Once the weather is cooling off, you are probably wondering about how you’ll prepare your heating and cooling. After all, HVAC costs routinely make up a large chunk of your monthly electric bill. To figure out new ways to save, some people take a closer look at their thermostat. Maybe there’s a setting they could 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 an HVAC system? This guide can help. We’ll share what exactly the fan setting is and whether you can use it to save money during 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 remains on. Some furnaces will run at a low level with this setting, but in general heating or cooling isn’t being made. The ‘Auto’ setting, conversely, will run the fan during a heating or cooling cycle and switch it off after the cycle is over.
There are pros and cons to trying the fan setting on your thermostat, and the ideal option can depend on your unique comfort preferences.
Advantages to trying the Fan/On setting:
- You can keep the temperature in each room more consistent by allowing the fan to keep running.
- Indoor air quality should improve since steady airflow will keep moving airborne contaminants through 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 minimize the risk of needing furnace repair.
Disadvantages to switching to the Fan/On setting:
- A continuous fan will likely increase your energy costs somewhat.
- Continuous airflow can clog your air filter soon, 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 may persist in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system can gradually move this warm air into the rest of your home, pushing the HVAC system to run longer to maintain the set temperature. In serious heat, this could lead to needing AC repair more often as wear and tear grows.
The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually flow into the rest of your home. Leaving the fan running could pull more cold air upward, increasing the amount of heating you need to stay warm.
If you’re still trying to decide 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 could be ideal for you if:
Someone in your household suffers from allergies. Allergies and other 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 shift to a temperature different from the rest of the house. The fan setting should help limit these changes by steadily refreshing each room’s ventilation.