Measuring the renovation in cost and in impact

Saturday, January 23, 2010

Otto Condon is a calculating sort of guy -- in a greenish way.

One of his more whimsical standards of measure, $600, is from a few years ago, when the Bureau of Labor Statistics estimated that to be the average monthly cost of owning and operating a car, including fuel, repairs and insurance.

So the carless Condon, who subscribes to the car-sharing service Zipcar, determined that the air-jet BainUltra tub in his renovated bathroom, for instance, would cost him "a couple of months of car ownership." The colored LED lights on the tub were "another month, maybe half a month."

At about $700, the tankless gas-fired water heater he specified for his District rowhouse was a little more than a month's car ownership and twice as much as the cost of a standard water heater with a tank. "The upfront cost was higher, but it costs me a lot less now because I'm not heating the water 24 hours a day," he said. "The coils fire up only when there's demand." (One tankless manufacturer, Rheem, claims its gas-fired tankless water heaters cost 30 percent less to operate than standard gas water heaters and 70 percent less than standard electric water heaters.)

But Condon's most serious calculation was applied to something that cost more than some cars. As part of his whole-house renovation, he paid $22,000 for 12 solar panels, mounted on his roof to generate electricity. Tempering that figure significantly was an $11,000 grant he received from the D.C. Department of the Environment, as well as a federal tax credit of $2,000. (The latter would be somewhat larger today under more recent tax rules.)

The calculation doesn't stop there. In its "Mid-Atlantic Region Consumer's Guide to Buying a Solar Electric System," the U.S. Energy Department points out that solar-generated electricity can cost a resident two to three times what commercially available electricity costs.

The upside? Such energy is produced without noise or pollution and is renewable, though the solar panels themselves have a finite useful life -- 25 to 30 years, according to panel manufacturers, with some tapering of efficiency over time.

On a partially overcast day this week, Condon estimated that his passive solar system generated five kilowatts of energy and his house used three of them.

"My usage is pretty low," he acknowledged. The average American house, he said, generally uses 25 to 35 kilowatts a day. Last year, Condon generated 2,400 kilowatts and consumed 1,700.

As with most standard energy agreements for residences connected to the nation's power grid through the local electric utility, the excess kilowatts Condon produced were granted to Pepco. On the other hand, Condon has a contract with Astrum SRECs, a company that trades his solar renewable energy credits to commercial power providers. "I just got my first [annual] check, for $670," he said.

Condon's monthly Pepco bill: $5 for hookup to the power grid.

-- Nancy McKeon

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