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Should my HVAC Fan be Turned to On or Auto?

If you’ve looked at your thermostat, you’ve probably noticed two options for your fan: On or Auto. Unfortunately, it can be a little confusing to know which setting is the most efficient and best for your system.

Luckily for you, Rainaldi Home Services has listed the pros and cons of each option.

But, first, let’s explain the fan’s role in your air conditioning unit. The cold air from your air conditioner is forced through your ductwork by a blower motor inside the outdoor unit. This blower is the “fan” and is controlled by the fan setting on your thermostat.

Auto – This means the fan will turn on only when your system is running. So, once your thermostat has reached the set temperature, the entire system will shut down. This includes the blower fan.

  • Leaving your system’s fan set to “auto” is the most energy-efficient option out of the two because energy is only used when the entire system is running.
  • The auto setting allows for better dehumidification because the moisture from the coils can drip and be drained outside when the fan turns off.
  • One con to the auto setting is that you may notice a less even distribution of hot or cool air because the fan stops pushing air through once the thermostat has reached optimum temperature. Some rooms may stay warmer/colder than others because not all the air has reached them.
  • A second disadvantage is that you might find that the motor to the blower fan wears out faster, thanks to the starting and stopping.

On – This means the fan will continually run, even when your system isn’t working to heat or cool the air.

  • Leaving the fan to run continuously will help distribute the cooled (or heated) air throughout your home since the fan continues to run after the system stops cooling. This does help even out the distribution.
  • Also, because the fan isn’t constantly starting and stopping, there is less wear and tear on the motor in terms of that start/stop motion.
  • However, leaving your blower motor set to “on” means the fan is always running. This means an increase in the use of electricity, which equates to higher energy costs.
  • Maybe not quite as obvious is that leaving your fan set to “on” will increase the humidity in your home. You want to escape that Central Florida humidity when you walk through the door, don’t you? If the fan is constantly running, then your air conditioning unit can’t dehumidify your home as well as it should.

As with any decision about your home’s comfort, you can choose which is best for your budget, family, and home. The experts at Rainaldi Home Services have been serving the Orlando area since 1974, and we’ve seen the good and bad sides of blower fan settings. Give Rainaldi a call ((407) 413-9795) to schedule an appointment and let us help you make the right decision for your home and your family’s comfort.

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