Once the weather is cooling off, you might be concerned about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can contribute a big portion of your monthly electric bill. To try and find ways to lower their HVAC bill, some homeowners look closely at their thermostat. Maybe there’s a setting they could use to increase efficiency?
The bulk of thermostats include both a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting offer for an HVAC system? This guide will help. We’ll review what exactly the fan setting is and whether you can use it to reduce costs over the summer or winter.
What Is the Fan Setting on My Thermostat?
For most thermostats, the fan setting signifies that the system's blower fan keeps running. A few furnaces can run at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, conversely, will run the fan through a heating or cooling cycle and turn it off when the cycle is finished.
There are advantages and disadvantages to trying the fan setting on your thermostat, and whether you do or don’t can depend on your personal comfort preferences.
Advantages to switching to the Fan/On setting:
- You can keep the temperature in each room more balanced by allowing the fan to keep generating airflow.
- Indoor air quality will be highest as continuous airflow will keep passing airborne pollutants into the air filter.
- A smaller amount of start-stop cycles for the HVAC fan helps lengthen its life span. Since the air handler is often part of the furnace, this means you can prevent the need for furnace repair.
Drawbacks to using the Fan/On setting:
- A continuous fan will likely raise your energy costs 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
Through the summer, warm air can linger in unfinished spaces like the attic or an attached garage. If you keep the fan running, your HVAC system may pull this warm air into the rest of your home, forcing the HVAC system to work more to maintain the preferred temperature. In extreme heat, this may lead to needing AC repair more regularly as wear and tear grows.
The opposite can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually drift into the rest of your home. Keeping the fan on could pull more cold air upward, increasing the amount of heating you need to keep warm.
If you’re still trying to decide 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 could be ideal for you if:
Someone in your household has allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on should help to increase indoor air quality, helping your family breathe easier.
Your home has hot and cold spots. Many 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 minimize these changes by steadily refreshing each room’s airflow.