I understand That, Did it with Commercial Units Micheal . But it was filtered , Those thing just bring Crap in to add to a home’s Problems. If they where installed in a right matter Like a air exchanger then i see it as a benefit. We did a lot of things in the good old days that will not fly today. Remember asbesto’s , pcb’s in oil transformer and so on.
It is a good idea only designed wrong
Good ole day?
I’ve seen units installed in the last ten years.
As always YMMV:D
still a poor design . LOL I am very stubborn .
Air movement removes the insulating factor of air from your body.
Air movement increases the rate of evaporation of sweat.
Evaporative cooling make you feel cooler.
You can stand a lot hotter indoor air if it is moving and therefor do not have to run the A/C as often…
But that can be done with a regular fan.
No it does not measure, but you can see big and small.
I agree with you.
From the limited perspective of “comfort” which is certainly important and part of what you want to achieve with a whole house fan, breezes feel good on the skin. No one can argue that point.
But when, in order to create this breeze, you are sucking unconditioned air into the home along with all of the relative humidity, pollen, mold, and other pollutants…and the home is either relatively new or has been weatherized to restrict the air from flowing out at the same rate it is flowing in…in my opinion, the value is diminished.
The ultimate objective of energy efficiency is to control as much of the air exfiltrating and infiltrating a home as possible. IMO, the whole house fan is contrary to that objective.
A whole house fan is a regular fan!
What causes heat energy transfer?
Temperature differential.
What increases the rate of heat transfer through the building envelope?
A lower delta T.
When you suck air out of your house, you push excessively hot air out of the attic. You can run the fan for just a few minutes and cool off your entire buildings structure. You can then shut off the fan and the heat won’t just come back.
When you turn on your air conditioner you lower the temperature in the living space which increases the delta T. and accelerates the heat transfer through the ceiling. It may take hours for things to stabilize depending on weather conditions. Not only are you removing heat from the interior of your house but you are pulling it through the ceiling and removing it from the attic as well.
Not very efficient is it?
When I get home from work I use a whole house fan to suck out the hot air that’s been hanging around all day from radiant heat loading, this air is used to cool down the attic buffer zone and when I turn on the air conditioner it’s a matter of minutes before it reaches set point.
Jim, you are not conditioning the air with a whole house fan. You’re simply removing excessively hot air including the indoor air contaminants and replacing it with fresh air. Granted there are natural contaminants in the outdoor air (relative to your location of residence). If we didn’t sterilize ourselves so much we wouldn’t be so susceptible to these outdoor pollutants.
The CFM of air from contaminated areas is insignificant in comparison to the outdoor air dilution rate that is occurring while the fan is in operation.
Even if you were to pull in radon gas into the house from the crawl space, it’s not going to be in the house long enough to degrade.
I am not saying it is a bad idea but needs to be designed better,Why would you bring 80% humidity in to a home and everything else, If you concerned about energy design a good system. Long and short Windows open huge fan running. Noise, pollutants , Moisture , Still makes not a lot of sense. Bard and i suspose many other comapany have a system that mixes the air using Temperature and enthalpy control, How ever the enthalpy goes out to lunch. using temperature and modulating damper system on the existing fan system ( condition air would give the same and cleaner results )
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In actuality, a percentage of the moisture never enters the house because of window screens!
Also, you’re bringing in high relative humidity air but when it mixes with the higher temperatures within the house the relative humidity actually is quite lower.
You use these fans at night or when the temperature falls outdoors. As you cool air, it forces a lot of water vapor out of the air. The relative humidity goes up but when you reheat it by mixing with indoor air, the relative humidity drops.
What I meant with regular fan is a fan that stands up inside you living room and moves air around. I don’t think people install whole house fans just to have air movement but to replace hot air with cooler air.
If used and insulated properly, whole house fans can be very effective. I find that most homeowners that have them don’t ever use them.
It doesn’t matter if I’m conducting a home inspection or energy audit, I educate the client on proper usage, which includes the pros and cons of the fan.
Kevin
Have had whole house fans in my previous two homes (up in CT) and absolutely love them.
Everything I have read and heard for the past 25-30 years have said that the air indoors is much more polluted than outdoors so I don’t see a lot of harm in sucking it all inside.
On those 90++ degree days we would turn it off and turn the A/C on. In winter I had a little Styrofoam cover I made placed over it, usually put it on a week or two after Thanksgiving.
They are great in older homes IMHO (mine were circa 1890 & 1771)…
Al (hermetically sealed with central air now down here) in TN
We have used a whole house fan for fifteen years. We also installed a thermostatically controlled vent in the roof above the attic where the fan is located. It does a good job of cooling our tri-level home. We have radiant heat in the ceiling, so AC would be tough to install (no ductwork).
I think they are a National Hazard of Epic Proportions! 
I like whole house fans, they can save energy by using them sometimes instead of AC. Obviously the attic should have adequate ventilation. Mostly I see them in older homes, very rarely a newer home.