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Repurposing duct system for cooling?

AbelLee Member Posts: 1
I have an old, small house with a hot air system. My basement is very cool in the Summer.
Can I tie into the ductwork with a dedicated fan and move some of that cool air through the ductwork to cool my house? Filters necessary?


  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 6,033
    edited July 2022
    Moving air always feels cooler than still air. Moving air evaporates more perspiration from our skin, making it feel cooler. A couple of questions
    1. Is the duct system still connected to a working heater?
    2. Is the basement air healthy? Mold mildew, or other offensive odors would be unhealthy
    3. Is the basement dry?
    4. Are the ducts clean and free from biologicals?

    If you can answer these questions affirmatively, then perhaps a very low speed blower can gently move some of the cool air from the basement up to the first floor.

    You can remove the return duct from the furnace and perhaps connect a ECM powered blower to the system in some fashion. or perhaps a blower meant for a smaller appliance that moves less air. And YES i would add a filter to the system just before the blower to filter the air and keep the blower clean
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • GW
    GW Member Posts: 4,609
    We do this all the time. Many older dock systems are “good enough“

     If the ducting is super old, then no. It’s a little bit of a relative question you’re asking. How old and clunky is it? For more opinions, snap a few pictures of the ducting. 

    Also, you would probably want to run a dehumidifier, to reduce the condensation forming on the ducks. That’s a different conversation

    But if we’re talking ancient, like dirt-floor ancient, I would pass on that. Too much
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 6,033
    To be clear... You are NOT talking about adding a central AC system to those old ducts. All you want to do is to take the cool basement air and see if it will reduce the first floor temperature a little. Correct me if I misunderstood your query.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • ChrisJ
    ChrisJ Member Posts: 14,946
    edited July 2022
    Even if it's the cleanest, tightest basement on the planet it's only cool because it's below ground and doesn't have much if any heat gain from outside and the ground down lower is cool, but won't be once you start heating it. It's not going to magically produce "cold" to cool a house which is being continuously warmed by the sun and outside air.

    You'll end up with a hot house and a hot basement with even the possibility of condensation all over the foundation walls and the floor. And of course there's also the whole radon thing depending on who you ask.
    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
    JUGHNE Member Posts: 10,785
    Also to consider is the possibility of draft reversal of any chimney you might have for any gas or oil appliances.
    Some have tried to leave the furnace blower door off, bypassing the door safety switch and running the blower. This can pull CO fumes out of the furnace.

    Older neighbor couple had this set up and their CO detector went off early one morning.
    The 911 dispatcher knew I lived across the street and called my landline.

    She had them get out of the house and stay warm in their car....outside of the garage BTW.

    A large return grill on the furnace (which was installed for the very purpose you are inquiring about) had caused the water heater to downdraft the chimney.

    I closed that opening up and no problem since.