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Super air conditioners: big chill on energy waste

By Staff writer of The Christian Science Monitor / June 24, 2004



Each summer as 120-degree heat shimmers silver waves across the Mojave Desert, residents of this inferno crank the thermostat down. Air-conditioner compressors and fan motors often run 24-hours a day and for weeks on end.

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The problem is that many air conditioners in this torrid zone are huge power hogs. Which puts Steve Bouman in an unusual position. As head of energy efficiency programs for Mohave Electric, a small power cooperative based in Bullhead City, Ariz., he's got a front-row seat to one of the biggest campaigns for energy efficiency the nation has undertaken in years: high-efficiency air conditioning.

With the new plan, the United States should be able to keep cool while keeping energy consumption under control. Without it, the nation by 2020 would have to build more than 80 new power plants, creating about as much carbon annually as 3 million cars, according to one estimate. And it comes from a Republican administration, following a court battle in which it sought weaker standards.

So, without much fanfare, the US Department of Energy in April announced that all central home units (which use the lion's share of power, compared to just 12 percent for window units) sold in the US must achieve a "seasonal energy efficiency ratio" of 13 starting in January 2006. That's 30 percent more efficient than today's minimum standard of 10 SEER. (The SEER rating is calculated by dividing the total amount of heat removed from the air by the total energy required by the unit.)

Though the standard hasn't kicked in yet, manufacturers are racing to revamp production lines now and consumers are beginning to make the switch, starting with hot places like Bullhead City.

"We're not only in the desert, but the hottest part of the desert," says Mr. Bouman. "We're about 10 degrees hotter than Phoenix. Still, we have a lot of old-timers here who don't have AC. It's 110 to 115 degrees in their homes, but they're used to it."

Newcomers, on the other hand, aren't - and they're becoming more numerous. The region is in the midst of a building boom, fueled by Californians cashing in their pricey real estate to come to the high desert and build one, maybe even two, new homes - renting one out and living in the other. The boom puts Mohave Electric and its 34,000 customers in a quandary. More air conditioners mean more electricity sales but would require buying more costly "peaking power" or, worse, building an expensive new power plant.

That's why Bouman is on the road a lot these days, offering rebates to builders who will install high-efficiency air conditioning - and get others to retrofit homes with high-efficiency air conditioners or heat pumps. Still, energy efficiency can be a tough sell, since many homeowners flee to cooler climes in summer and so are unwilling to invest the hundreds extra to buy a super-efficient air conditioner.

Air conditioning uses only about 15.4 percent of all electricity delivered to homes annually, according to the Energy Information Administration, an arm of the DOE. But air conditioners use all of it in just a few weeks or months - and peak power loads can overstretch generating capacity and overheated power lines, causing blackouts like the one that knocked out power to millions across the eastern United States and Canada last August.

Indeed, air conditioning has a critical impact on peak power demand nationwide - as demonstrated in California, where residential and commercial air conditioning can account for up to 30 percent of the total power load during peaks, according to a Lawrence Berkeley National Laboratory study last year.

That's why energy forecasters keep a wary eye on air-conditioning growth. More than 60 million US homes - about 56 percent of the total - had central air conditioning in 2001, according to an analysis of most recent census data by the Air Conditioning and Refrigeration Institute, representing air-conditioning manufacturers. And that total has grown by some 5 million homes a year over the past decade - up from 39.3 million homes and a 42.2 percent share of all homes in 1991. Nearly 90 percent of new homes built in 2001 had central air.

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