Blower Fan Recommendations

There is a clear difference in how to use the HVAC circulating fan in the summer versus the winter.

Winter: It may be beneficial to continuously run the fan. It may provide more consistent temperatures from room to room.

Summer: It usually is not beneficial to continuously run the fan. This is because each time the A/C cycles off, the process of cooling and dehumidifying air stops within seconds. The continuously running blower fan will evaporate the already-collected water back into the air. Had the fan cycled off, the water would have had the chance to run into the drain. This process happens over and over again when the fan runs continuously, and up to a half-gallon of water can be re-evaporated each time.

So, what can happen when the fan runs continuously in the summer?

• Comfort suffers. A humid home is not a comfortable home. We call it the “cave effect” because no matter how low you drive down the temperature, you still feel sticky.
• Mold growth, dust mites, insects and spiders, and other allergy and asthma triggers are encouraged to thrive.
• Utility bills will be impacted. It takes more energy to condense water than it does to cool the air.

If a home suffers from rooms that over-cool or don’t cool properly, there is a problem that needs to be addressed. Continuous fan operation is usually the wrong solution.