Energy adviser: Heat pump water heaters may be option

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Vancouver homeowners Jenica and Dan Baxter like to call the heat pump water heater in their garage “The Terminator.”

“With a computer on top and its larger size, I expect it to start talking to me one of these days,” Jenica Baxter said about the high-tech water heater, which has been in place for about a year at their house. Basically, the Baxters like the device.

“Nobody’s had a cold shower, yet … that’s something that used to happen,” she said. “We kind of forget we have it.”

Heat pump water heaters work in the same fashion as a regular heat pump heats your house, said DuWayne Dunham, an energy counselor for Clark Public Utilities.

“They transfer heat from ambient air through a reverse-refrigerant process to heat water,” Dunham said. “The technology works to hold down electrical power use and related costs.”

The utility is testing units through a demonstration project with the Bonneville Power Administration and the Electric Power Research Institute. BPA estimates heat pump water heaters have an energy-savings potential of 50 percent or more. The Baxters received a test unit last year.

Heating water for bathing and washing clothes is a major home energy cost, representing about 17 percent of a total power bill for the average three-bedroom, two-bath Clark County home. There are certain drawbacks to heat pump water heaters that customers should understand, Dunham said.

“Most importantly it is not advisable to install the units in an indoor air-conditioned space,” he said. “We think they are best suited for garage installations at this time.”

That’s because the heat pump device robs heat from the room where it is located, which can increase heating costs in winter, especially if you heat with electricity.

The units do best when installed in “semi-conditioned” space, such as a basement or garage, although they should not be installed in a space where the temperature can drop below about 40 degrees.

Heat pump water heaters have been popular in warm climates such as Hawaii and the southern U.S. because they cool the air around them, year-round. The jury is still out in the Pacific Northwest.

Because the Baxters also installed a ductless heat pump and other energy-saving devices a year ago, it has been difficult for them to say how much the heat pump water heater has saved on their energy bill. “We haven’t seen a dramatic improvement but our power bill is definitely lower,” Jenica said.

What to buy

Homeowners can purchase a stand-alone heat pump water heating system as an integrated unit with a built-in water storage tank and back-up resistance heating elements. They can also retrofit a heat pump to work with an existing conventional storage water heater.

Heat pump water heaters require installation in locations with moderate temperatures and at least 1,000 cubic feet of air space around them for air exchange.

Before buying one of these systems, you need to consider the following factors: fuel type, climate, local building code requirements, installation location and safety issues. It is best to have a qualified plumbing and heating contractor install it. Check with Clark Public Utilities for recommendations.

Heat pump water heaters range in price from just under $1,000 to more than $2,000, depending on the size and brand.

A super-efficient traditional electric water heater runs around $900.

Energy Star-qualified heat pump water heaters are eligible in 2011 for a $300 federal tax credit. Be sure to check which models qualify before making your purchase. Clark Public Utilities’ energy counselors can help there, too.

“As we test the technology here in Clark County we’re finding that heat pump water heaters perform well in our mild Pacific Northwest climate,” Dunham said. “For customers looking to maximize energy efficiencies in their homes, these units are a nice alternative to the Energy Star traditional models. The customers who have the units now are very pleased with the performance.”

Energy Adviser is written by Clark Public Utilities. Send questions to energyadviser@clarkpud.com or to Energy Adviser, c/o Clark Public Utilities, P.O. Box 8900, Vancouver, WA 98668.