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Is my Ac air handler filter the right size

Hey all, I replaced my old 3.5T ac 25 yr old unit with new. Approx. 2200 sg. ft. home/ 2 levels with open area in the middle. Everything was working fine, just needed electric back up heat to my wood stove and looking for efficiency. The old was replaced with same size, no changes to duct, no work in the attic...just a new compressor and air handler. No tests or measurements, the company just went off the old size since it was working. Issues....I have 2 return vents that will not hold a Kleenex up to register when running, a few of the others will that are closer to the unit. Also, when the temp outside is 85 it will not keep up with 72 on the thermostat. Runs all day non stop. Again...nothing else was changed, and it was working before. They did tell me they had to put a smaller (hgt wise) unit in do to space. This unit only has a 20x16 filter. The old was at least 22x22 if not a 24x24. Is the smaller filter area not sucking enough? Starving? They did do a temp check and had 49 at the unit and 53 at a register 30 ft away. If i run with the filter out will I be able to tell anything? Do I need a 4 ton unit? Thanks for any help you all can give.

Comments

  • Jamie HallJamie Hall Member Posts: 13,403
    At the risk of a stupid question -- what is the capacity of the new unit, in tons?
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • mikeapolis mikeapolis Member Posts: 16
    Have you tried running the system (carefully) without the blower door? It's really a shame they didn't take the time to run a Manual J. Are you using a cheap filter or something like a 3M Filtrete?
  • jonboyjonboy Member Posts: 10
    Jamie it was a 3.5 ton system, and they replaced with the same size. Trane.
    mikeapolis, I will try running with the door off tonight and see what that looks like. I believe they did have a pleated 3m filter in it. I only looked once.
    I do have an outdoor wood burner, and they had to put in a heat bank for that. It's been running right now with it out. They thought it might be pulling down the degrees, but that wasn't a problem either. My concern is as soon as I put that back in, which will probably be next week, won't that restrict airflow even more? You all are the experts, but my thought is...the old and new use half horse motors. The old was sucking through a garden hose (per say) with the 24x24...using the same motor, the new is sucking through a straw 20x16. If it was balanced before with a 24x24...how can it be balanced now with a smaller opening? Thanks for responding. The company is working with me, even up to the point of replacement. this has been going on since July. I asked for a pressure test, to see if I was pulling as much as pushing, and I saw them both look at each other, like they didn't want to or didn't have the equipment. By the way , I haven't given them any money yet.
  • mikeapolis mikeapolis Member Posts: 16
    Those 3M filters really cause a lot of airflow restriction. Having the blower door off then back on during a static pressure test will definitely show what's going on.
  • ChrisJChrisJ Member Posts: 11,249
    If it's a Trane it might be a positive pressure air handler, so not sure what the blower door being off will do on such a unit.

    I'd ask the installer to install an AirBear Supreme 2000 or similar and pay for the upgrade. It's a 20"x25"x5" filter. Use the Merv 8 filter not the 11 or 13.

    How is the rest of the ductwork sized?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    mikeapolis Zman
  • ZmanZman Member Posts: 6,002
    Deeper filters have more surface area and therefore much less resistance than shallower.
    I keep hearing folks talk up Merv 13 filters to help with Corona. The reality is, unless your fan is sized large enough you will significantly reduce your air flow rates which may be more important. If running a Merv 13, you need to change filters much more often.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ChrisJChrisJ Member Posts: 11,249
    edited October 15
    Zman said:

    Deeper filters have more surface area and therefore much less resistance than shallower.
    I keep hearing folks talk up Merv 13 filters to help with Corona. The reality is, unless your fan is sized large enough you will significantly reduce your air flow rates which may be more important. If running a Merv 13, you need to change filters much more often.

    I'm using a 20x25x5 Merv 8 Airbear on my 3 ton system that I intentionally oversized the ductwork on and it's tough to keep the total static at 0.5". Sometimes I get 5 months from a filter, sometimes only 4.

    I can't see a MERV 13 working in any residential system honestly unless it's really grossly oversized, like a 20x25x5 on a 2 ton system.

    Honestly, it seems like pleated 1" filters have no business existing in residential period.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • jonboyjonboy Member Posts: 10
    ChrisJ, I will speak to them about it. It is a Trane Tam4A0A36S31EDB model. As far as the duct, it is original to the house. 25 yr old. The only thing i can tell you is there is a bulkhead around the supply line where it pulls air back for the return. If that makes any since? So there's not a dedicated return duct pipe per say. I'm just frustrated because everything worked fine for the last 25 yrs, and now they switched out 2 items (compressor and airhandler) and not working correctly. Uhg! Should have left well enough alone.
  • jonboyjonboy Member Posts: 10
    zman, thanks for the info. I'm not so much worried about covid as I am tested weekly. I see it daily and would rather have covid(which I have had) and my AC running correctly. Probably because I know about covid and not much about AC.lol
  • Matt_67Matt_67 Member Posts: 186
    A Trane TAM4A0A36 is a 3-ton unit. The 3-1/2 comes with a 20 x 20 x 1 filter slot.
  • jonboyjonboy Member Posts: 10
    Matt_67 I will have to look into that. Thanks for the info. How do you know by the numbers how many ton?
  • Jamie HallJamie Hall Member Posts: 13,403
    On Covid -- folks, it's a virus, not a bacterium. You are NOT going to filter it out without going to a full bore HEPA system, and even then it's doubtful.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
    mikeapolis
  • ChrisJChrisJ Member Posts: 11,249
    Matt_67 said:

    A Trane TAM4A0A36 is a 3-ton unit. The 3-1/2 comes with a 20 x 20 x 1 filter slot.

