When 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 frequently add up to a big portion of your monthly electric bill. To learn new ways to lower their HVAC bill, some people look closer at their thermostat. Maybe there’s a setting they can use to improve efficiency?
The majority of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what can the fan setting provide for an HVAC system? This guide should help. We’ll review what exactly the fan setting is and whether you can use it to cut costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For the bulk of thermostats, the fan setting means that the system's blower fan keeps running. Some furnaces may continue to generate heat at a low level in this setting, but in most cases heating or cooling isn’t being made. The ‘Auto’ setting, on the other hand, will start the fan over a heating or cooling cycle and shut it off after the cycle is complete.
There are pros and cons to switching on the fan setting on your thermostat, and what's ideal can depend on your personal comfort needs.
Advantages to switching to the Fan/On setting:
- You can keep the temperature throughout your home more uniform by allowing the fan to keep generating airflow.
- Indoor air quality should improve as steady airflow will keep passing airborne pollutants through the air filter.
- A smaller number of start-stop cycles for the blower fan helps expand its life span. As the air handler is often part of the furnace, this means you could avoid needing furnace repair.
Drawbacks to using the Fan/On setting:
- A constant fan can raise your energy expenses somewhat.
- Nonstop airflow could clog your air filter in a shorter amount of time, increasing the frequency you’ll need to replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
Through the summer, warm air can persist in unfinished spaces including 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, pushing the HVAC system to work more to keep up with the desired temperature. In extreme heat, this could lead to needing AC repair more often as wear and tear increases.
The reverse can occur over the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually make its way into the rest of your home. Leaving the fan setting on may pull more cold air upward, increasing the amount of heating you need to remain warm.
If you’re still trying to figure out if you should switch to the fan/on setting, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on might be ideal for you if:
Someone in your household has allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on should help to increase 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 evolve 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.