Author Archives: Brian Bowen

Summer Heat Pushes Power Demand To New Heights

It’s been a cooler than average summer up here in New England, but high temps elsewhere have pushed electric power consumption to record-setting levels. At the end of July, an Arizona heat wave sent electricity demand to a new record high. And on Tuesday, Orlando Utilities Commission set a new record for peak power demand, edging out the previous record set in 2007.

Although both utilities were able to manage the increased demand without a hitch, this is one record—like the record for biggest box office bomb—that no one wants to hold. (That dubious distinction is currently held by 47 Ronin, with a loss of ~$150 million. Ouch!)

So why isn’t a new peak great news? Just like a Hollywood flop, it can be costly. When power consumption rises to record high levels, utilities need to allocate new resources to meet the demand. Usually, that means increased expenses for consumers in the form of building new power plants or increasing new power purchases.

Fortunately, utilities are getting smarter about the way they manage demand for electricity. Through so-called “demand response” programs, they’re giving consumers incentives to use a little less power, which helps keep costs down. Sometimes information itself is enough of an incentive. For example, Orlando Utilities Commission is recommending that homeowners set their thermostat at 78 degrees or higher, about the same temperature of a typical Florida summer morning. By putting out these alerts, utilities are keeping customers comfortable—and avoiding blackouts.

With proper information and planning, utilities have shown they can manage peak demand without breaking a sweat. Or, as Ted Geisler, Arizona Public Service director of power operations, described it during the July heat wave, “We’ve been planning all year for a day just like today.”

Image credit: Chuck Coker/Flickr. CC license.

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Before Air Conditioning, Nobody Worked During The Summer

OK, so that headline’s a bit of an exaggeration. But there’s no question that air conditioning fundamentally changed the way we live and work. According to Stan Cox, especially the way we work.

Cox’s book, Losing Our Cool, was recently written up in the Washington Post‘s Wonkblog, in an article called “How air conditioning transformed the U.S. economy.” If this excerpt is to be believed, it’s really pretty amazing.

Before air-conditioning, American life followed seasonal cycles determined by weather. Workers’ productivity declined in direct proportion to the heat and humidity outside — and on the hottest days employees left work early and businesses shut their doors. Stores and theaters also closed down, unable to comfortably accommodate large groups of people in stifling interiors. Cities emptied in summers…. Houses and office buildings were designed to enhance natural cooling, and people spent summer days and evenings on porches or fire escapes.

Air conditioning has helped us survive the sweltering summers, so it’s no wonder A/C installations are taking off like a rocket in the U.S. The number of U.S. homes with central A/C grew 25 percent from 2001 through 2009. And with more of us working at home, A/C helps us set the right temperature for productivity even when we’re outside the office.

The trick is to stay comfortable, while only cooling the space we use. That way, we can save some of the money we’re spending on energy and put it toward other, cooler uses. Like a bowler hat and monocle. Or at least a decent front porch.

Image credit: simpleinsomnia/Flickr. CC license.

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Should I Run My Air Conditioning All Summer Long?

Lots of homeowners worry about running their air conditioner too long. They want to save energy, or they don’t want to cool rooms that don’t need it. So they only turn on the A/C when it’s really warm out.

That seems like common sense, but there are actually different schools of thought on this issue. In fact, some people worry about running the A/C too little. Why’s that?

For one, when your house is very warm, it takes a lot of energy for your air conditioner to cool it down. The surfaces of your home all store heat—from your roof, to your walls, to your windows. And the greater the temperature differential between indoors and outdoors, the longer the air conditioner has to run to reach the target temperature. So it’s reasonable to think that if you leave the A/C running at a consistent temperature, your system won’t have to work as hard to keep you cool.

That may be true in the short term, but it can create unexpected consequences in the long term.

One big issue is “short cycling.” If your home is always close to your target temperature, your A/C only needs to run for a few minutes to cool it to the proper level. That shorter cycle may be long enough to reach your target temperature, but it’s often not long enough to dehumidify the air. Too much humidity can make your home feel warmer than it actually is, so you may end up running to the thermostat to turn it down even lower.

Also, short cycling isn’t the most efficient way to run your air conditioner. Think of the impact on your gas milage when you drive your car in stop-and-go traffic versus cruising along on the highway. For maximum efficiency, you want your A/C to cruise, not crawl. It can also be noisy. Many homeowners find it irritating it is to hear their system constantly turning on and off.

So, should you run your A/C at the same temperature, all summer long?

We recommend the “cruise control” option. Run your A/C when you need it, and let your programmable thermostat handle it when you don’t. Ultimately, you will save energy—and money—by running your system fewer hours per year.

Image credit: Jeremy Levine/Flickr. CC license.

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