When the weather starts to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs can contribute a large chunk of your monthly electric bill. To try and find ways to save, some owners look closely at their thermostat. Maybe there’s a setting they can 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 provide for an HVAC system? This guide should help. We’ll review precisely what the fan setting is and how you can use it to save money over the summer or winter.
What Is the Fan Setting on My Thermostat?
For the bulk of thermostats, the fan setting indicates that the air handler’s blower fan remains on. Certain furnaces will generate heat at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and shut it off after the cycle is complete.
There are advantages and disadvantages to switching on the fan setting on your thermostat, and the ideal option can depend on your distinct comfort preferences.
Advantages to using the Fan/On setting:
- You can keep the temperature throughout your home more consistent by allowing the fan to keep generating airflow.
- Indoor air quality should improve as continuous airflow will keep moving airborne particles into the air filter.
- A smaller number of start-stop cycles for the system's fan helps expand its life span. Because the air handler is often connected to the furnace, this means you can avoid needing furnace repair.
Downsides to switching to the Fan/On setting:
- A constant fan could add to your energy costs by a small margin.
- Constant airflow may clog your air filter soon, increasing the frequency you should replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
Through the summer, warm air will sometimes persist 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, forcing the HVAC system to run longer to keep up with the set temperature. In severe heat, this can result in needing AC repair more regularly as wear and tear grows.
The opposite can happen over 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 may 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 are not the same. Leaving the HVAC system’s fan on may work 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 should help to increase indoor air quality, helping your family breathe easier.
Your home experiences hot and cold spots. Lots of homes wrestle with stubborn 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 consistently refreshing each room’s airflow.