Solved: Should My Thermostat Run on Auto or Fan?

Once the weather is cooling off, you may be wondering about how you’ll make the most of your heating and cooling. After all, HVAC expenses frequently make up a big portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some people look closer at their thermostat. Maybe there’s a setting they can use to improve efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what will the fan setting offer for an HVAC system? This guide will help. We’ll review precisely what the fan setting is and how you can use it to save money over the summer or winter.

What Is the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting indicates that the air handler’s blower fan keeps running. Some furnaces may continue to generate heat at a low level in this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, in contrast, will run the fan during a heating or cooling cycle and turn it off after the cycle is finished.

There are advantages and disadvantages to switching on the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your distinct comfort needs.

Advantages to trying the Fan/On setting:

• You can keep the temperature in every room more balanced by allowing the fan to keep running.
• Indoor air quality can increase because steady airflow will keep forcing airborne contaminants into the air filter.
• Fewer start-stop cycles for the HVAC fan helps extend its life span. Since the air handler is often connected to the furnace, this means you can prevent the need for furnace repair.

Downsides to switching to the Fan/On setting:

• A constant fan could raise your energy bills somewhat.
• Continuous airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.

Which Setting for My Thermostat? Fan or Auto in Summer/Winter

Through the summer, warm air will sometimes linger in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system might pull this warm air into the rest of your home, pushing the HVAC system to work harder to maintain the preferred temperature. In severe heat, this could lead to needing AC repair more often as wear and tear increases.

The reverse can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually drift into the rest of your home. Keeping the fan on may pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to determine if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on could be ideal for you if:

Someone in your household has allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on can help to improve indoor air quality, helping your family breathe easier.

Your home deals with hot and cold spots. Many homes wrestle with stubborn hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting might help lessen these changes by consistently refreshing each room’s ventilation.