How To Enlarge a Return - More Air Flow - HVAC Install
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- เผยแพร่เมื่อ 30 พ.ค. 2017
- How to enlarge a return air filter grille for more air flow to the system is a requirement on many installation jobs in the HVAC field. Enlarging a return is simple straight forward work described here in this video.
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I find most track homes here in CA the return is to small. Do find that also Greg? Enjoy the videos.
Yeah it was like they held a thumb up to where the return is supposed to go and said "We shall make that a 14x24 grille. That should be good enough. And put a 14" duct on it!" Lol
We upsize almost every return whenever we do an install. In Central California. Usually 20x30.
I have that same Sawzall,,,, its fantastic! I bought mine about 3 years ago or so and it still works like new.
I like the attention to detail with the caulking. Thanks for the video....
Great job Greg! thanks for sharing. as always I enjoy every one of your videos.
Thanks so much I appreciate you guys watching them!
Greg is workin' again.. Good job on return air upgrade. 16X25x1=400 sq.in/144 area 2.77
Great example of installation with plenty of detail. Thanks for this.
Exactly!! Why replace it if your no gonna change the deep of it.
Best video I have seen on these return installations…
Great video, thank you so much! I was looking for how to replace the intake with the same size, but better quality. This helped a lot. Then I saw you’re also in Sacramento. Nice surprise
Thanks!
Great video. Nice work!
Nice video Greg 😊
I like when you speed the video up. You almost get to my regular working speed..
Mrmeowcat haha yes! You're hired!
Nice job* Clean, fresh intake plus extra air flow. You get paid...customer loves the new look. DIY’s May take on a project like this including myself.
No such thing at too much return air! It's amazing how many times return air cripples a unit! I had a ten ton with a 20x20..... no wonder they were popping comps and had numerous other problems.... but oh no "We don't need more air.... It's been like that for years!"
Good work Sir!
The Republic, where did you have a 10 ton unit?
i have heard all my life as a tech , that there can never be enough returns ! lol
Good explanation and easy to understand video
You make it sooo simple. Thanks
Man your a real Pro by adding the caulking
Good work & that you can do this. A plus is you have an Attic! I'm in Fl. in condo's with Flat Roofs. Ducts coming down from roof & these built in 1979. For over 10yrs on & off sys. lets out bad air. I get sore throat/eye itchy/&/nose bothers me. Been ripped off by AC Companies and 2nd AC Unit installed in 2021. Still looking on TH-cam how to Replace this duct system for flat roofs. No one seems to know or don't want to do it. Enjoyed your video and wished I had system I could do DIY.
If you make a return grille larger but keep a 4 inch deep can, you're missing the bigger picture. A 3/4 gap isn't big enough for the air to move behind the filter. That's why you see the center of the filter get dirty first. It only starts using the area outside the duct tap after the center is plugged. This leads to a non-linear filter loading curve that's less perdictable. Why not make the can 12 inch deep and use the entire surface of the filter? I'm guessing it's because the distributordoesn'tt stock anything but 4 inch cans. With a good thermal imager, you can see where the grille is pulling and where it doesn't. It shows up better in Grayslake than color.
I've only ever heard someone say "perdictable." I've never read it in print!
super nice job!!!!!!
great video
Love the sound track.
Also when you order the actual return plenum do you order 16×25 exact or do you take something else into consideration and give it 1/4" extra or less?
So did the size of the flex increase if so from what size to what size
I have a house that is at 1100 square feet and I have a 3 ton unit. Occasionally it will leak heavy from the vent when the unit shuts off. I had someone come out to check it and they said my unit doesn’t have enough space to breath? Would this help with the problem?
Nice Greg
I got a new return grille 20x20 and it's alittle smaller than my current old one and the filter is snug also I've searched for wider dimensions but none that goes to 23 on the outside
its only make the air flow to ceiling, for warm air or cool air out ??
another good video man! what type of symptoms do you get from having to small of a return?
Sal C high static pressure which causes poor performance,noise,freezing of the system,low or no superheat on fixed units which eventually leads to premature compressor failure.
Small grill is replaced with bigger grill. What about the return duct did you guys install bigger return duct?
Where did you find that saw that cuts rhythmically and plays music? lol
WOW!!! E-X-C-E-L-L-E-N-T Greg, this is just the thing that I need now... I have TOO many questions, maybe you will have pity on me and answer some of them. First, How much should that job/repair cost me? Second, How much time should it take to complete? and Third, Where do you live, and can I hire you to HELP me??? THANKS for a Great video.
