more restrictive than a basic pleated filter. So much so that I got more airflow with pleated and a clean evaporator than I did was a dirty coil plus fiberglass filter.
If people want to purify the air in their home, they need to buy an air purifier. The filters in a HVAC system exist to protect the HVAC system, not purify all the air in a home.
1" pleated filters are fine as long as they are properly sized for the amount of airflow.
16x25x1 is only good for up to about 1000 cfm and that is pushing it - beyond that, need a larger filter.
They filter much better than fiberglass.
The pressure drop depends on the specific filter and the air velocity through it.
Yes - Most folks should stick with a basic MERV 8 pleated filter for the common 1” filter width. If they get static pressure tested and maybe have allergy issues and can support MERV 11 then sure.
But without proper testing/measurements - folks should stick to basic MERV 7/8 pleated filters.
some systems need fiberglass filter to get proper airflow - depends on filter size vs airflow and blower motor type/ductwork.
without testing an individual system it is a guess. @@Kenster-man
Awesome video, nice presentation!
Thank you very much!
1" 3M filtrete 1900 user here - merv 13, but also twice the media as most merv 8's on the market (1,560 sq. in) so they do not clog up fast, or create static pressure build up any faster then the typical merv 8. Oh, but they do collect smaller particulate matter MUCH better than any merv 8 on the market (including particulates from wildfire smoke) - which equates to cleaner coils, less work for your motor etc, and FAR better overall air quality in your home. My residential HVAC heating/cooling system (Maytag) is close to 20 yrs old. Other than changing out a pressure switch yrs ago, not a single issue.
I change the 3M 1900 every 4-6 weeks in summer, 6-8 weeks when snow is on the ground.
Very informative, thanks!
But the filter holder slots are only 1in 😩
Unfortunately many condos in the west coast use 1 inch. If you are not sensitive to allergies or other respiratory issues a basic dust 5 merv works great. 30 to 45 day change.
A business associate I know always calls phoenix Arizona “the land of no return”
Dear Static Pressure Nerd,
Your video impressed us with the seriousness of keeping the air clean and flowing as unrestricted as possible!
We have a TEMPSTAR SmartComfort Heat Pump/Propane Furnace and the filter cabinet in the return duct can actually accommodate a 20x25x4 filter, but the previous owner simply had a 1-inch “horsehair” style filter in it...possibly because the AC & heat were both struggling when we bought the home. We had to have the evaporator unit as well as the heat exchanger replaced, and the HVAC tech was non-committal regarding what type of filter would be best. Without getting too crazy, would a basic 4-inch MERV-8 filter be a good option for keeping the evaporator & heat exchanger etc. reasonably clean, while also helping minimize the static pressure drop? We are thinking of this one and would love to hear your thoughts:
Aerostar 20x25x4 MERV 8 Pleated Air Filter, AC Furnace Air Filter
Thanks so much for sharing your knowledge!
I’m not able to find an airflow chart on that specific filter so I cannot verify 100% for sure that there wouldn’t be an excessive air flow restriction, but I would feel comfortable saying if your system is a 4 Ton or less heat pump you should probably be ok with that model.
@@staticpressurenerd5182 THANK YOU so much for your reply...and I apologize for not acknowledging you sooner. I just saw the email notification in my gmail...my bad. Very much appreciate your efforts!! (Sorry if I confused you...I used my friends laptop, so when I clicked on the email link, it logged into youtube with his account 🙂 )
Fiberglass low merv is the way to go for AC to ensure high airflow.
What can you use to measure the pressure difference across the filter. I would like something that is permanently installed so you could judge how much resistance a new filter has and then as it got dirtier - when to change it.
Magnehelic pressure gauges
www.supplyhouse.com/Dwyer-2301-Magnehelic-Differential-Pressure-Gage-0-5-0-0-5-W-C?Shopping_withoutdata&Shopping_Without_PLTV_data&gclid=CjwKCAjwtKmaBhBMEiwAyINuwIF39ew4LMQelxP-de7OgaowlfgtzyjVxstzY7r2uB1ye1JJ3WDs4xoCT_kQAvD_BwE
Manometer is a standard, meaning as long as it has the proper fluid it will be accurate. A gauge like the magnehelic that the nerd recommended needs to be calibrated over time to remain accurate. I did this for 30 years and we used magnehelic gauges. We also ISO calibrated them with fluid manometers which is a standard.
lol. You probably use K&Ns on your internal combustion motors, too?
