As the weather begins to cool off, you are probably thinking about how you’ll prepare your heating and cooling. After all, HVAC bills can add up to a large chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners take a closer look at their thermostat. Is there a setting they can use to improve efficiency?

Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what does the fan setting provide for an HVAC system? This guide should help. We’ll review just what the fan setting is and when you can use it to cut costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For most thermostats, the fan setting means that the system’s blower fan stays on. Some furnaces will generate heat at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will start the fan over a heating or cooling cycle and switch it off after the cycle is over.

There are pros and cons to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature throughout your home more uniform by permitting the fan to keep generating airflow.
  • Indoor air quality can increase as continuous airflow will keep moving airborne contaminants into the air filter.
  • Fewer start-stop cycles for the blower fan helps lengthen its life span. Because the air handler is usually a component of the furnace, this means you might prevent the need for furnace repair.

Disadvantages to using the Fan/On setting:

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

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

In the summer, warm air may linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system might draw this warm air into the rest of your home, forcing the HVAC system to work more to preserve the desired temperature. In serious heat, this can result in needing AC repair more often as wear and tear grows.

The opposite can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on will sometimes pump more cold air upward, increasing the amount of heating you need to remain warm.

If you’re still trying to decide 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 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. Many homes deal with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help limit these changes by consistently refreshing each room’s ventilation.