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This One Thermostat Setting is Making You Sweaty

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Summer’s here. And you’re probably staying indoors more to escape the heat and humidity that comes with Minnesota summers.

But have you found that you’re still feeling warm and sweaty inside, even when the air conditioner is running?

Yes, this could be a sign that you need a new air conditioner. But it could also be fixed by simply changing the setting of your thermostat.

If you’re leaving your AC fan set to ON, your home’s humidity levels are probably too high for comfort.

Not seeing the correlation between a fan setting and humidity? We’ll explain.

How leaving your fan set to ON affects your humidity levels

First, let’s go over how your indoor unit works.

  • Step 1: Warm air is pulled into the unit from inside your home.
  • Step 2: The air hits the fan and is pushed up towards the refrigerant coils.
  • Step 3: The warm air is blown over cold refrigerant coils. The coils absorb warmth and moisture from the air.
  • Step 4: The air (now dry and cool) is pushed back into your home.

Now let’s focus on step 3: When warm air hits the refrigerant coils, water and heat is pulled from the air. As a result, moisture is left behind on the refrigerant coils.

And depending on your fan setting, two things can happen with that moisture:

If your fan is set to AUTO, that moisture is removed from your home.

When your fan is set to AUTO, it stops running between cooling cycles. And when the fan isn’t blowing, the moisture sitting on the refrigerant coils collects and drains outdoors. This process dehumidifies your home, leaving you with cool, drier air.

If your fan is set to ON, that moisture is blown back into your home.

When set to ON, your fan runs constantly. The moving air causes the condensation to evaporate back into your home’s air rather than dripping into your condensate drain. 

So why is indoor humidity bad?

First off, some humidity is good. Not enough moisture in the air causes dry skin and irritates the eyes, nose and throat.

The Environmental Protection Agency suggests keeping the level of indoor humidity at 30-50%.

When humidity levels exceed 50%, it can cause:

  • Discomfort—Humidity makes it harder for our sweat to evaporate, making us feel warm and sticky.
  • Sickness—Bacteria and other microscopic organisms thrive where there is moisture and pose a threat to your health, especially if you have allergies or asthma.
  • Damage to your home—Moisture promotes the growth of certain wood-eating fungi that can damage your home.
  • Dust mite and cockroach infestation—Dust mites and cockroaches nest in humid, moist conditions.
  • Mold—Homes that have at least 60% humidity are the perfect breeding grounds for most species of mold.

If you need professional help controlling your indoor humidity, contact us at MSP. 

We can inspect your unit and perform any maintenance needed to keep your family cool and dry throughout the summer!

Minneapolis-St. Paul Plumbing, Heating and Air has served the Twin Cities since 1918.

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Categories: Air Conditioning