Mishimoto all the way
I thought i was the only one laying awake at night worried about the airflow restriction.
Now there are two of us.
The soilution is simple: just get a filter that is MERV 8 rated (at most!) and replace the filter(s) every 30 to 45 days. Guarantee your air conditioner will run way better.
What I never see is commentary on s system like mine. In a 2200sf house I have five filters on ceiling air returns throughout the house 2 20by20by1 and 3 14by14by 1. I usually use MERV 11 pleated filters as pollen is a concern here much of the year. Should I be concerned?
Many homes are inherently bad and nothing can be done to reduce static pressure 😢
What is the pressure drop on the K and N washable Filter??? It's Merv 11 all I know..
Even worse and more common, is horrible return duct and filter frame sizing. Fly by nighters completely ignore the return sizing the manufacturer recommends. Then you've got a S.P. problem no matter what filter you install. And it's expensive to fix. Flex duct, especially undersized flex duct, flows air poorly at best. But, it's the rule rather than the exception.
Awesome video man! So my takeaway's from that is that homeowners should look into retrofitting their returns (with HVAC company assistance) to accommodate a 4+ inch filter. Because the upfront cost of doing so will save money in the future from a happier coil and fan?
Your takeaways are correct. 1” pleated filters are typically $15-$25 depending the brand and benefits advertised. If you are buying 4 a year your filter costs is are at least $60. On top of this, you have the added cost of energy consumption from an underperforming HVAC system. Investing in a media cabinet and having a yearly filter cost of $30-40 (if you are purchasing them yourself) will pay for itself and then some in a few years.
How does a MERV filter differ from other pleated filters?
I'm more confused, what should I use then? I have a duct return of 20x20x1.
What merv?
Are the washable ones better then because they're not pleaded?
generally lower merv ratings restrict airflow less. if you have the option thicker filters give the same or better filtration without raising static pressure as much so if possible try a 20x20x2 instead of a 20x20x1.
What do you think of aluminum washable electrostatic filters
So for most of us with 1" only option, is merv4 the best possible option or any other you would recommend on such situation?
MERV 4 is probably your best bet for 1” filters. You could improve your filtration by installing a bipolar ionization unit into your return which will cause smaller particles in the air stream to clump together and get caught in your filter.
@@staticpressurenerd5182 is merv 4 not super low ? like most particles will pass . Thanks for the great video
I'm having a new furnace and air conditioner put as I type this. One of the things I asked for was at least 4" media type of filter vs the 1" filter that was in there when we bought the house. I was happy to see that they put in 5" media to replace the old filter. I'll have to ask them tomorrow when they finish the job what the max MERV rating I can use. They currently have a MERV 8 filter installed.
The only thing I'm scratching my head over is the brand. It's from a place called Protech. It also has stick on foam around each side. I'm not sure if this is standard for these types of filters or will I have to worry about the foam failing over time.
Never heard of the brand but for a 5” media usually I’m comfortable going to Merv 11 as long as it is sized correctly. Does the foam come attached to the filter?
@@staticpressurenerd5182 Yep, the foam is attached. 3 sides of the filter (minus the side that the door is on) and one foam strip on the door.
The strange thing is I've seen photos of filters both with and without the foam on it.
After speaking with the installers when they arrived this morning I asked if the foam was common. I was told that the 4" filters don't have foam but it is common to have foam with the 5" filters.
I've seen reviews that did mention the foam on the filter. So, I guess my next trip to the big box store I'll have a look down the filter aisle to see what is common and what isn't.
Side note: I was originally supposed to get a 5" electronic filter with this installation. But it seems that their suppliers don't have any. They wanted to switch me to a 1" electronic filter. I passed.
I also found it a bit strange that they would suggest it since my original request was an update to a 4" or 5" media cartridge and they came up with the suggestion of the electronic filter along with a statement that 1" would be too small for the furnace I was buying anyway. Only to suggest that they had a 1" electronic filter available...
Also, we will be approaching day 3 of the installation as they forgot to put in the UV light for the evaporator coils, the install tech disconnected my 2nd stage wire to the Nest thermostat, and they disconnected the 2nd stage wire to let the Nest control the humidifier.
