As the weather starts to cool off, you may be concerned about how you’ll prepare your heating and cooling. After all, HVAC bills frequently add up to a significant chunk of your monthly electric bill. To try and find ways to save, some people take a closer look at their thermostat. Is there a setting they should use to increase efficiency?
The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a typical cycle, what does the fan setting offer for the HVAC system? This guide can help. We’ll walk through precisely 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 the bulk of thermostats, the fan setting signifies that the system's blower fan keeps running. A few furnaces will generate heat at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, on the other hand, will run the fan during a heating or cooling cycle and shut it off once the cycle is complete.
There are benefits and drawbacks to switching on the fan setting on your thermostat, and whether you do or don’t can depend on your unique comfort preferences.
Advantages to using the Fan/On setting:
- You can keep the temperature throughout your home more balanced by permitting the fan to keep generating airflow.
- Indoor air quality will be highest because constant airflow will keep forcing airborne contaminants into the air filter.
- A smaller amount of start-stop cycles for the system's fan helps lengthen its life span. Since the air handler is usually part of the furnace, this means you might minimize the risk of needing furnace repair.
Downsides to switching to the Fan/On setting:
- A constant fan will likely add to your energy expenses somewhat.
- 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
In the summer, warm air may persist in unfinished spaces including the attic or an attached garage. If you use the fan setting, your HVAC system might gradually move this warm air into the rest of your home, compelling the HVAC system to work more to preserve the set temperature. In severe heat, this may result in needing AC repair more quickly as wear and tear increases.
The opposite can take place 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 running could draw more cold air upward, increasing the amount of heating you need to keep warm.
If you’re still trying to determine if you should use 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 has allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on should help to improve indoor air quality, helping your family breathe easier.
Your home experiences hot and cold spots. All kinds of homes wrestle with persistent 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 consistently refreshing each room’s ventilation.