If you live in the United States, it's a good bet that your weekend was hot, hot, hot! Mine certainly was. It was 90 degrees here on Saturday and 93 yesterday. Needless to say, we spent a lot of time indoors between the hours of noon and 6 pm. ;-)
But I did learn one very valuable lesson this weekend related to saving on cooling costs. Here it is:
Keep your curtains closed on hot days. It keeps the heat out and the cool (from the air conditioner) in.
This is an on-going issue for my wife and me. I have reminded her for the past year or so, almost on a daily basis, to close the curtains when daylight ends (in the winter) and to not open them on very warm days (in the summer). She responds with 1) "I forget to close them" (in the winter) and 2) "I don't like living in a cave" (in the summer). But this weekend, we saw what a difference this practice can make.
On Saturday, my wife opened the curtains (as usual) when we all had breakfast at 8 am. Despite the fact that we were all out of the house from 9:30 am until noon -- and hence no one would have been made to suffer cave-like problems during that time -- we left the curtains open. The result: the house heated up very quickly and the air conditioner spent most of the day running. Even then, it was hot inside. (And I cringe at what the electric bill was.)
On Sunday, fresh off another "why do we leave the curtains open?" and "because I don't like to live in a cave" discussion, we decided to leave the curtains closed and see what happened. When we got home from church, the house was still cool (71 degrees). And it stayed cool most of the day. In fact, the air conditioner didn't kick on until 3 pm -- despite the fact that yesterday was warmer than Saturday! Better yet, there was still enough light from blinds getting in (not to mention our skylights), that we were certainly far from "living in a cave." It worked out much, much better than I could have imagined. I'm sure we saved tons of money. Even my wife was impressed.
One last thing to note: these weren't even our major sun-bearing windows. The windows/curtains I'm discussing are northern and northeastern windows (we always keep our southern blinds closed -- otherwise we'd be on a constant broil). Yep, all that difference in cooling from closing curtains on windows that really don't let that much sun in -- or so it seems. In fact, it seems like they only let in light, not sun (and heat).
But the fact is that by closing your curtains, you have a great layer of insulation. The light/heat can not get in as easy and the cool air inside can't escape as easily. It's a double win for those of us trying to keep our heating costs below a small fortune in a very warm America.
If you'd like some more tips on saving while cooling, be sure to check out my posts titled Save Hundreds on Your Cooling Bill This Summer, Part 1 and Save Hundreds on Your Cooling Bill This Summer, Part 2.