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There’s a misconception that “if one is good, two are better.” If one slice of a 1,000-calorie caramel-fudge-butterscotch cake is good, two must be better. If having one credit card is good, two must be better. If having your air conditioning unit running is good, running it while windows are open must be better. We can’t vouch for the first two, but the last one is definitely not true.

You may think that opening windows while the air conditioner is running will cool the room faster. You may also think that the fresh outdoor air will perk up the cold, motionless indoor air. Unfortunately, leaving the windows open while running your air conditioning can cost you in many ways. Here’s why it’s best to close your windows when your AC is on:

1. Irregular Cooling

When even one window is open, it creates dissimilar temperature zones within your house. If the window is near a thermostat, that room will be impossible to cool, since hot air is constantly flowing in.

It’s kind of like those cartoon characters you may have seen who are in a sinking boat. They’re using buckets and buckets to bail the water out, but it keeps flooding. Your AC is in a similar futile struggle to cool air that’s constantly flowing. While it’s trying to regulate the hot room’s temperature, it’s turning the unaffected rooms into iceboxes.

2. Unwanted Dust

Leaving windows open brings dust into your home. Your air conditioner’s filter may be unable to trap the particles that enter the air handler. These impurities will plaster its evaporator coil, fan motor, ducts, and electronic components.

If this buildup is substantial, it can trigger breakdowns and escalate your electricity bills. Dust on the evaporator coil impedes the cooling process. Dirty filters constrict airflow through the air handler. This drives the AC to run longer. A clogged air filter paired with a dusty evaporator coil may cause the coil to freeze and possibly fry the compressor.

The experts at Progressive Air Systems can effectively diagnose and remedy the problem or give you insightful guidance if your system needs to be replaced.

3. Delayed Cooling

It’s invigorating to throw the windows open in the morning and inhale the sweet, cool breezes. Why leave the air conditioner on? Well, in the summer, air is going to heat up fast, and your house is going to start cooking. When you finally turn on your AC, it will need to strain to get your house nice and cold. An overworked air conditioner can also malfunction, wear out, or need to be replaced.

4. Increased Humidity

Leaving windows open before turning on the air conditioner is an open invitation for humidity. The longer you leave them open, the more that humidity can permeate your home. Along with keeping your house cool, air conditioners keep it free of excess humidity. By the time you close your windows, your AC has to do double-duty to eliminate humidity, and your electricity bill will reflect this.

5. Forcing Cool Air Out

Even opening a window a crack is going to interfere with your air conditioner’s efficiency. This creates vacuum pressure that will force the cool air out of your window and siphon air from other gaps in your home. You can see this happening when your curtains are sucked against the window and flattened out.

6. Incorrect Cycling

When you leave windows open, the thermostat will be desensitized to the right temperature, and the AC won’t shut off when you want it to. This will cause the unit to keep running, ratcheting up your bill because it’s cycling much more frequently than it should.

Use Air Conditioning At Night

In Florida and other hot climates, many homeowners turn off their air conditioners and open their windows at night. This actually makes homes less comfortable than they could be with the AC on and the windows closed. You’ll be inviting a lot of moisture inside that could damage your house.

Research by the Florida Solar Energy Center (FSEC) analyzing several test homes determined that five more gallons of water accumulated in houses that were opened for the night than those that were closed.

In Florida’s heat and humidity, morning temperatures are about 77 degrees to 80 degrees. The air is usually near saturation at 95% or more relative humidity. If you turn your air conditioner off at night, this excess moisture will actually make you feel more uncomfortable. When the air has to crank on during the day, it will exhaust a lot of energy reaching an adequately cool temperature.

Opening your windows when your air conditioner is running may feel refreshing, but it has more shortcomings than benefits. When your windows are open, and your AC is running, the unit can be stressed or damaged. It may even break down completely.

Contact Us

Progressive Air Systems is here to help get your air conditioning up and running. Backed by 33 years of experience, we provide our Tampa Bay area customers with expertise and honest work ethics. Our skilled professionals can analyze and rectify your AC issuesContact us today and we’ll show you that we’re not just window dressing.