We charge about $1200 to do it. But so many of our installs have to have their returns enlarged, I just add it to my install pricing. It takes about 1 to 4 hours depending on the tech. Haha! Yes you can hire me! We are in the Sacramento, CA area and would love to help you out. Are you here in the area?
Yes, VERY close Portland Oregon... LOL..
Greta video, Thank you for sharing your knowledge. I have a Question for you if that's ok. A contractor in our Area is putting a 3.0 unit in our first level but we originally had a 2.5 unit. I told the contractor that we didn't need a 3.0 Ton unit because the all ducts were build for a 2.5 tons. He told me that we should no have any problems. Can you put a 3 Ton unit without affecting the duct work? Would the machine be able to breath? If he alters the intake duct then he has to increase/decrease the outtake ducts right?
It is only 200 cfms difference. So I would say it not going to make a big difference. If anything you'll get better velocity if the air. Technically it can affect the static pressure of the system so keep an eye on that.
@@foxfamilyheatingandaircond4696 thank you sir
does bigger or smaller reduced noise, my furnace it’s 1 year old and the filter it’s located in living room and it’s loud any idea what i can do ?
But a 12 inch duct can only carry so many cfm so how does that make more return air. Just wondering and no im not a hvac tech
Sorry, but I have to ask. Does or is the diameter larger too?
Rather than going to all that trouble of increasing the size of the original return air boot and grille, I would have simply added a 2nd return air duct, boot “can” and grille.
Good job and video👍
Music👎 Lol.
Was the noise reduced ?
Recommend eye pro next time
Hahaha thats so EXTREMLY intense!!
I hope the collar is not the same size.
That was my question lol
Love the "Minni-Me" sawzall....but where's the safety glasses, brah? Nice re-do!
Oh...I see them now...maybe I should invest in some real glasses?
Good tip putting the screws in at an angle. Hows that calking taste? lol
Brad B gotta get that finger wet!
great video, with an 3 tons of central ac, the return air 30x12, is it big enough ? thanks
You need a 20 x 30 for 600 CFM for 3 ton unit
@@internetabyss thanks for your info, mine is 30x12, which is too small, what will happen if the vent opening is too small ? mine is running for 6 years , it seems running ok
Sure wish I could do this. My 14x20 return has a box jammed right up against the pitched roofline. Not sure I want to completely redo the location and rebuild the framing, but that's what they should have done initially.
Why not add another return ?
Existing return is located at top of start landing (in ceiling). An additional return would have to occur closer to opposite end of upstairs hallway, assuming that's OK. In the meantime I hope to replace my 1" filter with a 3" if I can get it to fit on the filter frame opening.
That is 1 bad ass little saw zaw u got, what kind is that?
rigid. they're like 100 bucks. I love it. I won't use battery powered sawzalls they always fail right when you need them the most. lol
@@foxfamilyheatingandaircond4696 I've got to get me one lol do you happen to have the model number?
Can someone please explain why all these homes have returns on the ceiling? I mean, why are you sending your "good air" (cool in summer, warm in winter) through the return?? From what I understood, returns should always be at the floor level so that the "bad air" (warm in summer, cold in winter) can go through the central air system to be adjusted to proper temps.
You do know that hot air rises and cold air sinks?.....
In the south, we want our returns on the ceiling tontake the warm air back into the unit.
I have a 2 story tract home built in 97. It has a 5 ton unit in a 1660 sqft home. I live in a dry part of southern California so it cools off the house FAST(it’s a beast) and I don’t have humidity issues. I’m wondering if my return is well sized, especially since I use thick pleated filtrete filters 1900+. It’s a 20x30x1 in the ceiling. Do you think I should have it enlarged or is that a good size for my application?
That is a huge fuckin unit for a house of that size lol I would not use the thick pleated filters because that heavily restricts air flow. You should be fine with the size of return. Use the EZ flow air filters, they're not as bad as some people will tell you but the ones you're using are very bad for the unit
Km
Sell as an obvious needed retrofit with a "free" upgrade, + ? "Any concerns with air quality?". Deeper box/c-can/pan or with air flow transition. Install a M11 or greater filter(+h.o. answer to ?, M11+) Since most homeowners change a filter, if they even know there is one, once a year you're doing them a favor. Not only air quality wise but energy $ wise. The filter & box will pay for themselves easily. +Add them to your Maint. Program obviously. I don't recommend shallow pans, especially in CA. where the definite legislative movement is towards energy savings and air quality. Next thing you know some HO is stuffing a M11(+) in the can and only using 40% of the surface area of a deep filter and ends up with the dreaded "circle of junk" on the filter face. But, there's the "well there's air sideflow through a deep filter" crowd. Sure, and there's premature compaction and pleat folding of them from sideflow.
