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  1. #1
    Join Date
    Aug 2011
    Posts
    17

    post aeroseal on supply only, still large return leaks- how to inspect/fix?

    I have a 2 story house, 4 ton downstairs, 2.5 ton upstairs- 3900sqft- in texas. This is 1960s constructions so bad insulation, leaky, etc is a given. I've added more insulation, sealed can lights, sealed all around, better, but still not great.

    The downstairs duct work was in bad shape originally- had 2 supply ducts COMPLETELY disconnected spewing a/c into the attic. Had a local A/c company come out and inspect everything (blower testing) and they did aeroseal on the downstairs supply ductwork (original mostly sheetmetal ductwork-most of the downstairs ductwork is inaccessible due to 2 story setup). 3 of 4 returns are in wall returns (between the studs, unlined). Per their post-aeroseal testing, the supply side went from around 300 to 70 (?cfm) leakage, so I'm happy with that. However the total system (supply and return) still shows around 20% leakage (sorry for the incorrect terminology, don't have the report in front of me)- and the report said I'm still losing ~1ton of cooling (of a 4 ton system). I asked them about sealing the returns and they didn't seem to say much other than not wanting to do it. Since then I've contacted aeroseal who said the returns could be sealed. Maybe I'm wasting money on this, but I'm trying to make this house comfortable and this still bothers me:
    1)My concern is there are large holes in the returns sucking in 150 degree attic air- anyway to inspect the returns? Run a camera up them from the in wall returns?
    2)Shouldn't they be able to aeroseal these also? My understanding is they could, it just takes a while. Especially if we make sure there are no massive holes, aeroseal should seal these well? If not, I'm not opposed to some sheet rock work if it means I get back 1 ton of cooling...
    3)I paid good money for the aeroseal on the supply side, but feel like only 1/2 the problem was addressed- why is this so difficult to fix?

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,046
    Quote Originally Posted by wp746911 View Post
    I have a 2 story house, 4 ton downstairs, 2.5 ton upstairs- 3900sqft- in texas. This is 1960s constructions so bad insulation, leaky, etc is a given. I've added more insulation, sealed can lights, sealed all around, better, but still not great.

    The downstairs duct work was in bad shape originally- had 2 supply ducts COMPLETELY disconnected spewing a/c into the attic. Had a local A/c company come out and inspect everything (blower testing) and they did aeroseal on the downstairs supply ductwork (original mostly sheetmetal ductwork-most of the downstairs ductwork is inaccessible due to 2 story setup). 3 of 4 returns are in wall returns (between the studs, unlined). Per their post-aeroseal testing, the supply side went from around 300 to 70 (?cfm) leakage, so I'm happy with that. However the total system (supply and return) still shows around 20% leakage (sorry for the incorrect terminology, don't have the report in front of me)- and the report said I'm still losing ~1ton of cooling (of a 4 ton system). I asked them about sealing the returns and they didn't seem to say much other than not wanting to do it. Since then I've contacted aeroseal who said the returns could be sealed. Maybe I'm wasting money on this, but I'm trying to make this house comfortable and this still bothers me:
    1)My concern is there are large holes in the returns sucking in 150 degree attic air- anyway to inspect the returns? Run a camera up them from the in wall returns?
    2)Shouldn't they be able to aeroseal these also? My understanding is they could, it just takes a while. Especially if we make sure there are no massive holes, aeroseal should seal these well? If not, I'm not opposed to some sheet rock work if it means I get back 1 ton of cooling...
    3)I paid good money for the aeroseal on the supply side, but feel like only 1/2 the problem was addressed- why is this so difficult to fix?
    The Aeroseal will not work on the wall spaces. Using the cavities of the walls is a mistake made by a lot of builders and contractors to save there money at the expense you spending yours for years to come.

    It is not that hard to fix, it may take building some soffits but it can be done

  3. #3
    Join Date
    Aug 2011
    Posts
    17
    Thanks- so your suggestion is to just move the returns from the floor up to the ceiling area? Could they just put a return in the ceiling itself (seems pretty common in the south)?

    If the in wall returns were addressed/removed, then I assume they could aeroseal the rest of the return system?

    Does this sound like a reasonable concern? I don't mean to overly concerned, but losing 20%+ of my HVAC (which is a major expense in texas) drives me nuts. I'm still considering replacing the a/c/heat unit in the near future but don't want to spend money on a nice unit to have crappy ducts...