    And, the plot thickens.
    What model is the outdoor unit @jonboy ?

    Typically a *36 is a 3 ton.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • jonboyjonboy Member Posts: 10
    ChrisJ, this is bothering me now! Stay tuned as I will have to wait a few hrs to get home. I do appreciate you all helping me out!
  • jonboyjonboy Member Posts: 10
    OK...rest of the story. I checked both unit and they are 3 ton. That's not enough for a 2200sg ft home with cathedral ceilings and sky lights correct? I know it had a 3.5 ton unit before . Let me ask you this...would a 3.5 ton unit have less than a 20x20 filter. The old unit had a odd size filter, like 22 1/4x 22 1/4. Help me get there!!!!
  • ChrisJChrisJ Member Posts: 11,249
    edited October 16
    jonboy said:

    OK...rest of the story. I checked both unit and they are 3 ton. That's not enough for a 2200sg ft home with cathedral ceilings and sky lights correct? I know it had a 3.5 ton unit before . Let me ask you this...would a 3.5 ton unit have less than a 20x20 filter. The old unit had a odd size filter, like 22 1/4x 22 1/4. Help me get there!!!!

    My system is a 3 ton 2 stage (runs around 2 tons in low) and I have the filter I recommended in the above comment, a 20x25x5" Merv 8. I highly urge you to get one put in.

    As far as 3 ton vs the size of the building that all depends on the building's construction, where you live and what you like.

    I have 3 ton in a 1600sqft house and I max it out every summer, but I like it 72 during the day and 68 at night and my house leaks like a sieve and has very little insulation. If the 3 ton keeps you comfortable, then it's ultimately better because it's cheaper to run, cheaper to replace and should keep humidity slightly lower on cooler days

    If the system doesn't keep up and things end up too warm for you, no, it's not enough.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • jonboyjonboy Member Posts: 10
    ChrisJ, I'm going to call the company today. I'm sure he is going to say "he thought the old one was a 3 ton". Does any 3.5 ton unit use a 20x16 filter or would it need to be bigger? Reason is, I have no paperwork to prove it was a 3.5 ton. I only know the size of filter, and it worked fine with a bigger filter. They have already disposed of old unit. Just my knowing it was, is all I have right now. Other than it's not working correctly with what they have.
  • motoguy128motoguy128 Member Posts: 178
    What’s your location? Sorry if I missed it. 85F, sunny, humid may be close to design conditions if you in a northern climate. So running all day to maintain 72F may be spot on. Longer a system runs, the more efficient it is.

  • EdTheHeaterManEdTheHeaterMan Member Posts: 798
    edited October 18
    A two-stage unit will run all the time. That is what it is supposed to do. With the single-stage unit when the thermostat is satisfied the compressor goes off. With a 2 stage unit when the thermostat is satisfied (for the second stage) the compressor drops to the first stage (not Off). If the low stage is enough to meet the load, Then it will go off... but mostly it will not and just continue to run on Low until the indoor temp increases to the point where the Second stage comes back on. During the warmer months, if your 2 stage system actually goes off. It is Too Big.

    That said, Were you comfortable all summer? Yes... correct size, if not, then 3 Ton may not be large enough and you will need to go to 4 Ton. (Unfortunately, They don't make half-ton sizes in 2-stage.)

    Edit: the smaller air filter may also contribute. First I would use a larger surface air filter indicated above by others. (pay for the upgrade but size for 4 ton AirBear suggested above) Have the installer put in writing (by email or letter) that they agree to install a 4 ton 2 stage next year if the larger filter does not solve the problem. (that is why you should get the larger capacity air filter now) I would also let them know that you are willing to pay for the larger size. (As if the system was installed that way in the first place. The difference only not for the extra labor)

    3 ton TAM4A0A36 is 17+" wide
    4 ton TAM4A0A48 is 23+" wide

    That may be an issue. the location opening may need to be increased.


  • jonboyjonboy Member Posts: 10
    Great, thanks all. I will get with the company and see what they say about the bigger filter with the same unit. To be continued!
  • GWGW Member Posts: 3,789
    Too small, 2.22 sq ft of filter for 1200 cfm- 545 feet per minute. 300FPM is good, but sometimes the math is hard to achieve without redoing the whole thing (more money)

    try to be mindful how you communicate all this. Some homeowners can pull this off well, other homeowners are prickly and that’s when the fun starts 


    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    www.wilsonph.com
    [email protected]
  • GWGW Member Posts: 3,789
    After more contemplation, Trion Air Bear rates their filters in the 500s, but these are larger pleated filters. A little 1” filter- not super good 
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    www.wilsonph.com
    [email protected]
  • jonboyjonboy Member Posts: 10
    Thanks GW. I'm good with the company. In fact they do alot of work for me at my job, and I have the say so on who does the work. Not going to use that, but it just seems like they are dragging their feet and I don't have any patient.lol He did say he might have to call in his air guy.lolllll I think if it was me, i would have already done that. I'm sure they are crazy busy, but you have to take care of customer,(finish the job). I will keep you all up to date on what I find out.
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