We replaced our furnace last year, and the new one has a fan which can be run independently of the heating function. The fan recirculates air throughout the house. Is there a way to use this to keep the house cool?

It's a two story house with a basement. The basement stays cool year round, and the upstairs gets very warm in the afternoon (no shade trees close enough to shield the upstairs rooms from the sun, unfortunately). We spend the day on the main floor, which is the floor we'd like to cool. All levels have roughly the same volume of space. It seems that if I run the fan, I'll just blend the cool basement air with the hot upstairs air and end with the main living space at the same temperature it was before. But perhaps there's some strategy based on the time of day that I run the fan?

At night we open all the windows and use an exhaust fan to blow warm air out the second storey window, drawing cool air in through the ground floor. As soon as the sun comes up, we close the windows and blinds to keep the cooler air in, and block the sun.

  • Try it. See if it helps. That's the cheap and easy way to answer your own question.
    – Móż
    Jun 10, 2021 at 2:18

2 Answers 2


No, it would be expensive and not effective, it only recirculates air in the house. What works very well is a "whole house fan". It can be located anywhere despite the instructions to centrally locate it. I have one in a utility room at the corner of the house; open windows in rooms that need most air. Of course you are limited to the outside temperature. But I find a half hour in the cool late evening and a half hour in the early morning works very well. Think of ten times more air movement than your window fan. Be sure to get a belt drive ,not a direct drive , Belt drives are quieter because they turn slower but move as much air with bigger blades. My first house in northern Indiana has a fan and no AC and was generally very comfortable. Since then , I have installed them in three houses which shows what I think of them. Also excellent if there is a smoky cooking accident.


There are ways but not without adding to existing systems. When I was in the service our furnaces were just like yours 70’s . We did have swamp coolers, I installed an over ride switch to turn the house fan on. The cool air generated by the swamp cooler was circulated through the home and cooled the upper floor by more than 20 degrees F . (I added the bypass switch to each house on our block shortly after)

There are geothermal coils that can exchange ground water through a coil set and once the water is warmed return it to a second well. The water pump is quite small and the coil was not horribly expensive I put one of these in in the late 90’s it worked quite well for that house.

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