This makes no sense as I ran an 18/8 wire to the old furnace so there wouldn't need to be any picking and choosing as to what functions would be handled by the thermostat and furnace. So that's supposed to be cleared up possibly tomorrow.
Can you recommend a 1” 20x25x1 filter for those who are stuck with that size?
www.supplyhouse.com/Hart-Cooley-284200250-20-x-25-x-1-Polyester-Throw-Away-Replacement-Filter
@@staticpressurenerd5182 Thank you! Just ordered 4 of those filters.
Hi, SPN
You call it static pressure, but isn't it really dynamic pressure, since you're measuring the pressure of air in motion, not standing still?
This is way over my head. Can you please tell me what filter to use. Thanks
Bravo Sierra
Without a filter, my unit can take in 3400 CFM. With a MERV 5 3M Basic, that drops to 1800 CFM. Yikes. Hence I'm thinking about switching to the cheap Merv 4 fiberglass ones. All i want to do is protect the evaporator coils and blower. Merv 4 fiberglass isn't enough to protect my equipment?
Is this a commercial unit? Most residential units max on for airflow around 2400, just wondering what is out there that is capable of moving 3400 if it is residential
Depends on whats more important to you. Cleaner air or more air flow? I choose cleaner air. Nothing more important than my health. An HVAC system can be replaced when the time comes.
If you are restricting air then you aren’t going to have the clean air anyways because the velocity through the filter will be high and the dirt will sift through and get past the filter.
SPN, I really liked your presentation. I make a product that might help you sleep better at night. Would you be willing to try our new HVAC filter out. It is a 1" filter, but we use open cell foam treated with a tacky substance to stop all the dust and allergens. Currently I have MERV 6 or MERV 8. Due to the open cell nature, it can hold up to 10x more dust than a pleated filter yet still provide the air the HVAC unit needs. I'd like to send you a sample for free to try out. I'd love to have your opinion. Scott from Castle Filters
That would be great I would be really interested to check it out!
Whats the name of that filter and what store carries it?
Its just another example of what people think is true isn't true at all. The reason is these filters are out of site & we never think about them. I thought air filters were originally designed to keep contaminates out of the hvac system, not clean the air.
Just do a temperature rise test and if it falls within the furnace specs on the label you can take a nap.
Hmm I'm looking into a simple box fan air filter and a good air purifier for a gift
the more wind u want them go though the filter the less dirt will filter stop them, u want what result ? all depend on ur select.
How did all of the houses I work on as a remodeling contractor get 1” filters? From HVAC contractors. I’ve been running a Goodman 95 furnace with 1” Merv 13 filters for over 20 years. Not ideal but functional.
Without actually putting test equipment on the systems couldn’t say either way about your specific application. From my personal experience going into thousands of homes, the majority of 1” pleated filters are not sized properly and are causing airflow/comfort issues, higher energy costs and in some cases premature equipment failure. If your application is working with 1” pleated though I’m glad to hear it!
1 inch is outdated, bad for the customers wallet, overall a bad deal for everyone involved. 2 inch width should be the minimum, period.
They may be behind technology but 1" filters are what is in place in most homes. So advocating for 2" or 5" or more isn't going to help anyone that isn't able financially to rip out their current system and install systems capable of handling thicker filters. The number of pleats has a lot to do with how much the airflow is restricted. I suggest watching Farm Project's testing. th-cam.com/video/RkjRKIRva58/w-d-xo.html
What do you think about using multiple slotted baggie filter for a home furnace?
2 inch ++ should be a CODE REQUIREMENT
On my main supply duct grill vent in the living room I'm getting the same cfm output reading using a digital anemometer. I get the same cfm reading whether I use a 4 inch deep filter or just standard 1 inch pleated. Would it be safe to say the 1 inch filter is ok?
Is your blower motor a PSC motor or ECM? If it is ECM the blower will maintain the same CFM at the cost of higher electrical consumption and potential early module failure.
If you are achieving this with a PSC motor then you should be ok, however it would be recommended to check static pressure on the entire system to verify you don’t have any potential issues with undersized ducts.
@@staticpressurenerd5182 yes it is a PSC motor. Thank you for the info. I will be conducting a static pressure test on the system next.
