Don’t Set Your Thermostat Like This (Unless You Like Living in A Humid Home)

June 21, 2016

Most of us know how to operate an AC thermostat but are you aware that there are actually two fan settings to pick from: AUTO and ON?

So what does each setting mean and which one should you use for your home?

In this article, we’ll explain the difference between the two fan settings and why leaving your thermostat set to ON makes your home incredibly humid and uncomfortable.

What happens when your thermostat is set to ON

If you leave your thermostat set to ON it means your fan will run continuously, even when your AC is not producing cold air.

There are 2 main problems with letting your fan run non-stop:

  • Your AC fan runs off of electrical energy so leaving it on 24/7 runs up your utility bills
  • It restricts your AC’s ability to dehumidify the air inside your home

Wondering how a running fan contributes to humidity?

Your indoor AC unit produces condensation as it absorbs heat and moisture from the warm air inside your home. When your fan runs constantly, it blows that moisture right back into your house. This means your home stays humid and will never dehumidify to a comfortable level.

What happens when your thermostat is set to AUTO

If you leave your thermostat set to AUTO it means that your fan runs only while your AC is producing cold air. In between cooling cycles, the fan shuts off.

Unlike the ON setting, the AUTO fan setting actually dehumidifies your air. Dehumidification happens when moisture is stripped from the warm air inside your home. Because the fan shuts off between cooling cycles, that moisture has time to collect and drain outdoors.

Over several cooling cycles, this process leaves your air cool and dry.

So should I ever set my AC fan to ON?

There are some instances when using the ON setting works to your advantage:

  • When you’re vacuuming—A vacuum kicks up a large amount of dust in your home. But if your AC fan is running, it helps suck up the dust into your air filters where it gets trapped instead of settling back onto your carpet and furniture.
  • If someone in the house has allergies—If you have a high efficiency HEPA air filter and your fan is running, more air contaminants are trapped. This results in cleaner air.

Have more air conditioning questions? Just contact the professionals at Advanced Air for help or call us at (239) 321-5222.

Advanced Air has been serving Fort Myers and Naples, Florida, and the surrounding areas for over 25 years.

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