"Texas cool" is a morning and evening routine that takes advantage of cool outdoor temperatures at night and keeps the heat at bay as much as possible during daylight hours. It's very simple to do: At night when the temperature drops, open windows and bring in cool air with window fans or a whole-house fan. As soon as the sun comes up or the air starts to heat up, shut the windows and shades and keep doors closed.
Cost: $0 (plus minimal fan use)
Benefit: 20 to 50 percent off your cooling bill