Early this morning, Tom and I moved our clocks forward for Daylight Saving Time (DST).I mention this not only because it’s timely (that's a pun, I guess), but because some have argued that the switch to DST is good for the environment. This could mean that maybe many of us have actually helped the world today, even if we weren’t trying to. So should we congratulate ourselves on a job well done?
Well, maybe not.
The generally accepted purpose of Daylight Saving Time (not Daylight Savings Time, by the way) is to allow us to make better use of longer summer daylight hours in the evening.
And for many years, it was believed that DST reduces energy consumption as well. Daylight Saving Time means that the sun sets one hour later than it otherwise would -- reducing the period between sunset and bedtime by one hour. It has been argued that this means less electricity would be used for lighting late in the day. Indeed, according to a 1975 U.S. Department of Transportation study, the switch to DST reduced the country’s electrical usage by about 1 per cent a day. (The same might also be true in the winter, except that days are so short that more lighting would be needed in the early morning darkness, offsetting any savings in the evening.)
It all sounds good, except that it’s not clear that it’s entirely correct. In fact, a 2005 University of California study on power usage in Indiana concluded that longer evenings lead to an increased amount of energy use. This is thought to be because when people come home from their day at work and it is still warm and sunny out, they are more likely to use air conditioning. And certainly more people have air conditioning now than 30+ years ago -- when the last study was completed.
So much for being green today. I'll just have to do more.
And for many years, it was believed that DST reduces energy consumption as well. Daylight Saving Time means that the sun sets one hour later than it otherwise would -- reducing the period between sunset and bedtime by one hour. It has been argued that this means less electricity would be used for lighting late in the day. Indeed, according to a 1975 U.S. Department of Transportation study, the switch to DST reduced the country’s electrical usage by about 1 per cent a day. (The same might also be true in the winter, except that days are so short that more lighting would be needed in the early morning darkness, offsetting any savings in the evening.)
It all sounds good, except that it’s not clear that it’s entirely correct. In fact, a 2005 University of California study on power usage in Indiana concluded that longer evenings lead to an increased amount of energy use. This is thought to be because when people come home from their day at work and it is still warm and sunny out, they are more likely to use air conditioning. And certainly more people have air conditioning now than 30+ years ago -- when the last study was completed.
So much for being green today. I'll just have to do more.
2 comments:
Plus we are all cranky from losing an hour of sleep. boo hiss to DST!
I read that the switch to DST also increases your chance of having a car accident on the following Monday -- all those groggy, sleep-deprived drivers on the road.
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