Real good input here! Thx.
I'm confused, the return air duct in the ceiling will cause the cool air to go out and won't cool the house, am I right?
Thats stupid. The return air goes back into the air habdler or furnace gets cooled or heated and sent back into living space
@@leonelramirez3231 How if it's not connected the furnace. I don't understand this. The air just goes into the attic and exit through the roof. How does it get recirculated?
I don't understand this either.
It is connected he just didnt show it. It has a 14-18 inch flexible return duct.
@@leonelramirez3231 So my next question would be what would be a solution to this problem if you had an upflow furnace and there is no return in the ceiling. No return on the top floor at all because the furnace is in the basement.
OMG. You went though all that shit to enlarge a 14 by 24 to a 16 by 25? Why not make it worth your while and enlarge it to 25 by 20? And dude, you didn't explain it only gives a bit more filter area. No more air flows to that unit by doing that unless you enlarge the entire return. You need to clarify that. And since it's in an attic and your doing it for EFFICIENCY of the customer, why not insulate that return box since it's in a stifling hot attic. No, kicking insulation on the box doesn't cut it.
It looks like duct size increased from 14" to 16", so at least a couple hundred cfm improvement.
Code resatricions may hinder your placement of returns/supply w/i radius of smoke-detectors.
Very true. Some code inspectors have called my previous employer in certain cases where the smokes were placed within 1 or 2 feet of the register.
That ceiling light is in a bad position not being in the middle but the duct needs the room in the middle.
I can tell you have been doing this awhile. I.e. Experience
Thanks for the compliment 😁
Interesting but he's not wearing any eye protection for the first few minutes, when using the saws all power tool. Hope he doesnt get hurt.
CFM Airflow should be checked...
I have a 60-K 95% propane furnace or 57000-Btu/hr Output, no central A/C; Temp-rise 59°F * 1.08 is 63.72; 57000 / 63.72 is 894-CFM. Approximate CFM…
Simple & easy to post a permanent reference CFM for a system...
There is virtually no-one checking airflow CFM before charging an air conditioner or heat pump system. This is very essential in order to accurately charge the system, therefore, I will provide the easiest way to get a record of the CFM on the system; you are checking to see if it falls within the 350 to 400 CFM, or in hot dry climates up to 450 CFM per ton category. You need to get it there…!
During the Spring, Fall, and Winter months and even early morning in the Summer months you can use the furnace BTU Output and temperature-rise above the return air temperature; multiply it by 1.08 & then divide that number into the Btu/hr Output to get a pretty good CFM airflow number. It is close enough to get it within the correct CFM Zone…
If your air flow is not correct you will be getting false superheat and sub-cooling readings.
C’mon guys, it’s time to start doing things close to the RIGHT Procedural WAY…!
Should all HVAC guys know how to do this & can a return be too big???
Yes they should. A return can't be too big.
having return flow is over rated :)
could you have added a second return, vs. changing that one?
Then you sir obviously do not know what you are doing. And I would hope that you are not in the industry for the sake of all your potential victims!
No one provides Techs with the formulas for right sizing filter rack areas to achieve proper velocities through them; I will:
HVAC Airflow- Duct, filter’s Ak and other Component Sizing Formulas:
Ak area of the filter: CFM / required or desired fpm velocity
Example: 3-Ton @1200-CFM / 280-fpm= 4.2857142-Ak
Heating only 858-CFM / 220-fpm = 3.9 (Ak) SF open-air-area.
My filter numbers:
I have (3) 12” x 32” filters 384-sq.ins., each x 3-filters is 1152-sq.ins / 144 is 8-sq.ft. | so, 3.9-Ak sq.ft., / 8-sq.ft filter area is 0.4875% or, filter’s Ak %.
**A tested 59°F heating mode temp-rise x 1.1 is 64.9 furnace 55,500-output / 64.9 is 855-CFM 3.9 X 220 = 858-CFM; Had a tested 855-CFM; very close. …
Therefore, a single 16X25 filter is 400-sq.ins. / 144 is 2.7777 400*.4875=195-sq.ins./ 144=1.3541666-open-air Ak of the filter).
