Current mood: chill
It's finally starting to get really hot during the daytime here in the 'Burgh. I've visited a couple of friends and neighbors in recent days, and their A/C runs constantly. I'm close enough to a couple of them to know it runs 24/7, since either I can hear the heat pump kick in, and/or the lights in my own house dim.
My A/C is off. Except on a couple of special, rare occasions, it hasn't been on yet. Chances are good it won't be turned on, even on the hottest days. And why is that? Because I know how to avoid using it.
First thing, my house is very well insulated. This was a winter driven decision. The old furnace used to come on every 10 minutes when we first moved here. After adding a pile of insulation to the attic floor, and blowing the chewed-up newspaper stuff into the exterior walls, I brought my monthly heating bill down from $220/month to $150/month, all at once. My break-even point was about two months.
Second, I have chosen to leave standing two immense shade trees upwind of the house. I realize that with one huge storm, my house will be wearing one of two 70-foot-tall trees, but I'll take my chances. The house is in shade from 11 a.m. to sunset.
Third, and this is both the most important idea as well as the one most easily put to use by anyone, is knowing when to open and shut doors and windows. Simply put, I open doors and windows to get the house cool at night, then keep it cool in the daytime by keeping them shut. This keeps the inside temp in the sub-80° range all day without A/C.
Here are some of the mechanics: After sunset, when the outside temp here starts to drop below the inside temp, I open several windows and doors, and with the help of several box fans (three to five), blow the air out the windows. From experience, I've learned not to blow the fan inward, because the strength of the fan pulls too many little bugs through the screen. Ack. In contrast, the draw of the air through the door screens, while strong, does not pull bugs with it.
Sometimes I leave them going all night, sometimes not. The most effective hours are those just before sunrise, when the outside temperature has typically dropped well below 70°.
By the end of breakfast, the outside temp has risen enough that it no longer makes sense to try to replace warmer air with cooler, so I shut the windows and keep them shut, all day. I may keep one or two of those box fans on low, pointed sideways in the room, to move air around so it doesn't feel stuffy, but the house is and remains cool until well into the afternoon.
How much energy does this save? Plenty. I know from the electric bills that the household does not use 1,000 kilowatt-hours of juice in any summer month, going back to when we first had the A/C in 2003. Using the A/C liberally, as do some neighbors and friends, would essentially double that, at least.
Those fans might draw 100 watts (a one-cent-an-hour pace), but the A/C draws more like 3,000 watts (30 cents an hour). So, do the math. YMMV, of course, but it's sure a lot cheaper to open and shut windows, and a lot easier on the environment, too.