Sleeping with the windows open & turning off your a/c unit seems like a great way to save energy.
It makes sense to provide your HVAC a break when the sun sets & the temperature drops, does not it? Unfortunately, that is not always the case.
One of the ways you might be unknowingly driving up your utility bill is by sleeping with the windows open at night. Your a/c unit has worked strenuous to cool your home, however if you leave your windows open all night, it has essentially undone all its strenuous work. The AC system detachs heat & humidity from the indoor air during the day. The system will have to toil harder to restore your desired temperature if the outside air temperature is even 1 degree warmer than the inside air temperature. Additionally, the outside air contains more humidity than the inside air, making your rooms assume stuffy & uncomfortable. The presence of humidity makes hot & cold temperatures appear warmer than they truly are. In the event that your home becomes too damp, you might assume inclined to set your control unit even lower to compensate. Sleeping with open windows has been shown to be beneficial in some studies. You can crack a window overnight if the outside temperature is about 69 degrees & the humidity is low. You should, but, close them as early in the afternoon as possible to prevent outside moisture & sunshine from changing your internal temperature.