They are terribly energy inefficient. All your AC is pulled thru the lovers all day long due to stack effect.
And at night, you turn it on with a timer which isn’t too bad, but the AC loss resurfaces the next morning.
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I just assumed most people with these fans didn’t have central AC, or maybe any AC. And that was probably the case back in the day. But if AC has been added, may want to decommission this thing permanently. Or at least have a simple way to seal it off when the AC is on.
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We had both a whole house fan and AC when I was a kid. The AC was a luxury for a few hours during the day.
I don’t see how the fans would align in a modern home except in mild climate areas.
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When I was a kid, we had AC. But we used the whole house fan if the temps were under a certain degree. I have no idea what that is now. Probably somewhere around 78-80ish. It was pretty short lived once the effects of the 70’s energy crisis went away.
The way that the whole house fan is supposed to work is that you open up the house after dark. You run the fan all night to draw in the cool air. When you wake up, you shut off the fan and close all the windows and blinds. This is supposed to keep the home reasonable until bedtime.
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Morning, Joseph! Hope to find you well and in good spirits.
Welcome to the InterNACHI forum. Don’t be a stranger.
I am under the opinion, unlike many of the inspectors that have posted and had indoor circulating fans exhausting, forcing the inside atmosphere into an attic, may/can at times introduce excessive moisture, which can lead to condensation, rot, and mold growth on wood and insulation in the attic assemble.
I would recommend a licensed HVAC ducting company further evaluate and seal the ceiling fan assembly, at the drywall, and install a sheet metal duct work atop the attic fan that leads directly to the outdoors via the roof. The termination point be one way as not to allow exterior atmosphere or birds or rodents into the venting system.
That’s my wag.
I have installed a few and they work awesome if the nights get below a comfortable temperature.
There are now quiet versions that are easily on and talking can happen without a 747 engine sound above your head. I always installed them with a speed control for high and low, and a countdown timer…
I refer to them as a “poor man’s AC”, but they are awesome in the right climate with pulling a draft through a few open windows, so long as you also have adequate attic venting to handle the air flow.
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No. You’re not talking about the applicable ventilation system.
Actually, for your information about past things we used to do, Whole House fans should be required for energy efficiency!
- You’re pulling hot air out of the living space of the house. But today we just keep the A/C running all the time. Real efficient.
- The air from the house purges heat out of the attic. This lowers the temperature differential between inside the house and the attic. Q=U*A*Delta T. Meaning, for every degree differential between the spaces, equals one multiplier in the rate of heat transfer into the house. Not efficient.
- House fans cool the interior of walls, so the HVAC doesn’t have to.
- With the fan running, you can handle about 8 degrees higher temps before you feel like turning on the A/C.
- Fan takes 1/8th the Amperage than that of an HVAC unit.
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