Answered: Should My Thermostat Be on Auto or Fan?

Once the weather starts to cool off, you may be thinking about how you’ll prepare your heating and cooling. After all, HVAC bills frequently make up a big chunk of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Could there be a setting they can use to boost efficiency?

Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what does the fan setting offer for an HVAC system? This guide can help. We’ll walk through just what the fan setting is and how you can use it to cut costs in the summer or winter.

My Thermostat Has a Fan Setting?

For the majority of thermostats, the fan setting indicates that the air handler’s blower fan keeps running. A few furnaces can generate heat at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and shut it off after the cycle is finished.

There are benefits and drawbacks to trying the fan setting on your thermostat, and what’s ideal {will|can|should]] depend on your unique comfort requirements.

Advantages to using the Fan/On setting:

• You can keep the temperature throughout your home more consistent by permitting the fan to keep running.
• Indoor air quality should improve since continuous airflow will keep moving airborne contaminants through the air filter.
• A smaller number of start-stop cycles for the blower fan helps extend its life span. Since the air handler is typically connected to the furnace, this means you could avoid needing furnace repair.

Disadvantages to using the Fan/On setting:

• A continuous fan will likely raise your energy costs by a small margin.
• Constant airflow may clog your air filter up more quickly, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Each Season

Through the summer, warm air can linger in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system can gradually move this warm air into the rest of your home, pushing the HVAC system to work harder to preserve the set temperature. In serious heat, this can lead to needing AC repair more quickly as wear and tear increases.

The opposite can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually make its way into the rest of your home. Leaving the fan running could pull more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to determine if you should try the fan/on setting, remember that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on might be best for you if:

Someone in your household suffers from allergies. Allergies and similar respiratory conditions can be stressful on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.

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