Solved: Should My Thermostat Be on Fan or Auto?

As the weather starts to cool off, you are probably wondering about how you’ll make the most of your heating and cooling. After all, HVAC expenses can contribute a significant piece of your monthly electric bill. To learn new ways to lower their HVAC bill, some homeowners look closer at their thermostat. Maybe there’s a setting they could use to increase efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is going during a typical cycle, what can the fan setting provide for an HVAC system? This guide will help. We’ll share just what the fan setting is and when you can use it to save money during the summer or winter.

Should I Use My Thermostat’s Fan Setting?

For the majority of thermostats, the fan setting indicates that the system’s blower fan remains on. A few furnaces will operate at a low level in this setting, but in general heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan over a heating or cooling cycle and shut it off after the cycle is finished.

There are pros and cons to using the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your distinct comfort requirements.

Advantages to switching to the Fan/On setting:

• You can keep the temperature in each room more uniform by permitting the fan to keep running.
• Indoor air quality can increase because continuous airflow will keep forcing airborne contaminants into the air filter.
• A smaller amount of start-stop cycles for the system’s fan helps expand its life span. Because the air handler is typically connected to the furnace, this means you might minimize the risk of needing furnace repair.

Drawbacks to switching to the Fan/On setting:

• A constant fan will likely add to your energy bills by a small margin.
• Nonstop airflow may clog your air filter in a shorter amount of time, increasing the frequency you should replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

In the summer, warm air may linger in unfinished spaces like the attic or an attached garage. If you leave the fan on, your HVAC system can gradually move this warm air into the rest of your home, pushing the HVAC system to work harder to preserve the preferred temperature. In serious heat, this may result in needing AC repair more regularly as wear and tear increases.

The reverse can take place over the winter. Cooler spaces such as a basement will hold onto cooler air, which will eventually flow 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 figure out if you should use 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 work for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on is more likely to enhance indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Many homes wrestle with difficult hot and cold spots that quickly return to a temperature different from the rest of the house. The fan setting should help limit these changes by consistently refreshing each room’s supply of air.