  4. #4
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,046
    Quote Originally Posted by wp746911 View Post
    Thanks- so your suggestion is to just move the returns from the floor up to the ceiling area? Could they just put a return in the ceiling itself (seems pretty common in the south)?

    If the in wall returns were addressed/removed, then I assume they could aeroseal the rest of the return system?

    Does this sound like a reasonable concern? I don't mean to overly concerned, but losing 20%+ of my HVAC (which is a major expense in texas) drives me nuts. I'm still considering replacing the a/c/heat unit in the near future but don't want to spend money on a nice unit to have crappy ducts...
    20% is a lot especially when it is the return in unconditioned space. It can overcome the system by sucking in 100 degree + air.

    It is hard to tell you exactly what to do without seeing the entire layout.

    Consider point A to point B and how can I get there. Through closets, build soffits, false beams etc.

  5. #5
    Join Date
    Aug 2011
    Posts
    17
    thanks- those were my concerns. I'm gonna see if I can't find another HVAC company to come out and address my concerns (I'll use the contractors map here).

  6. #6
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    2,998
    yeah aeroseal takes your money and leaves you with leakage
    they can't address. that is why they went out of business here.
    they can't seal gaps over 1/4"..and those are the huge sucking
    holes. give me a bucket of mastic and a roll of mastic tape
    anyday!

    describe your returns.
    do you have a return chase with the filter on the wall low
    to the floor or high up in the ceiling?
    returns can be sealed, I do it all the time.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  7. #7
    Join Date
    Aug 2011
    Posts
    17
    First floor:
    I have 3 return vents which are at floor level- these 3 have no filters and open into wall cavities encased my drywall/studs- no lining. The air travels up, and connects with ductwork up top. 1 return is located close to our stairs- up high.

    This whole thing has been very frustrating. I have spent some significant $$ so far for some improvement, but I'm pretty sure I'm still leaking badly. The house needs all the help it can get. The second story covers at least 1/2 of the duct work (the main runs are generally accessible, with the branches running between floors. Accessing some of the duct work would require sheet rock work (which at this point I'm not opposed to). In an ideal world, I would LOVE to just gut all the duct work and get a nice air tight system with an efficient AC unit- not just for efficiency reasons but for comfort reasons... but with the second story there blocking access a total gut is likely a really big proposition.

  8. #8
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

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    Last edited by jpsmith1cm; 08-15-2012 at 06:31 AM. Reason: non AOP member

  9. #9
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,998
    rater guy

    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

    Additional infractions may result in loss of posting privileges.

  10. #10
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    5,674
    You just need to find a contractor who is willing to get in there and fix the problem, make sure they test in and out to show the improvements (blower door, duct blaster). Also there is always the option of ductless mini splits with multiple zones. Zero duct loss because there is no duct

  11. #11
    Join Date
    Aug 2011
    Posts
    17
    so how do I go about finding a good contractor? Seeing you guys talk on this forum I'm impressed by your knowledge and professionalism, but the HVAC guys I've had out (4 different companies, many in business for a long time, ranging from cheap to expensive) just really haven't impressed me I gotta say. I do see there is a map of contractors who are on this forum- go off that? I'm in Fort Worth- any recs (if you can do that?)?

    I'm tempted to pursue the guys who did the original aeroseal to have them finish the fix they started $$$$.

  12. #12
    Join Date
    Sep 2009
    Location
    Arnold mo
    Posts
    3,795
    Another concern you need to consider is whether or not your existing duct system was designed & sized to handle your 4 tons of cooling. Air sealing the duct system seems like a good idea, but if your duct system is too small for 4 tons of cooling, your system may have been functioning relatively well BECAUSE of the air leakage. Air sealing will increase the static pressure and make it more important that the duct system is sized correctly. The good news is that when it comes to time to replace the equipment you may be able to put in a smaller system, one that your duct system can handle; especially if you included other improvements to your home to reduce its air leakage etc....
    An answer without a question is meaningless.
    Information without understanding is useless.
    You can lead a horse to water............
    http://www.mohomeenergyaudits.com

  13. #13
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    5,674
    If you still have 20% duct loss after aerosol it probably means there are larger leaks than aerosol can fix. I'm not a big fan of aerosol. I like to get my hands on every joint, if possible, so I know it's sealed. Yes the contractor map is good. Look at posts of the contractors in your area and see if you are impressed. Good luck

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