When the weather is cooling off, you are probably concerned about how you’ll prepare your heating and cooling. After all, HVAC expenses routinely make up a significant portion of your monthly electric bill. To learn new ways to save, some people take a closer look at their thermostat. Could there be a setting they should use to boost efficiency?
Most thermostats have 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 precisely what the fan setting is and when you can use it to save money in the summer or winter.
What Is the Fan Setting on My Thermostat?
For the majority of thermostats, the fan setting means that the HVAC blower fan stays on. Some furnaces will generate heat at a low level with this setting, but in general heating or cooling isn’t being generated. The ‘Auto’ setting, in contrast, will run the fan over a heating or cooling cycle and shut it off when the cycle is finished.
There are pros and cons to trying the fan setting on your thermostat, and whether you do or don’t will depend on your personal comfort needs.
Advantages to trying the Fan/On setting:
- You can keep the temperature in each room more uniform by enabling the fan to keep running.
- Indoor air quality should improve as constant airflow will keep passing airborne pollutants through the air filter.
- A smaller number of start-stop cycles for the system's fan helps lengthen its life span. Since the air handler is often connected to the furnace, this means you can minimize the risk of needing furnace repair.
Disadvantages to utilizing the Fan/On setting:
- A continuous fan will likely add to your energy bills by a small margin.
- Nonstop airflow could clog your air filter in a shorter amount of time, increasing the frequency you will want to replace it.
Should My Thermostat Be on Fan or Auto in Summer/Winter
In the summer, warm air can persist in unfinished spaces including 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, compelling the HVAC system to work more to preserve the desired temperature. In severe heat, this could result in needing AC repair more often as wear and tear increases.
The opposite can happen over the winter. Cooler spaces like a basement will hold onto cooler air, which may 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 remain warm.
If you’re still trying to determine 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 may be ideal for you if:
Someone in your household suffers from allergies. Allergies and other respiratory conditions can be tough on the family. Leaving the fan on should help to improve indoor air quality, helping your family breathe easier.
Your home has hot and cold spots. Lots of homes wrestle with persistent 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 consistently refreshing each room’s airflow.