Once the weather is cooling off, you may be thinking about how you’ll make the most of your heating and cooling. After all, HVAC expenses can contribute a large portion of your monthly electric bill. To try and find ways to save, some owners look closely at their thermostat. Could there be a setting they can use to increase efficiency?
The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is on during a regular cycle, what does the fan setting provide for an HVAC system? This guide can help. We’ll walk through precisely what the fan setting is and whether you can use it to cut costs during the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting indicates that the HVAC blower fan keeps running. Certain furnaces can run at a low level with this setting, but for the most part heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will turn on the fan through a heating or cooling cycle and turn it off once the cycle is over.
There are benefits and drawbacks to trying the fan setting on your thermostat, and whether you do or don’t should depend on your unique comfort requirements.
Advantages to trying the Fan/On setting:
- You can keep the temperature throughout your home more uniform by permitting the fan to keep running.
- Indoor air quality can increase since steady airflow will keep moving airborne particles into the air filter.
- A smaller number of start-stop cycles for the system's fan helps expand its life span. Since the air handler is typically connected to the furnace, this means you might avoid needing furnace repair.
Disadvantages to utilizing the Fan/On setting:
- A continuous fan could increase your energy bills slightly.
- Constant airflow could clog your air filter soon, increasing the frequency you’ll need to replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
During the summer, warm air will sometimes linger in unfinished spaces such as the attic or an attached garage. If you use the fan setting, your HVAC system may draw this warm air into the rest of your home, forcing the HVAC system to work more to keep up with the desired temperature. In severe heat, this can result in needing AC repair more quickly as wear and tear gets worse.
The opposite can take place over the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually drift into the rest of your home. Keeping the fan on could pump 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 different. Leaving the HVAC system’s fan on may work for you if:
Someone in your household deals with allergies. Allergies and similar respiratory conditions can be tough 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. Many homes deal with difficult 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 constantly refreshing each room’s airflow.