Filter’s Ak = CFM / fpm velocity through the filter in fpm
FPM= CFM / SF Ak AREA of filter
CFM = fpm X SF (Ak) AREA of the filter
Required Ak % of the filter’s area= smaller actual Ak area ‘/’ filters actual larger listed Square Foot size area.
**Print & Save all these Formulas & USE them to properly size filter rack areas to achieve proper low filter fpm velocities...!
Also; a 6” duct; so 6" x* 6” = 36 *x .7854 = the 28.2744-sq.ins" / 144 = 0.19635-Ak-sq.ft area.
** I like the Purolator P-312 white Industrial Strength Disposable Synthetic Panel MERV 4 filters - decent pressure drop with good filtering - you have to order them on the Internet; has a .16" PD @300-fpm; .10" PD @200-fpm velocity
.
**7 out 10 HVAC systems by exhaustive testing have airflows out of tolerances, this can cause high cost ECM motors to exceed their rpm Rated limits & thus overheat & fail…Also results in very high cost compressor failures!
**There is also a direct correlation between the blowers 0.5” or 0.6”WC and the total equivalent length (TEL) of the duct system regarding the amount of remaining available steady pressure. Jack Rise having done many hundreds of Manual D’s friction rate sizing has stated that you may need to have 0.4 inches if you have a total equivalent length of the ductwork in order to get a friction rate design of 0.08 inches of water column for adequate velocity in the supply runs.
** Okay Manual D; .4” * 100 = 40 / ‘a very high’ 500-TEL is 0.08” WC friction rate to achieve enough velocity. Manual D on the Internet shows an improper example of designing friction rate for the supply side air-flow; you need a much higher rated static pressure oversized blower than .6”. to have .25” to.3” of Available Static Pressure (ASP) remaining.
They show a 0.6 inch water column blower and all pressure drops result in an Available Static Pressure (ASP) of only 0.17” WC; .17” * 100 is 17 / 500-TEL is 0.034-FR; and therefore, supply air ducts would be sized way to big and would result in an extreme low velocity of airflow through the ducts.
**A more reasonable situation is .25” (ASP) Available Static Pressure & 300-TEL, or less; 25/300-TEL is .083” (FR) Friction Rate to achieve proper airflow velocities.
This is amazing. Thanks for sharing!
Next time try giving the grill a smack, a good jar will often shear that excess paint.
Foil tape won't stick to drywall ceilings. Should of used GE 100% silicone for a permanent seal. Unless you enlarged the return duct, what is the purpose? Larger grill opening I guess to let more air in? Should of rigged it for some 4 or 5 inch thick filters. Those 1 inch hoopties are lame. Wait you didn't install a filter there. So now you have dirty return ducting. OK, I don't get it.......
That is hardcast/ rolled mastic not foil tape. Also the duct was already disconnected so they might be doing a new install and adding a filter cab furnace side though that was a RaFG so maybye not
.
Why would you install the filter before you install the ducting to the vent? This comment is as dumb as the guys who think he is just venting into the attic. I have never seen so many idiotic comments in a video.
Wear a mask dude...
gross place.
He says "you new guys put that tape on bla bla bla. No, that's why you leave 1/2 inch sticking DOWN, so you can bend a flange over against the sheetrock. I'm a sheetmetal guy. I can make sheetmetal fittings, not just boxes. This is a guy who thinks his work is the best, but he hasn't seen good professional work by a company with a sheetmetal shop. Guys got lazy, they don't wanna make and install all that duct anymore. It wasn't a "skill" to people, it was just mere labor, so companies started phasing it out because guys are better than being "just a laborer", they're a "Mr. Tech" who says"I ain't making duct or installing it". The company I worked for was notorious for fucks like that. They thought they were above ductwork. That's fine. That's why companies do shitwork with plenums and ductboard. Companies like the one I worked for have a replacement to do every single day. They had enough work to keep 2 duct crews going on installing ductwork and setting units and making ductwork. Why? People LOVE that custom sheetmetal work and it lowers their power bill. Then they tell their friends how good of a job it is and by the end of it, everyone wants that company doing their install. Companies that do work like this get a few installs a month. The rest service calls. Do the math. Install labor for the day or gas and time burned riding to the supply shop for parts. Ah huh. The ones with a sheetmetal worker get the installs. If it was YOUR house, would you wanna see a square box attached to the furnace with something rigged to it? OR, would you want to see nice curved metal fittings that look nice and merge right into the rest of the duct. Ah huh.