As the weather is cooling off, you are probably wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC expenses routinely contribute a significant portion of your monthly electric bill. To figure out new ways to reduce costs, some people look closer at their thermostat. Could there be a setting they should use to increase efficiency?
The majority of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a regular cycle, what can 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 reduce costs during 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. A few furnaces may continue to run at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan over a heating or cooling cycle and switch it off once the cycle is over.
There are pros and cons to using the fan setting on your thermostat, and what's ideal should depend on your personal comfort preferences.
Advantages to using the Fan/On setting:
- You can keep the temperature in every room more balanced by allowing the fan to keep generating airflow.
- Indoor air quality should improve as steady airflow will keep moving airborne pollutants through the air filter.
- A smaller number of start-stop cycles for the system's fan helps extend its life span. Since the air handler is usually a component of the furnace, this means you might avoid needing furnace repair.
Downsides to switching to the Fan/On setting:
- A constant fan will likely raise your energy expenses somewhat.
- Nonstop airflow can clog your air filter soon, increasing the frequency you will want to replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
In the summer, warm air can linger in unfinished spaces such as the attic or an attached garage. If you keep the fan running, your HVAC system may gradually move this warm air into the rest of your home, forcing the HVAC system to work more to keep up with the preferred temperature. In severe heat, this may result in needing AC repair more regularly as wear and tear gets worse.
The opposite can happen in the winter. Cooler spaces like a basement will hold onto cooler air, which may eventually flow into the rest of your home. Leaving the fan setting on may draw more cold air upward, increasing the amount of heating you need to stay warm.
If you’re still trying to decide if you should switch to 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 might be best for you if:
Someone in your household has allergies. Allergies and similar 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 experiences hot and cold spots. Lots of homes deal with persistent hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help limit these changes by constantly refreshing each room’s ventilation.