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  1. #1
    Join Date
    Apr 2011
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    2

    Unhappy 2nd floor hot main floor hvac, better airflow?

    We have an old two story brick home approx 900 sqft each floor. The hvac in the basement services the main floor directly and does it fine and probably extra capacity howe er the 2nd floor always heats up quickly and is difficult to cool down. We have a window unit for our bdrm up there and plenty of insulation and one of those radiant blankets on the attic rafters. How could we suck some of that cool main floor air up to the 2nd floor? Have a pretty open staircase btween the two and it moves up there a little but still wqrm n stuffy even on 75 degree day. Unfortunately all the walls are closed up after it was renovated b4 we moved in two years ago so ducts from the basement unit would b tough.

  2. #2
    Join Date
    Jul 2009
    Location
    Northeast
    Posts
    661

    Default Re: 2nd floor hot main floor hvac, better airflow?

    First off heat rises so it's going to go to the second floor also the sun beats down and heats up the second. If you don't have any ductwork up there you could put an air handler in the attic and run new duct with another condenser outdoors. Or you could go with a multi evap Ductless, Mitsubishi, Sanyo, etc. Most HVAC Contractors install a particular one. Or you could have a whole house exhaust installed in the attic to pull some of the heat out of upstairs. Good Luck

  3. #3
    Join Date
    Apr 2011
    Posts
    11

    Default Re: 2nd floor hot main floor hvac, better airflow?

    Main question is what size is the a/c for the 2nd floor? you can find out by finding the model number on the ac coil and take the number and divid by 12 (example ּ07-4TXCD061BC3HC)
    take the 61 in the model divide by 12 and you have a 5 ton cooling system if its a 43 divide by 12 its a 3.5 ton ect...

    Search google for a central a/c sizing calculator to see what your 2nd floor needs for cooling.

    If you have a 35'x25' 2nd floor with an open stairway to lower floor and depending on how many windows and the R value of your insulation. You will need roughly a 2 ton cooling system.

    Sounds like you have an under sized cooling system for your second floor. Just like the 1st post stated heat does rise and cold sinks so if you have an open stairway, all the 1st floor heat will rise up and the 2nd floor cooling is going to drop down. Also keep in mind it is alway harder to cool then it is to heat an area.

    A lot of the systems, at least in new england are undersized and or have under sized duct work. you can try to switch your T-stat's fan setting from auto to on to help circulate are though out the house. An attic fan will help pull the heat out of the 2nd floor and also help pull some cooling from the 1st floor


    Good Luck!
    Last edited by JLMCDANIEL; 04-30-2011 at 08:14 PM. Reason: User violation

  4. #4
    Join Date
    Jul 2009
    Location
    Northeast
    Posts
    661

    Default Re: 2nd floor hot main floor hvac, better airflow?

    Quote Originally Posted by MasterPlumber View Post
    Main question is what size is the a/c for the 2nd floor? you can find out by finding the model number on the ac coil and take the number and divid by 12 (example ּ07-4TXCD061BC3HC)
    take the 61 in the model divide by 12 and you have a 5 ton cooling system if its a 43 divide by 12 its a 3.5 ton ect...

    Search google for a central a/c sizing calculator to see what your 2nd floor needs for cooling.

    If you have a 35'x25' 2nd floor with an open stairway to lower floor and depending on how many windows and the R value of your insulation. You will need roughly a 2 ton cooling system.

    Sounds like you have an under sized cooling system for your second floor. Just like the 1st post stated heat does rise and cold sinks so if you have an open stairway, all the 1st floor heat will rise up and the 2nd floor cooling is going to drop down. Also keep in mind it is alway harder to cool then it is to heat an area.

    A lot of the systems, at least in new england are undersized and or have under sized duct work. you can try to switch your T-stat's fan setting from auto to on to help circulate are though out the house. An attic fan will help pull the heat out of the 2nd floor and also help pull some cooling from the 1st floor


    Good Luck!

    I don't think they have anything but a window unit up on the second right now, at least that's the way I read it

  5. #5
    Join Date
    Apr 2011
    Posts
    2

    Default Re: 2nd floor hot main floor hvac, better airflow?

    that is partially right we have an old unit in attic and all the ductwork but non functioning hence i left it out of the equation, i guess i will have to wait and see but just wondering if we first added ac to the basement serving the main floor how bad the 2nd floor would get, looking for most bang for the buck weighing in general comfort since most time outside sleeping and in the office here n there is spent on the main floor.......how difficult/big a job is adding a whole house attic fan? are tthere smaller alternatives? my last house a ranch had one and was wonderful

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