An open window allows air to circulate in a home and brings in desirable fresh air. However, when it is warm outside and your central air conditioning is turned on, having a window open adversely affects the cooling of your home. Having a window open with central air turned on can cost you in many ways.
Keeping a window open while your central air conditioning unit is running creates different temperature zones throughout the home. On a hot day, if the open window is near a thermostat, this area of the home will remain warm as outdoor heat constantly filters in. Other rooms will become much colder as the system runs in an attempt to cool the hot room.
Keeping a window open while your central air is on forces the unit to run more than it should have to in order to cool your home to the desired temperature. This excessive use of air conditioning is environmentally inefficient because it wastes energy.
Higher Energy Costs
Because the amount of time your air conditioner is operating determines the expense on your energy bill, leaving windows open while the unit is on will cost you money. Broken or leaking windows also raise energy bills, which is why you should seal drafts with caulk or appropriate weather stripping.
Keep Windows Closed
The most efficient way to cool your home with central air is to keep your windows closed. Cool air will evenly distribute across the rooms in your house and keep you comfortable throughout the day. If you want fresh, outdoor air, turn off your system and open the windows at night.