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Should I Set HVAC System Settings to Auto or On?

- 10:28 am - October 21st, 2019

October Image.jpgWondering whether you should set your thermostat blower to “auto” or “on”? Noonan Energy has the answers! Keep reading for MA home comfort wisdom.

How to Properly Set Your Thermostat Control

Thermostats in Massachusetts seem simple enough, but there’s one feature that stands out as a common source of uncertainty: the mysterious blower motor fan, which helps distribute hot and cold air throughout your home until the thermostat’s desired temperature is achieved. Noonan Energy is here to unpack the mystery and give you the MA home comfort answers you’re looking for.

Should You Set Your MA Blower Motor to “On” or “Auto”?

Here’s the thing—there’s no one-size-fits-all answer to this question. There are pros and cons to setting your furnace, boiler, or central air conditioner’s fan to “on,” just as there are benefits and drawbacks to setting it to “auto.” For that reason, we’re going to lay all the information on the table and let you decide which thermostat setting will work better for your family’s Massachusetts home comfort.

Setting Your Blower Fan to “On”

A blower motor in the “on” position will run fans continuously, even after the desired thermostat temperature is reached. Here are some things to know if you leave your blower motor on.


  • Reduced hot or cold spots in your home due to more even air distribution
  • Reduced stress on the fan due to fewer stops and starts, extending its lifespan
  • Indoor air quality could improve if it’s pulled through filtration more frequently


  • It may cost you more to run your fan nonstop. Not every fan is designed for continuous use
  • You may notice cool airflow during the winter, since the fan is on when the heater is not
  • You’ll have to replace your furnace filter more frequently, since more air passes through
  • During summer, hot air in ductwork can be blown into your home, increasing the temperature

Setting Your Blower Fan to “Auto”

An automated blower motor turns off when the thermostat’s desired temperature is reached, and back on whenever it needs to adjust your home’s comfort. Check out the pros and cons of automation.


  • Since the fan only runs when it needs to, auto is the most energy-efficient option
  • You’ll enjoy better dehumidification by allowing the cold cooling coils to drain outside
  • Air is continually being cleaned, giving you healthy indoor air quality


  • It’s possible that you will notice less even distribution of temperature in your home
  • The blower motor fan may wear our faster due to more frequent stops and starts

Get a Free Recommendation from Noonan Energy’s Experts

When you look at the numbers, the “auto” setting’s pros more heavily outweigh the cons when it comes to your thermostat’s blower motor settings. However, if you’d like a free personalized consultation or recommendation, feel free to reach out to our energy experts! They’ll be more than happy to help you.


  • HVAC
  • thermostat
  • boiler
  • furnace
  • central a/c