As the weather begins to cool off, you might be wondering about how you’ll take full advantage of your heating and cooling. After all, HVAC bills frequently contribute a large portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some owners take a closer look at their thermostat. Maybe there’s a setting they could use to increase efficiency?
The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a normal cycle, what will the fan setting provide for your HVAC system? This guide should help. We’ll review what exactly the fan setting is and when you can use it to reduce costs in the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting signifies that the system's blower fan stays on. Certain furnaces may continue to run at a low level in this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will run the fan through a heating or cooling cycle and switch it off once the cycle is complete.
There are advantages and disadvantages to using the fan setting on your thermostat, and what's ideal should depend on your unique comfort preferences.
Advantages to switching to the Fan/On setting:
- You can keep the temperature in every room more uniform by enabling the fan to keep circulating air.
- Indoor air quality should improve since constant airflow will keep passing airborne contaminants through the air filter.
- A smaller number of start-stop cycles for the blower fan helps lengthen its life span. Since the air handler is usually a component of the furnace, this means you could prevent the need for furnace repair.
Drawbacks to switching to the Fan/On setting:
- A nonstop fan will likely raise your energy expenses slightly.
- Constant airflow could clog your air filter up more quickly, increasing the frequency you’ll need to replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
In the summer, warm air will sometimes persist in unfinished spaces like the attic or an attached garage. If you use the fan setting, your HVAC system might pull this warm air into the rest of your home, compelling the HVAC system to work more to preserve the preferred temperature. In extreme heat, this can result in needing AC repair more regularly as wear and tear increases.
The reverse can happen during the winter. Cooler spaces such as a basement will hold onto cooler air, which may eventually make its way into the rest of your home. Keeping the fan on will sometimes 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, keep in mind that every home and family’s comfort needs are different. 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 is more likely to enhance indoor air quality, helping your family breathe easier.
Your home experiences hot and cold spots. Lots of homes wrestle with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help minimize these changes by consistently refreshing each room’s supply of air.