Once the weather begins to cool off, you are probably concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC costs frequently make up a significant piece of your monthly electric bill. To try and find ways to lower their HVAC bill, some owners take a closer look at their thermostat. Is there a setting they should use to improve efficiency?
The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a regular cycle, what does the fan setting offer for the HVAC system? This guide can help. We’ll share just what the fan setting is and when you can use it to cut costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For most thermostats, the fan setting means that the system's blower fan keeps running. Some furnaces can generate heat at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and turn it off once the cycle is over.
There are advantages and disadvantages to using the fan setting on your thermostat, and the ideal option can depend on your unique comfort preferences.
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 should improve since continuous airflow will keep passing airborne pollutants into the air filter.
- A smaller number of start-stop cycles for the blower fan helps extend its life span. Because the air handler is usually part of the furnace, this means you might minimize the risk of needing furnace repair.
Downsides to using the Fan/On setting:
- A nonstop fan will likely increase your energy expenses by a small margin.
- Constant airflow could clog your air filter up more quickly, increasing the frequency you should replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
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 might gradually move this warm air into the rest of your home, compelling the HVAC system to run longer to keep up with the desired temperature. In extreme heat, this could lead to needing AC repair more quickly as wear and tear grows.
The reverse can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan running could pull more cold air upward, increasing the amount of heating you need to keep 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 will vary. Leaving the HVAC system’s fan on may be best for you if:
Someone in your household suffers from allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on should help to enhance indoor air quality, helping your family breathe easier.
Your home deals with hot and cold spots. All kinds of homes wrestle with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help minimize these changes by steadily refreshing each room’s supply of air.