Water will cool you off even faster than air. Direct contact with cold water not only provides instant relief through evaporative cooling, but also has lingering effects that can help get you through the last couple of hours before sunset. Wear a dampened kerchief around your neck. Take cold showers and drink plenty of water. If your garden needs a drink, set the sprinkler to overshoot a little and send the kids (or yourself) out to cool off.
Mechanical evaporative coolers — units that transfer heat from air to water to create a cool breeze — are highly effective in regions with hot, dry summers. You can also achieve this type of cooling via lower-tech methods, such as hanging a wet sheet over an open window or door to catch the breeze coming through, or situating a fan to blow air across salted ice or frozen water bottles.
Cool nighttime air can often be used to cool a home. This works really well in hot, desert climates, but also humid climates early and late in the cooling season. So, before you turn your thermostat down to cool your home, be sure to check outside temperature. If it’s below 75oF – and it often is early and late in the cooling season in many locations – open windows and let the cool nighttime air cool your home.
To accelerate the cooling, a whole house fan can be switched on. Or, you can place a couple box fans in windows to draw cool air into your home. Fans use a lot less energy than air conditioners.
Opening windows in upper stories also helps draw hot air out of a home, accelerating the influx of cool air from lower windows.
Next morning, shut the windows to prevent daytime heat gain. You may want to draw curtains to reduce heat gain during the day, especially if you are gone during daylight hours at work or at school.