Set thermostat to “on” or “auto”

Which thermostat setting costs more money? Should I set thermostat to “on” or “auto”? Almost every thermostat features separate controls for heating and air conditioning. You set to “heat” when you want to heat, “cool” when you want to cool and “off” for those few months where you don’t need either.

But what about the fan? There are pros and cons for each setting and there is a lot of confusion about which setting to choose. Read the following and decide which works best for you.

Set fan to “on”

Pros – When the fan is on, the air is being pulled through your filtration system, cleaning it. If the fan isn’t on, these systems designed to purify your air cannot be utilized. Keeping the fan on also means more even distribution of your heating and cooling. Less starts and stops of the fan may help it last longer.

Cons – Expensive! Unless you have a variable speed motor and your fan is running continuously, you are paying for that electricity. The filter will also need to be changed more.

Set fan to “auto”

Pros – The auto setting means less energy usage, because the fan will run for the least amount of time and at the lowest speed to keep your space heated or cooled. Your filter will also last longer.

Cons – There is less even distribution of heating and cooling. Once the thermostat is satisfied, the fan shuts off. More stops and starts can wear out the fan quicker.

Some newer thermostats have a “circulate” option that allows you to set the fan to run for a certain amount of time per hour. This evens out the hot and cold spots, uses your filtration system, and keeps energy usage from going through the roof.

We hope this gives you the information you need to make an informed decision on whether to set thermostat to “on” or “auto”.