Warmth pumps are helpful for preserving heat in Maine. However they’ll’t substitute a house’s central heating system on the coldest winter days, particularly in an outdated home.

That was what Kathy Heseltine understood to be true, so she was skeptical when a guide working for Effectivity Maine got here final yr to her Freeport cellular dwelling park with a proposal. The company would take out her kerosene-fired furnace and set up a whole-house warmth pump, freed from cost. If she wasn’t blissful after a yr, the guide stated, he’d hook up the outdated furnace once more.

Right this moment, Heseltine is a warmth pump evangelist. The 37-year-old cellular dwelling she lives in along with her husband, Sam, is extra snug within the winter, cooler in the summertime, and cheaper to warmth. She even satisfied a sister to get one.

“This has been an actual revelation,” Heseltine stated. “We actually imagine on this product, and I used to be a tough promote at first.”

The Heseltines are a part of an indication undertaking that swapped central heating methods final yr with warmth pumps in 10 cellular houses. The intention was to point out that right now’s high-efficiency warmth pumps can do the job alone in subzero temperatures – and counter a notion that they aren’t appropriate as stand-alone heating methods.

The undertaking is the primary within the nation to check the impression of retrofitting cellular houses fully with warmth pumps, in line with Effectivity Maine.

In a separate examine, consultants additionally changed current methods in 9 stick-built houses, starting from a century-old condominium on Nice Diamond Island to a more recent single-family dwelling in Sanford.

Taken collectively, the outcomes are supposed to assist validate the efficiency of high-efficiency warmth pumps. They’re a vital factor of Maine’s Local weather Motion Plan, which seeks to get 100,000 new warmth pumps in houses and companies between 2020 and 2025, with an extra 115,000 whole-house methods by 2030.

Greater than 27,000 new warmth pumps have been put in final yr, inspired by Effectivity Maine rebates that vary from as much as $1,200 for residents total to $2,400 for these with low incomes. In a state the place six out of 10 houses nonetheless warmth primarily with oil, the general aim is to section out warmth methods that use climate-warming fossil fuels, in favor of people who run on renewably generated electrical energy.

Kathy Heseltine stands close to a warmth pump, proper, that was put in in her dwelling via an Effectivity Maine pilot program. Ben McCanna/Workers Photographer

Cell houses are an apt testing floor. Maine has greater than 62,000 models of manufactured housing, in line with U.S. Census information. That represents greater than 8 % of Maine’s housing inventory. The dwellings are essential to offering inexpensive housing in rural communities, and it’s no shock that heating prices are sometimes high of thoughts for the individuals who stay in them. That’s true of Heseltine, who’s retired.

Heseltine stated she will be able to’t tally the financial savings in power prices till yr’s finish, as a result of she pays the identical quantity for electrical energy every month on a cost plan. However Effectivity Maine has calculated that cellular dwelling residents ought to save a mean of $1,300 a yr, in comparison with utilizing oil or propane at present costs.

These financial savings are primarily based on the frugal method that warmth pumps use electrical energy to switch heat current in exterior air to indoor house, even throughout winter, utilizing expertise much like that of a fridge.

Based mostly on prices per unit of warmth, the Maine Governor’s Power Workplace calculates that air-source warmth pumps utilizing electrical energy at 21 cents per kilowatt-hour are inexpensive than oil at $4.44 a gallon, kerosene at $5.09 a gallon or propane at $3.29 a gallon.

“There are many houses in our state that might be terrific candidates for this answer,” stated Michael Stoddard, the manager director of Effectivity Maine. “And other people might save some huge cash.”

Central heating methods in cellular houses typically encompass small, forced-air furnaces that slot in cupboards or closets. Typically referred to as Miller furnaces after a distinguished model, they burn oil or propane and distribute warmth via ductwork.

