‘On’ or ‘Auto’: Which Is the Best Setting for Your HVAC Fan?

Finger pressing button on thermostat.

Your air conditioning system will probably be seeing more action as the season progresses. Whether you’re aiming to keep it cool inside your home or save as much as you can on utility bills, it’s important to take note of your HVAC fan setting as well.

Your fan setting can have an impact on your comfort, indoor air quality and energy efficiency, so it’s critical to choose wisely. Most systems have two fan settings: ‘an’ and ‘auto’. Learn more about the difference between these settings as air conditioner repair expert Dependable Heating & Air Conditioning shares a quick comparison below.

Setting the Thermostat Fan to ‘Auto’

The ‘auto’ setting is usually considered to be the most energy-efficient option because the fan only runs when the system is on. This setting provides better dehumidification during the summertime. When the fan is set to ‘auto’, moisture from the cold cooling coils can drip and drain outside. However, when the fan runs continuously, moisture isn't able to drip outside — which causes it to be blown back into your home, after which your air conditioner has to work harder to get rid of the extra moisture in the air.

One disadvantage of the ‘auto’ setting is that hot and cool air aren’t distributed as evenly throughout your home. This happens because the fan stops moving air when the air temperature finally reaches the one set on your thermostat. The blower motor fan may also wear out faster due to more frequent stops and starts, so make sure to check this when doing air conditioning maintenance.

Setting the Thermostat Fan to ‘On’

Letting the fan run uninterrupted enables the system to provide an even distribution of warm or cool air in your home. This also reduces stress on the fan, which is typically makes frequent stops and starts.

However, setting your thermostat to ‘on’ will likely cost you more money, especially when your fan runs nonstop. It might be best to check your HVAC system and see whether or not the blower motors can handle being on continuously. Take note that some blower motors aren’t designed for continuous use.

Whether you need to install a new air conditioner or repair the old one, Dependable Heating & Air Conditioning can help. We’ve been in business for over 50 years, and local customers have come to trust us for our quality service. Call us at (707) 247-2887 or fill out our contact form to schedule an appointment.

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