1) it could cost hundreds of dollars per year to run the fan.. But they're figuring it being on 24/7, they even use a refrigerator as the comparison. That's just not going to happen. It'll be on in the summer months, and maybe in the winter months, but likely not even 24/7 during those times. Also, I would assume an efficient fan would take MUCH less energy than starting the compressor. If my compressor starts less frequently I may actually be saving money or zeroing out with less wear on the capacitor and compressor.

2) Ducts in attics might fill with warm air and actually heat up your house. Fair point. Easy to check that....try it and see if that's what happens. I don't have ducts in my attic.

2a) More humidity may be introduced if air is being blown across wet coils. Fair point. Easy to check that....try it and see if that's what happens.

3) Keeping the fan on in the winter may mean cold air comes through the ducts (see 2 above) Fair point. Easy to check that....try it and see if that's what happens.

4) Your filter may clog up quicker. OK, so it's taking dust, dirt, debris and allergens out of the air where my family and I live and sleep. I'm fine with that and am strangely happy to replace dirty filters in my home.


The pros are:
1) more even distribution of heat and cooling in your house. Good, I like that.

2) less frequent starts and stop of the fan reduces it's stress, Ok..minor point, but it's the compressor I'm more concerned about than the squirrel cage fan. I've personally noticed the compressor starts much less frequently, which in turn means less wear and less electrical cost. I've cooled the air in the ducts, and the ducts themselves once already, I want that cold air I paid for...all of it. Blow it to me baby.

Once the temp in the home goes beyond my set point, the A/C is kicking back on whether I like it or not. I'm experiencing longer periods between the thermostat turning the A/C back on.

3) leaving the fan on means cleaner air inside the house. Not a bad thing, even if I have to replace filters more often, but only likely during very hot or very cold periods.