Once 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 costs can add up to a big portion of your monthly electric bill. To try and find ways to save, some homeowners look closer at their thermostat. Is there a setting they could use to increase efficiency?
Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a typical cycle, what will the fan setting provide for an HVAC system? This guide will help. We’ll walk through just what the fan setting is and how you can use it to reduce costs in the summer or winter.
What Is the Fan Setting on My Thermostat?
For most thermostats, the fan setting means that the HVAC blower fan remains on. Certain furnaces will operate at a low level with this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, on the other hand, will turn on the fan over a heating or cooling cycle and switch it off after the cycle is over.
There are advantages and disadvantages to using the fan setting on your thermostat, and what's ideal will depend on your personal comfort preferences.
Advantages to using the Fan/On setting:
- You can keep the temperature in every room more balanced by allowing the fan to keep generating airflow.
- Indoor air quality should improve because continuous airflow will keep passing airborne contaminants through the air filter.
- Fewer start-stop cycles for the system's fan helps extend its life span. Since the air handler is usually part of the furnace, this means you might prevent the need for furnace repair.
Drawbacks to utilizing the Fan/On setting:
- A constant fan can raise your energy bills slightly.
- Constant airflow can clog your air filter in a shorter amount of time, 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 will sometimes persist in unfinished spaces such as 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, pushing the HVAC system to work harder to keep up with the set temperature. In extreme heat, this could result in needing AC repair more quickly as wear and tear gets worse.
The reverse can occur in the winter. Cooler spaces such as a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on could pump more cold air upward, increasing the amount of heating you need to remain warm.
If you’re still trying to determine if you should try the fan/on setting, remember that every home and family’s comfort needs are different. Leaving the HVAC system’s fan on could work for you if:
Someone in your household suffers from allergies. Allergies and similar respiratory conditions can be hard on the family. Leaving the fan on is more likely to increase indoor air quality, helping your family breathe easier.
Your home experiences hot and cold spots. Lots of homes wrestle with stubborn hot and cold spots that quickly evolve to a temperature different from the rest of the house. The fan setting should help limit these changes by steadily refreshing each room’s supply of air.