VTDigger: SOLAR HEAT PUMPS SEEN AS ANOTHER TOOL IN ENERGY EFFICIENCY KIT
by John Herrick, September 12, 2014
Betsy Hardy of Richmond owns a two-story home built more than a century ago. Over the past three years, she has insulated her attic and basement, installed a solar array on her roof and placed a solar hot water heater in her basement.
Now, she is working with an electrician to install two heat pumps as her primary heating source this winter.
“I really want to reduce my carbon footprint,” Hardy said. And, she said, “I think it’s a good investment because it will make my home a lot more affordable for me after I retire if I don’t have to spend lots of money on fuel oil.”
Heat pumps have been available in the U.S. for decades, but it was not until recently that the technology could be used to heat homes in Vermont, where temperatures frequently dip below freezing.
Like a refrigerator or air conditioner in reverse, electric air source heat pumps use a refrigerant to extract heat from the cold outside air and pump it inside. Even in sub-zero temperatures, there is heat in the air. But as the temperature drops, the technology must work harder to extract the heat from the air. Eventually, the system becomes less efficient and stops producing heat.
Hardy is a member of the Richmond Climate Action Committee, a town energy group that provides residents information about energy efficiency and renewables. As she prepares to test the technology herself, renewable energy advocates and businesses are pushing to put heat pumps into homes before winter hits.
Proponents of the technology say heat pumps can warm homes in temperatures as low as minus-18 degrees Fahrenheit, generating average savings similar to natural gas compared to heating fuels like oil or propane.
Hardy said she is installing a large heat pump on her first floor and a smaller one in a second-floor bedroom. This year, she said she will keep her oil furnace as a back-up for colder days, but will consider replacing it with a wood stove if the heat pumps work well enough.
She said she will capitalize on the net-metering energy credits her utility gives her for the solar power her panels produce in the summer. In the winter, she will use the credits to power the heat pumps, effectively heating her home with energy from the sun year-round.
SunCommon, a Waterbury-based solar installer and financier, announced this week it is partnering with heat pump installers to offer solar-powered heat pumps with no upfront costs across their service area.
Taylor Ralph, a solar organizer with SunCommon, said heat pumps are the most efficient way to heat a home. On an annual average, the Department of Public Service estimates air source cold climate heat pumps provide 2.4 times more heat energy than the electric energy used to power the unit.
There are no state incentives for heat pumps in Vermont. The state’s efficiency utility,Efficiency Vermont, will seek permission from state regulators to use electric customers’ money to offer rebates for heat pumps, as the utility does for other energy efficiency projects.
Lawmakers approved the plan last session, but asked the utility to make sure homes are sealed up first and that the heat pumps will not impact electricity prices by increasing demand.
Nonetheless, Ralph said homeowners should not wait for heat pump rebates if they want discounts on the solar component of the installation. The state’s 25 cents per watt solar incentive will end Dec. 31. She said homeowners could receive up to $2,500 for systems planned or installed by the end of the year.
Green Mountain Power is renting heat pumps for $52.99 per month for their largest — and most popular — heat pump that produces 18,000 British thermal units, which they say can heat one or two rooms in an average home.
Homeowners can lease the heat pump for 15 years — equaling about $9,500 to have the largest pump installed and maintained annually — after which the homeowner can return the heat pump, purchase it or extend the lease. GMP says the technology can last up to 20 years.
By comparison, heat pumps typically cost from $3,000 to $4,000 per unit and can be paid off in about 3 to 6 years with immediate energy savings, according to Ben Walsh, a clean energy advocate for the Vermont Public Interest Research Group.
Amanda Beraldi, of GMP’s Energy Innovation Center, said the utility has installed 185 units in Rutland and Montpelier, and hopes to install 200 by the end of the year. She said the company plans to expand its pilot program to other communities. She said these systems save customers switching from propane or oil from 25 percent to 50 percent on heating costs.
Homeowners can use heat pumps in different ways. Much like a wood stove, heat pumps can be used to heat one or more rooms at a time. With additional installations, heat pumps can be used as a primary heating source nearly year round, but even installers recommend a backup heating source.
In the summer, heat pumps can also be used to cool homes with less electricity than a traditional air conditioner. Beraldi said heat pumps are three times more efficient than air conditioners.
While heat pumps may work in many homes, some businesses have decided to use natural gas instead, a heating option currently competitively priced with heat pumps.
Douglas DiMento, a spokesman for Agri-Mark, a company that works with about 250 Vermont dairy farmers to make cheese, whey protein and whey permeate for animal feed abroad, said the company uses a tank of No. 6 fuel oil each day to process the dairy products.
DiMento said dryers up to 90-feet tall process the protein powders. By switching to natural gas, he said the company Middlebury facility estimates saving up to $3 million per year.
He said the company looked into all sorts of technologies before deciding to switch to natural gas, including heat pumps. But he said the company’s sustainability team did not find heat pumps to be the best solution for the commercial operation.
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