Once the weather begins to cool off, you are probably thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC bills routinely add up to a large chunk of your monthly electric bill. To learn new ways to lower their HVAC bill, some owners look closer at their thermostat. Maybe there’s a setting they could use to boost efficiency?
Most thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a typical cycle, what will the fan setting offer for an HVAC system? This guide should help. We’ll review just what the fan setting is and how 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. Some furnaces can generate heat at a low level in this setting, but in most cases heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will turn on the fan through a heating or cooling cycle and switch it off after the cycle is over.
There are advantages and disadvantages to switching on the fan setting on your thermostat, and whether you do or don’t will depend on your unique comfort needs.
Advantages to trying 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 should improve as steady airflow will keep moving airborne pollutants through the air filter.
- A smaller amount of start-stop cycles for the system's fan helps expand its life span. As the air handler is usually a component of the furnace, this means you might prevent the need for furnace repair.
Disadvantages to switching to the Fan/On setting:
- A constant fan will likely raise your energy bills somewhat.
- Constant airflow could 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
In the summer, warm air will sometimes linger in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system may draw this warm air into the rest of your home, pushing the HVAC system to run longer to preserve the preferred temperature. In severe heat, this can result in needing AC repair more often as wear and tear gets worse.
The opposite can happen during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift into the rest of your home. Leaving the fan setting on may 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 try the fan/on setting, don’t forget that every home and family’s comfort needs are not the same. 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 stressful 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 wrestle with persistent hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting might help limit these changes by constantly refreshing each room’s ventilation.