Can You Turn On Your AC When the Windows Are Open

June 20, 2022
Open Window in Detroit, MI

Many people think leaving the windows open while running their AC during summer is a harmless practice allowing them to get some fresh air. However, having your AC on with your windows open is a bad idea that can undo all your HVAC system’s hard work. Below are some reasons why your windows should remain closed when the air conditioning is on:

1. Irregular Cooling

When you leave even one window in your house open, it causes different temperature zones. If the window happens to be close to the thermostat, the room will be tough to cool because hot air will flow in constantly. Your air conditioner is fighting a losing battle to cool air that is continually flowing into your home from the outside. Some rooms will be extremely cold while your system tries to manage the temperature of the heated room with open windows.

2. Unwanted Dust

Leaving windows open allows dust to enter the house. The air conditioner’s filter might not be able to catch all the debris entering the air handler. These contaminants will cling to the fan motor, evaporator coil, ducting, and electrical components.

If there is a significant buildup of dust, it might cause failures and raise your electrical expenses. Particles on the evaporator coil slow the cooling process. Filters that are dirty will restrict airflow in the air handler. This causes the air conditioner to operate longer. The combination of a blocked air filter and a dirty evaporator coil might cause the coil to freeze, potentially frying the compressor.

You can count on the professionals at [ company_name] to quickly identify and fix your AC problem or provide you with sound advice if your unit needs to be replaced.

3. Delayed Cooling

It’s energizing to open your windows and breathe in the sweet, cool air first thing in the morning. However, in the summer, the air will heat up quickly, and your house will begin to get hotter. When you eventually switch on your air conditioner, it will have to work hard to cool your home. An air conditioner that has been overworked may malfunction, wear out, or need to be replaced.

4. Increased Humidity

When you open the windows, you invite humidity into your home. The longer you keep them open, the more moisture will enter your home. Air conditioners not only keep your house cool, but they also keep the air drier. Your air conditioner will have to work double-time to remove humidity from your home if you open the windows.

5. Gaps Around Windows

Even a small gap in the window will reduce the performance of your air conditioner. It creates a vacuum, forcing out the cold air through your window and sucking air from other areas of your house.

6. Incorrect Cycling

Whenever you leave your windows open, your thermostat becomes desensitized to the desired temperature, and the air conditioner fails to turn off when it should. As a result, the unit will continue to operate, increasing your electric bills since it is cycling far more often than it should.

7. Makes Your AC Work Harder

Whenever cool air is escaping the house, your air conditioner will work harder to keep the home cool. This means that your air conditioning will most likely need to run for longer periods, giving it little time to rest. This will put more strain on your HVAC system, potentially causing it to fail prematurely. Using your air conditioner sparingly can result in a longer lifespan and cheaper utility expenses.

How to Cool Your Space and Allow Your AC to Rest Without Opening Windows

To avoid trapping humidity in your home, leaving the windows open for long durations is not recommended. The idea that the air is colder outside is a fallacy since that isn’t always the case. Below are some measures you may take to keep your home at a comfortable temperature without opening the windows.

Close Blinds and Curtains

Close your drapes and blinds whenever you see the sun is out and getting hotter throughout the day. Maintaining a cool house means keeping rooms out of direct sunshine. In hot climates, this may not make a big difference. This technique prevents the inside of the house from being heated by the sun’s rays.

Tint the Windows

Window tinting and curtain drawing go hand in hand. Tinting your windows can go a long way toward assisting you in maintaining moderate temperatures in your house. Light is reflected away from the home by tinted windows.


Heat can enter your home through more than just windows and doors. The entire house can become excessively heated during the day. Heat-absorbing parts of your home include the walls, floors, and roof. Insulation is the most effective technique to address this problem.

You have an almost limitless selection of materials to choose from when insulating your floors, walls, and roof. Insulating your home may be costly. However, insulation is a long-term investment. Insulation works by keeping heat from entering the home while also restricting cool air from leaving. Your air conditioner will turn on fewer times with proper insulation to ensure a comfortable indoor environment.

Can You Open the Windows at Night?

When the temperature outside has cooled down in late summer, many people have made it a customary practice to open their windows at night. Then, they only turn the air conditioning unit on during the day to keep the house cool. Though this method appears logical immediately, it may not always be effective.

You may be allowing in slightly warmer air inside your home when the sun rises in the morning. When you re-start your air conditioner, it must work much harder, costing you much more to restore the desired indoor air temperature.
It’s also possible that you’re allowing humid air inside your home. The moisture will be absorbed by the furniture and carpet, and the air may feel downright sticky, depending on the level of humidity.

Open Windows Alternatives

The HVAC industry has devised an energy-efficient option for consumers who love to keep windows open in the summer. Energy recovery ventilators (ERVs or HRVs) provide regulated ventilation by removing stale indoor air as they bring in fresh air.

Heat exchange technology is used in each ERV or HRV to transfer energy from the exiting air to the incoming air. Though they consume some electricity, it is significantly less than what you’ll spend after leaving windows open to enhance air quality.

Keeping your windows closed is the most effective way to keep your home cool. Cool air will circulate evenly throughout your home, keeping you comfortable throughout the day. It also saves you money since your system doesn’t have to overwork to get the job done. If you need air conditioning service, C & C Heating & Air Conditioning in Macomb County, MI, or the surrounding areas for exemplary services for all your heating and air conditioning service needs.

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