Which A/C Fan Setting Cost More, “On” or “Auto”?

Have you ever wondered which fan setting is the best, and most efficient on your thermostat? A common misconception is that leaving the thermostat fan set to “on” uses less electricity. However, Florida Power and Light professionals explain “auto” is the more energy efficient option.

Difference Between “On” and “Auto”

When the thermostat is set to “on” that means the fan is always running, even when it is not heating or cooling your home. When the thermostat is set to “auto”,  you can set your thermostat to the desired temperature and once that temperature is reached the entire system will shut off.


“Auto” is the more energy efficient choice. If you have your thermostat set to “on” it can increase your utility bill. Not only will the “on” setting increase your monthly utility bill, but with the fan running constantly, it can cause your A/C system to fail, costing you even more money in the long run.

Health and Home Benefits

With the “on” setting, your A/C unit runs constantly having less time for the moisture on the unit to drip off and drain outside. That moisture can then be blown back into your home leaving moisture in the air. However, with the “auto” setting your A/C unit has time to allow the moisture to drip off and drain outside, removing that moisture from the air.

This quick tip not only helps you cut down on the cost of utilities, but also helps Ryntal Property Management provide the highest quality properties for our tenants.