Set your thermostat two degrees lower and your cooling bill jumps by about six percent. Do that all summer and you are throwing away money just to feel a draft. I stopped cranking the AC years ago and my house stays comfortable with the unit barely running.

It comes down to stopping heat before it gets in and moving air once it does.

Block the sun during the day

Windows are the biggest heat entry point, especially ones facing south and west. Close the curtains or blinds on the sunny side before noon. Blackout curtains work best, but even cheap white sheets draped over the rod help. In my house, closing the west-facing blinds cuts the afternoon temperature swing by four degrees.

Use fans the smart way

A fan does not cool the air, it cools you by moving air across your skin. So run fans where you are, not in empty rooms. At night, put a fan in the window blowing inward on the cool side of the house and another blowing outward on the far side. That cross breeze pulls the hot air out and drags cool night air in.

Cook outside or late

The oven is a radiator wearing a disguise. Use the grill, the microwave, or a slow cooker instead, and cook later in the evening when the house is already cooling down. I moved my pasta cooking to the mornings on hot weeks, and the kitchen stopped feeling like a sauna by dinner.

Turn off things that make heat

Computers, game consoles, and even big TV screens pump out heat. Turn them off when you are not using them. One summer I found my gaming PC was running idle all day and heating up my whole office. A power strip with a switch fixed that in a second.

Let the house cool at night

When the sun goes down and the temperature drops below the indoor temp, open the windows and let the cool air in. Run fans to push it through. Then close everything up tight first thing in the morning to trap the cool air inside. This is the whole secret: cool at night, seal in the morning.

Do all of this and you can keep the AC at a reasonable setting, or off entirely on mild days. My power bill dropped about twenty percent the summer I started blocking the sun and opening up at night.