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  1. #1

    What should I do??

    I am new to the forum and whenever i have questions i try to come to forums where people may work in the industry since i don't.

    So here's my problem...and it's one that is common and that is the cooling of a bonus over a garage. I have a bonus that we finished off a couple of years ago and contracted with a local hvac company to add a zone off of our current trane system. We looked at the possibility of doing a mini-split or adding a zone. Since my wife didn't like the looks of the mini split we prefered to add a zone if possible. One company came in and inspected the space and the current system and said it was large enough to handle the additional space so all we needed to do was add the zone and ductwork. We did that and have not been able to get the temp below 86 in the summer. I live in NC and we have many days in the mid 90's and low 100's in the summer and my house faces NW and we have a black roof.

    The area in the bonus is around 350 sq ft runs off the upstairs unit which also cools two upstairs rooms that total around 450 sq ft. So right around 1000 sq ft and it's a trane 1.5 ton system. The company came out last year and replaced the flex vent running through the attic with rigid to get better flow but has not helped. We insulated well and i know bonus rooms are hard to keep cool when they have knee walls and are over a garage.

    My question is, at this point they say they have done everything they can and it looks like we need a larger unit. Shouldn't they have known that when they did the analysis? That should have been in the original quote. With the cost of upgrading the unit, i may have gone with the mini-split. What should i expect from them? I don't want to be unreasonable but i'm not sure what they should be willing to do to make it right.

    The current trane system is 4 years old so i hate to pull it out. I guess i could try to sell it on ebay or something.

    Thanks for your help!

  2. #2
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    You really need a load calculation on the home with the bonus room to see what size system is needed.

    You could add insulation ,tint windows ,etc., to reduce the load,which might make your existing system the correct size,if it isn't already.

    Check the walls and floor of the bonus room for insulation.Be sure hot attic air can't travel under the bonus room floor,this could be the problem,I've seen it many times.

    As far as what the contractor's responsibility is,hard to say from here,at the most adjust the price of a mini-split or larger unit ,by near the amount adding the zone cost and remove the zoning.

  3. #3
    Thanks for the reply! Come to think of it, i'm not sure they replaced the barriers at the end of each floor joist when they blew the insulation in. I'll double check that to make sure.

    Is there a blower that could be installed midway in the run that could help push more air out to that bonus room?

  4. #4
    Join Date
    Mar 2005
    Location
    Houston, Texas
    Posts
    11,874
    Quote Originally Posted by johnnyb321 View Post

    Is there a blower that could be installed midway in the run that could help push more air out to that bonus room?
    Yes,it's called a booster fan. But they usually don't do what you want them to do.Your contractor really needs to work with you on this problem. As dash said,get a load calc done before you do anything else.

  5. #5
    Join Date
    Dec 2007
    Location
    Cedar Grove, Wi-Sheboygan
    Posts
    1,582
    Where's the equipment in relation to the bonus room? I can't see any reason why you can not heat or cool this room along with the other 2 rooms upsrairs with a 1-1/2ton unit. If there's a vapor barrier in the ceiling of the garage along with insulation in the ceiling and insualtion in the knee walls as well as the ceiling in the attic it may just be in need of a larger trunk run to that area with a couple of 6" runs to the bonus room to supply the room with enough air flow. Did they put a return air vents in the bonus room ? or do you have any return air vents at all upstairs ? That could be part of the problem.

  6. #6
    Quote Originally Posted by DanW13 View Post
    Where's the equipment in relation to the bonus room? If there's a vapor barrier in the ceiling of the garage along with insulation in the ceiling and insualtion in the knee walls as well as the ceiling in the attic it may just be in need of a larger trunk run to that area with a couple of 6" runs to the bonus room to supply the room with enough air flow. Did they put a return air vents in the bonus room ? or do you have any return air vents at all upstairs ? That could be part of the problem.
    Thanks for the replies...I don't think they put a vapor barrier up before they sheet rocked the garage. They did blow fiberglass insulation in the cavity's between each joist, which are around 12 inches tall. I looked last night and they did not replace the plywood at the end of the joists on one side so I need to nail those back in. Could that alone solve my problem?

