Spring is a beautiful time in South Florida, and after the long winter (for us, anyway), it’s great to be able to open windows and let the breeze blow through the house. But in the past week, summer has started to sneak in. If you haven’t turned on your air conditioning yet, you know you will soon.
I gave in one afternoon, but after it rained that night, I was able to turn off the air conditioning and open the windows again. Which brings us to a question I’ve never been able to answer: When does it become less expensive to run the air conditioning all day than to turn it on for a few hours?
I put this question to the experts at Florida Power & Light, who did some research and came back with this answer: It depends. Humidity, the dew point, the outside temperature, the construction of your house, the efficiency of your air conditioning system — all these factors come into play.
FPL did remind me that the longer the system runs, the more it costs. And, for every 2 degrees you raise the thermostat, you save 9 percent on cooling costs. Turning off the system for hours at a time might save money — if you don’t have to run it longer than you would normally to cool down the house.
The FPL experts turned up one experiment done in Cocoa in 1985 that found opening windows at night during the summer increased 24-hour air conditioning use by about 30 percent if the average daily temperature was 82 degrees. If the average was 77 degrees, it was a wash cost-wise.
After mulling over the scientific evidence, such as it is, I’ve decided to keep doing what I’ve always done. Any time I can turn off the air conditioning and open the windows for a few hours, I’m going to do it. If it costs me an extra $10, it’s worth it to feel the breeze and hear the birds.