I just had a new Rheem furness installed and it calls for a 16x25x1 filter. Can you recommend a good filter for my new furness? I just looked at where the filter goes, and it looks like a 4 inch filter would fit in the space. Would that be a good way to go? USe a 4 inch filter instead of the 1 inch it calls for?
Definitely use the 4 inch filter. Do you know what the model number of the furnace is?
jusr replaced my 41 year old furnace one inch filters Lol
Yolo
So what filter or merv rating would you suggest getting?
i way way rather replace a blower motor OVER a FULL ac system i see system die alot more from being dirty and needing cleaning that leads to rust and leaks from dirtiness then i see blowers fail i almost never see blowers fail
Even better to not have the blower motor fail at all!
Is he talking about the filters I put in my return ducts each month or so? I havenever replaced a filter that is inside my heat exchanger.
Yes the filter in the return duct. There is no filter inside a heat exchanger.
so what should a reaidential home have in their home? merv 5? 6?
How do we convert form 1” to 4”?
A new filter cabinet needs installed to accommodate for the larger media filter. Usually some slight duct work modification is necessary to accommodate for this.
Why no filter on the return vent ?
Hi Static Pressure Nerd, I am hoping you can tell me if combining 4 - 1 inch filters (laying one on top of the other) would create the same effect as simply having 1 - 4 inch filter. I've been told that the more real estate a filter system has, the lower the static pressure. Thank you for your commitment to saving homeowners the terrifying expense of replacing their HVAC systems because of ignorance.
No, terrible idea. Thats 4 times the restriction. Proper 4 inch filters do not have 4 times thicker material, they have more material at same thickness bunched up within the frame.
@@kayakdog121 Got it. Thanks very much.
What do you recommend for electric furnace sir?
Definitely recommend the appropriately sized media cabinet for optimal filtration and air flow. Without knowing the air flow of the electric furnace I couldn’t give you any specific model numbers
my 1in 3M 1200mpr @ 45days im getting .40 wc
what kind of static across a dirty evaporator coil?
Steve T would all depend on the actual air flow and what the coil was rated for clean at that air flow. In my opinion if your drop across the coil is 20% higher than the drop the coil is rated for at that air flow it might be worth looking into cleaning up the coil.
@@staticpressurenerd5182 one issue is in the field you will have a difficult time in most cases finding the manufacturer rated static pressure drop of that particular coil. Also many coils are uncased coils within the duct work and its nearly impossible to get a model or part #. So there must be an acceptable range to refer back to. I think your video is insightful, static pressure is definitely something which is overlooked in many cases.
Steve T Definitely agree! I would say if you can’t get your hands on that information, older equipment may have a clean pressure drop of around .2-.25”wh and some newer systems are commonly .3”wc. If you are reading drops of .4”wc or higher there probably is an issue, whether it be system design, incorrect air flow settings or the coil itself being dirty. Just trying to help everyone be more conscious about paying attention to static pressure I think it will benefit both technicians and customers in the long run!
what is the brand name of the filter with lower static preasure
The 4 inch pleated filters in my example were Aprilaire media filters. As for a 1 inch filter with a low pressure drop a common brand is True Blue.
@@staticpressurenerd5182 are all True Blue low pressure drops? I see Home Depot has some FPR 5 and FPR 7. Is True Blue the brand you recommend for 1” filters?
FPR5 and FPR7 may be too restrictive depending on the size of the filter and the air flow required for your heating and cooling system. I don’t specifically recommend True Blue filters, these are only an example of a 1” fiberglass type filter. Any fiberglass type filter will help reduce pressure drops in your HVAC system. Lower pressure drops result in less energy consumption.
We can modify the filtration system to have two 1” filters in a “V” formation which will allow for more surface area and as a result more air flow capacity. This would allow you to use filters with higher MERV/MPR/FPR ratings such as 1” pleated filters (Filtrete, 3M, etc.) While this method works, switching to a 4 or 5” media filter cabinet will be a more effective method of improving filtration without increasing pressure drop. Your yearly cost on filters will usually be lower on a 4” filter v. High filtration 1” filters.
THAT REALLY SUCKED
Probably because of the high negative static in the blower compartment
You have to learn to do basic math, 20x20x1 inch filter with 8 pleats per inch = 160x2=320x20= 6,400 sq in. / 20x20x5 with 2 inch per pleat = 10x2x5=100x20= 2,000 sq in. Be careful.
the pleats are deeper in the wider filters, do math.
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