Once the weather starts to cool off, you may be wondering about how you’ll make the most of your heating and cooling. After all, HVAC bills can add up to a big piece of your monthly electric bill. To figure out new ways to lower their HVAC bill, some owners look closely at their thermostat. Maybe there’s a setting they could use to increase efficiency?

Most thermostats have 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 should help. We’ll share just what the fan setting is and how you can use it to save money in the summer or winter.

My Thermostat Has a Fan Setting?

For the majority of thermostats, the fan setting means that the air handler’s blower fan remains on. A few furnaces can generate heat at a low level in 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 turn it off when the cycle is over.

There are pros and cons to switching on the fan setting on your thermostat, and the ideal option {will|can|should]] depend on your personal comfort preferences.

Advantages to trying the Fan/On setting:

  • You can keep the temperature in every room more uniform by allowing the fan to keep circulating air.
  • Indoor air quality can increase since continuous airflow will keep moving airborne contaminants into the air filter.
  • Fewer start-stop cycles for the blower fan helps lengthen its life span. As the air handler is often part of the furnace, this means you could minimize the risk of needing furnace repair.

Downsides to switching to the Fan/On setting:

  • A constant fan will likely increase your energy expenses by a small margin.
  • Nonstop airflow can clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.

Which Setting for My Thermostat? Fan or Auto in Each Season

In the summer, warm air will sometimes stick around 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 preferred temperature. In extreme heat, this could lead to needing AC repair more regularly as wear and tear increases.

The opposite can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan running may 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 use the fan/on setting, keep in mind 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 suffers from allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Many homes wrestle with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help lessen these changes by steadily refreshing each room’s supply of air.