Once the weather starts to cool off, you are probably concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can make up a large piece of your monthly electric bill. To try and find ways to reduce costs, some homeowners look closer at their thermostat. Maybe there’s a setting they should use to increase efficiency?

The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what can the fan setting offer for your HVAC system? This guide can help. We’ll share what exactly the fan setting is and whether you can use it to cut costs during the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting signifies that the system's blower fan remains on. A few furnaces will generate heat at a low level in this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will run the fan during a heating or cooling cycle and shut it off once 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 needs.

Advantages to using the Fan/On setting:

  • You can keep the temperature throughout your home more consistent by allowing the fan to keep running.
  • Indoor air quality can increase since continuous airflow will keep passing airborne contaminants through the air filter.
  • Fewer start-stop cycles for the blower fan helps lengthen its life span. As the air handler is usually part of the furnace, this means you might avoid needing furnace repair.

Disadvantages to using the Fan/On setting:

  • A continuous fan will likely raise your energy costs by a small margin.
  • Continuous airflow can clog your air filter soon, 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 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 can draw this warm air into the rest of your home, pushing the HVAC system to run longer to keep up with the set temperature. In extreme heat, this may lead to needing AC repair more regularly as wear and tear grows.

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

If you’re still trying to determine if you should use 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 might work for you if:

Someone in your household deals with allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Lots of homes deal with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting can help minimize these changes by steadily refreshing each room’s ventilation.