    I do have a return in tha bonus and the run is around 40-50ft i guess. They did replace the flex line with rigid but i'm not sure what size they put in. There is another return in the upstairs as well. The upstairs space and the bonus are not joined though...the bonus is a seperate space.

    Should the load calc have been done by the contractor when he gave an estimate? I was not there but my wife said he spent a good deal of time up in the attic and in the bonus.

    Thanks

  7. #7
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,369
    You're down to three considerations:

    1. Reduce heat gain on bonus room, meaning consider radiant barrier for roof deck, and be sure space between bonus room floor and garage ceiling is insulated

    2. Increase amount of air into bonus room, and ensure bonus room has adequate return air provision to upstairs central system

    3. If increase of airflow and improved efforts to reduce heat gain fail, either a mini-split or a larger upstairs system are in order. I would opt for the mini-split, since your existing Trane equipment is pretty young

  8. #8
    Join Date
    Feb 2006
    Location
    Tn.
    Posts
    1,344
    you should have went with a seperate system for the bonus room itself to begin with.
    Only reason I see you did it this way was to save money ,and it backfired on you.
    Did anyone bid on a seperate split system for your bonus room?

    Leave the other unit in place and get a seperate split for that room.

  9. #9
    Quote Originally Posted by m-cooling View Post
    you should have went with a seperate system for the bonus room itself to begin with.
    Only reason I see you did it this way was to save money ,and it backfired on you.
    I did get a couple of quotes from companies that said i could run a zone off of the existing unit and i went with one of them. I had a company that also quoted a mitsubishi mini split and the costs were about the same. We went with the zone because of the looks of the minisplit sitting in the wall not the cost of the system.

    Perhaps i should have visited this site prior to signing a contract so i could get some good feedback on what to do rather than rely on the expertise of my local HVAC companies.

  10. #10
    Join Date
    Feb 2006
    Location
    Tn.
    Posts
    1,344
    I'm not talking about a ductless mini split.

    Look I've seen it hundreds of times.The builder puts 1 system in and wants to run what we call a "riser" up to the bonus room or up to the upstairs and it NEVER works right.It's a way for the house builder to save money and not buy another unit and then when the people buy the house ,they have to deal with it then.You probably won't notice untill the summertime.

    If I had a 2 story house with a bonus ,I would have 3 different systems.
    1 downstairs -1 upstairs-and 1 for the bonus.

    Zone dampers could work in some cases ,but obviously not in yours.

  11. #11
    Join Date
    Feb 2006
    Location
    Tn.
    Posts
    1,344
    you need somebody to put the pen to paper instead of just measuring sq. footage and guessing at what you need.Like Dash said

  12. #12
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    Provided that the equipment and ductwork are sized properly, you shouldn't be experiencing any problems.

    Insulation is a big factor. If you don't have enough b/t the garage and bonus, then you are gaining a lot of heat out of your garage. Same deal with kneewalls and attics.

    I would recommend that you call the contractor and ask to see the load calculation. They should still have it. If they don't, then start asking why.

    If a load wasn't done, then well your kinda done for. Its your responsibility to make sure you hire the right contractor. There are no codes that will save you.


    Another thing......have they come to see if the zone system is operating properly? Did they install a bypass in the ductwork? How big is it? How long is it?

    They need to be 100% sure that zone system is working properly. If the bypass is not set properly, static pressure will build up. If the bypass is not long enough or not installed properly, there's a good chance either the coil is freezing up or the Discharge Air Temp. Sensor is cutting out the compressor once the coil gets too cold, which in short is just recycling air until the coil temp rises.
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  13. #13
    Thanks for the replies! I think, like a lot of homeowners, that the company coming in would do whatever it needed to make sure what they install is going to do the job. I should have done more homework up front to determine what a load calc was and make sure it was done. In fact i should have researched this when the builder was building the house and told him to put a seperate unti in just for the bonus.

    I'll check with them about the size of the bypass and if the coil could be freezing up. They have been out to check the system and install rigid ductwork so i assume it's working properly, but i'll ask again. I'll get in behind the knee wall tonight and check the insulation again.

    I assume there are companies that will come out and check what you have and see if it's enough or done right. Do a load calc and rule out everything but the HVAC. Perhaps use a infared camera to see where the heat is coming in from?

    Thanks again for all the good advice...I wish i had come out here before all of this.

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