Once the weather is cooling off, you might be thinking about how you’ll make the most of your heating and cooling. After all, HVAC bills routinely add up to a big piece of your monthly electric bill. To try and find ways to save, some homeowners take a closer look at their thermostat. Could there be a setting they should use to improve efficiency?
The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting offer for an HVAC system? This guide can help. We’ll walk through what exactly the fan setting is and when you can use it to save money over the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting indicates that the system's blower fan stays on. Some furnaces will generate heat at a low level in this setting, but in most cases heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will turn on the fan during a heating or cooling cycle and shut it off once the cycle is complete.
There are benefits and drawbacks to trying the fan setting on your thermostat, and the ideal option should depend on your distinct comfort needs.
Advantages to using the Fan/On setting:
- You can keep the temperature throughout your home more uniform by allowing the fan to keep circulating air.
- Indoor air quality can increase because steady airflow will keep forcing airborne contaminants into the air filter.
- A smaller amount of start-stop cycles for the blower fan helps expand its life span. As the air handler is typically connected to the furnace, this means you can prevent the need for furnace repair.
Downsides to using the Fan/On setting:
- A constant fan can raise your energy costs somewhat.
- Nonstop airflow may clog your air filter up more quickly, increasing the frequency you will want to replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
During the summer, warm air may persist in unfinished spaces such as 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 work harder to preserve the set temperature. In serious heat, this can result in needing AC repair more regularly 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 draw more cold air upward, increasing the amount of heating you need to stay warm.
If you’re still trying to figure out if you should try 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 may be best for you if:
Someone in your household deals with allergies. Allergies and similar respiratory conditions can be tough on the family. Leaving the fan on can help to increase indoor air quality, helping your family breathe easier.
Your home has hot and cold spots. All kinds of homes deal with persistent hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help minimize these changes by constantly refreshing each room’s supply of air.