As the weather begins to cool off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC costs routinely make up a large piece 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 can use to increase efficiency?
Most thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what does the fan setting provide for your HVAC system? This guide can help. We’ll walk through just what the fan setting is and when you can use it to reduce costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting indicates that the air handler’s blower fan stays on. Some furnaces will generate heat at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan through a heating or cooling cycle and shut it off when the cycle is complete.
There are pros and cons to using the fan setting on your thermostat, and whether you do or don’t can depend on your distinct comfort preferences.
Advantages to using the Fan/On setting:
- You can keep the temperature in each room more uniform by permitting the fan to keep running.
- Indoor air quality can increase because constant airflow will keep passing 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 usually part of the furnace, this means you might prevent the need for furnace repair.
Downsides to switching to the Fan/On setting:
- A constant fan will likely increase your energy bills slightly.
- Nonstop airflow could 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
During the summer, warm air will sometimes linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system might draw this warm air into the rest of your home, compelling the HVAC system to work harder to maintain the preferred temperature. In serious heat, this can lead to needing AC repair more regularly as wear and tear increases.
The opposite can take place 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 setting on 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, don’t forget that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on may work for you if:
Someone in your household deals with allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.
Your home has hot and cold spots. All kinds of homes deal with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help limit these changes by consistently refreshing each room’s ventilation.