My air conditioner gave out during the hottest week of July a couple of summers ago. The repair tech could not come for three days, and by the second day the inside of my house felt like an oven preheating.

Those three days taught me more about keeping a house cool than the AC ever did. Here is what actually works.

Treat your house like a fortress

The mistake most people make is opening every window at 2 p.m. to “let in a breeze” when the air outside is hotter than the air inside. All you do is let the heat in.

• Close windows and curtains as soon as the outside heats up
• Open everything back up at night when it cools
• Block direct sun with curtains or a sheet on the south and west windows

The goal is to trap the cool night air inside and keep the afternoon sun out. My house stayed ten degrees cooler once I got the timing right.

Fans do not cool rooms, they cool people

This is the one that surprised me. A fan does not lower the temperature of a room. It cools your skin by moving air over it. So running fans in empty rooms is just wasting electricity.

• Put a bowl of ice in front of a fan for a cheap cool breeze
• Run the bathroom exhaust fan to pull hot air out
• Use ceiling fans and set them to spin counterclockwise in summer

And skip the oven. Anything that generates heat inside the house is working against you. Grill outside or make cold dinners until the worst of it passes.