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  1. #1

    New HVAC, pressure tests, IAQ

    Folks:

    We're completing a renovation of a 100 year old home (to the studs). We put in the new HVAC system including all new duck works (sheet metal ducts, looks like quality work, all done by the tradesmen themselves). The HVAC company is a very old, long standing company with a great reputation. But, they do not perform a pressure test on the system unless I push for it (and pay an extra $800).

    For IAQ reasons, I want to make sure no air from the basement or garage (where the furnace is) makes its way into the house and that there is a slightly positive pressure in the house. We do have up to 20% outside air as part of the return/fresh air supply.

    Any thoughts on the need for a pressure test on the system, how-to assure no air from the garage gets into the house and that a positive pressure is maintained in the home would be greatly appreciated.

    Thanks!!

    Andrew

  2. #2
    Join Date
    Jul 2007
    Location
    Delaware
    Posts
    3,823
    If you want a positive pressure in the home, where are they getting the extra air from. A fresh air vent? You need to pump more air in than you are returning. I (just me) hate any unit in the garage.

  3. #3
    Join Date
    Aug 2007
    Location
    WI
    Posts
    1,094
    Quote Originally Posted by energy star View Post
    I (just me) hate any unit in the garage.
    Not just you. I can't even believe that is legal. It's not here.

  4. #4
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,064
    Quote Originally Posted by andrew1cohen View Post
    Folks:

    We're
    For IAQ reasons, I want to make sure no air from the basement or garage (where the furnace is) makes its way into the house and that there is a slightly positive pressure in the house. We do have up to 20% outside air as part of the return/fresh air supply.

    Andrew
    Dream on! The pressure from wind and stack effect will overcome any attempt to stop air movement throughout the structure. Best to keep the connected space clean of pollution. Providing a small amount of fresj make-up air to purge indoor pollutants and renew oxygen when occupied is a better solution. Always maintain <50%RH through all space to prevent mold growth espicially the basement. Green grass climates require supplemental dehumidification during the low/no cooling load weather to maintain <50%RH. Consider a ventilating dehumidifier to provide all of the above. High efficiency v dehus are less costly to operate. Dehu TB

  5. #5
    What sort of tests will the HVAC contractor perform for that price?

    I paid less than half that to a HVAC co that specializes in airflow issues and got a nearly 3 hrs blower door test, pressure pan, flow hood, home/room pressures, and a thermal image scan of my entire home.

    I found all of the above tests useful as a new HVAC owner as you really don't know how good a job the contractor did till all the numbers are evaluated. Another useful test is the HVAC static pressure which my contractor did only after weeks of phone calls.

    Companies that do the above tests are usual very few and often don't do installs so you should find out exactly what you're getting for your $$$.

    Also, what sort of HVAC equip did you have installed?

    Quote Originally Posted by andrew1cohen View Post
    Folks:

    We're completing a renovation of a 100 year old home (to the studs). We put in the new HVAC system including all new duck works (sheet metal ducts, looks like quality work, all done by the tradesmen themselves). The HVAC company is a very old, long standing company with a great reputation. But, they do not perform a pressure test on the system unless I push for it (and pay an extra $800).

    For IAQ reasons, I want to make sure no air from the basement or garage (where the furnace is) makes its way into the house and that there is a slightly positive pressure in the house. We do have up to 20% outside air as part of the return/fresh air supply.

    Any thoughts on the need for a pressure test on the system, how-to assure no air from the garage gets into the house and that a positive pressure is maintained in the home would be greatly appreciated.

    Thanks!!

    Andrew

  6. #6
    Join Date
    Jul 2007
    Location
    Delaware
    Posts
    3,823
    Do not pay, wait forum rules..........I would get another quote from another company to come in and pressure test the duct. You may just want to have the company just seal the duct as the should in the first place. Also, you could look the system over and tape or use mastic to seal it yourself. I think the reason the one company is so high is because they might be subbing that job out.

  7. #7
    Join Date
    Mar 2005
    Posts
    997
    I didn't think that price was to bad!

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