Crack a window
Cooling down the house can be as easy as opening a window. Overnight ventilation is key―before you sleep, open the windows to allow cool air to circulate through the house. During the day, hang a thin, damp sheet in front of the open window to create a cool breeze. But when temperatures hit their peak, from about noon to 2 p.m., make sure all windows are shut tight to keep out the stifling air.