When the weather is cooling off, you are probably concerned about how you’ll make the most of your heating and cooling. After all, HVAC costs routinely make up a large chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners look closer at their thermostat. Could there be a setting they could use to boost efficiency?
The bulk of thermostats have a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting provide for an HVAC system? This guide can help. We’ll share just what the fan setting is and when you can use it to cut costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For most thermostats, the fan setting indicates that the system's blower fan keeps running. Some furnaces can run at a low level in this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will run the fan during a heating or cooling cycle and switch it off when the cycle is finished.
There are advantages and disadvantages to trying the fan setting on your thermostat, and what's ideal can depend on your personal comfort requirements.
Advantages to trying the Fan/On setting:
- You can keep the temperature in every room more consistent by permitting the fan to keep running.
- Indoor air quality can increase since steady airflow will keep moving airborne pollutants into the air filter.
- A smaller amount of start-stop cycles for the system's fan helps lengthen its life span. Because the air handler is usually a component of the furnace, this means you might avoid needing furnace repair.
Drawbacks to using the Fan/On setting:
- A continuous fan will likely increase your energy bills slightly.
- Constant airflow may 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 may persist in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, forcing the HVAC system to work harder to preserve the preferred temperature. In severe heat, this can lead to needing AC repair more quickly as wear and tear increases.
The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually drift into the rest of your home. Leaving the fan setting on could pump more cold air upward, increasing the amount of heating you need to keep warm.
If you’re still trying to decide if you should try the fan/on setting, keep in mind that every home and family’s comfort needs will vary. Leaving the HVAC system’s fan on might work for you if:
Someone in your household has allergies. Allergies and other respiratory conditions can be hard on the family. Leaving the fan on should help to improve indoor air quality, helping your family breathe easier.
Your home has hot and cold spots. All kinds of homes deal with stubborn hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting should help lessen these changes by steadily refreshing each room’s airflow.