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whole house fan

Post in 'The Green Room' started by amellefson, Jan 30, 2011.

  1. Seasoned Oak

    Seasoned Oak Minister of Fire

    Joined:
    Oct 17, 2008
    Messages:
    3,721
    Loc:
    Eastern Central PA
    Make sure you have enough exhaust vents above the fan to handle the large volume of air expelled. We can almost make it through the entire summer without using any AC just by cooling down the house overnight and shutting off the fan in the morning. By the time the house starts to heat up again its already evening,time to run the fan again. Works good here in central PA. Only when we have very warm nights do we need AC.

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  2. btuser

    btuser Minister of Fire

    Joined:
    Jan 15, 2009
    Messages:
    2,030
    Loc:
    Principality of Pontinha
    I've seen it used as a vapor barrier but I have to put myself in the no camp when it comes to the radiant barrier believers. Just a thin layer of plastic or even paper will have a temperature differential of considerable degree when there's no insulation on the backside of it simply by slowing down the convection. It works in space but there's nothing to keep the waves bouncing back in the other direction. I hope it works but it seems like every single home and business would have it already if it really panned out and that's not what I see. Even a ceiling tile grid with open lights and leaky ducts will give you a temp diff of 20 degrees.
  3. woodgeek

    woodgeek Minister of Fire

    Joined:
    Jan 27, 2008
    Messages:
    2,850
    Loc:
    SE PA
    I looked at installing reflectix in my home and pushed the numbers. Installed as recommended, under the rafters,with in the installer performance specs, I might save 10% of my AC bill (assuming my attic is airsealed and insulated)--a low figure b/c of my rather shady lot. Given my low AC bill, this would have been something like $30-40/yr. Obviously not much to get excited about. It also seemed very pricey per sq ft for what ir was--would have cost me several hundred dollars.

    I think in a cooling dominated climate with full sun exposure, it will clearly pay for itself, and I gather it is popular 'down there' in new construction.
  4. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    7,146
    Loc:
    Salem NH
    Hello Woodgeek

    Yes, if your lot is shady already then there is not as much savings in the summer. Although it can still help in the winter with less melting snow and ice dams. See pic below. Left half has foil (project half done) right half is not done yet!

    Also if you do all yourself the cost of materials is relatively cheap. $23.95 per roll. I used only 22 rolls.

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