Swapping out the furnaces wasn’t a straight-forward train within the pilot undertaking, Stoddard stated, as a result of there weren’t any distributors in Maine with a warmth pump unit that match simply into the furnace closets. That elevated the overall price of each research to roughly $14,000 per unit, or $266,000, paid from Effectivity Maine funds. Stoddard stated he expects the associated fee to drop, as extra producers supply models designed for cellular dwelling retrofits.

‘TOASTY WARM’

The pilot undertaking received underway final yr when David Korn, vice chairman at Massachusetts energy-management consulting agency Ridgeline Power Analytics, made a presentation on the cellular dwelling park.

Wardtown Cell Dwelling Cooperative is a resident-owned neighborhood on the agricultural outskirts of Freeport. The neighborhood’s 60 heaps characteristic a mixture of older and newer manufactured houses, and the bulk have furnaces that burn kerosene or propane. An estimated half of the house owners are on mounted incomes.

Marianna Casagranda was at that assembly. As she remembers it, a number of individuals who attended promptly walked out after Korn instructed them their current furnaces could be eliminated for the undertaking. However Casagranda, the Heseltines and eight different house owners have been intrigued by the supply.

Casagranda lives in a 910-square foot single-wide cellular dwelling. It’s solely two years outdated, had a propane furnace and is better-insulated than most older models. However Casagranda stated she noticed the chance to modify to a cleaner heating system that was inexpensive to run.

“I believed, ‘Let’s simply see what it seems like for an entire yr,’ ” she stated. “And I’ve to say, I’m very impressed.”

There have been a number of nights final winter when the surface temperature hovered close to zero, Casagranda stated, however her dwelling stayed at a snug 68 levels. And he or she loved the warmth pump’s air-con operate throughout final summer season’s warmth wave.

She’s additionally blissful along with her power payments. In January 2021, her propane invoice was $189 and electrical energy price $33, for a complete of $222.  Final winter, her electrical invoice that included the warmth pump was $142.

“I’ve been a cheerful buyer,” she stated. “I’ve no real interest in going again to propane.”

The Heseltines’ 1,000-square-foot dwelling isn’t as well-insulated and likewise has a stick-built addition. Kathy Heseltine stated the couple was skeptical coming into Korn’s presentation, as a result of they’d heard “a lot destructive publicity” about warmth pump efficiency.

Final winter modified her thoughts. The home was “toasty heat,” she stated. And being snug in the summertime has been a bonus.

“We by no means had air-con and final summer season was a doozy,” she stated. “In 15-20 minutes, you’re as chilly as you might be.”

These assessments line up with information being compiled by Ridgeline, the guide. The coldest temperature recorded in the course of the trial, at Portland Worldwide Jetport, was 4 levels beneath zero in January.

“We imagine that a few of the native temperatures at (Wardtown) have been truly a number of levels colder,” Korn stated.

“All the houses have been capable of warmth to about 70 levels or to their most well-liked temperature, even in the course of the coldest temperatures, in line with our metering tools and in line with the ten clients who acquired warmth pumps.”

POPULARITY, BUT PUSH-BACK

Increasing warmth pump set up in Maine is a part of the Local weather Motion Plan’s total imaginative and prescient of helpful electrification, the thought of changing fossil fuels for heating and transportation with inexpensive electrical energy generated from photo voltaic, wind and different renewable sources.

This development might be seen in new dwelling development in Maine, in line with a baseline examine performed by Ridgeline.

The examine exhibits a steep decline within the variety of new houses heated with oil between 2015 and 2021, with 20 % of houses now all-electric, with warmth pumps or a mixture of warmth pumps and electric-resistance warmth. Propane, nevertheless, accounts for the biggest single share of new-home heating methods, 45 %.

Propane’s reputation is nice information for the Maine Power Entrepreneurs Affiliation, which represents many oil and propane sellers. The commerce group has been pushing again in opposition to what it sees as a government-directed plan to “electrify all the pieces” on the expense of client selection.

In an interview final summer season with the Press Herald, the affiliation’s president, Charlie Summers, stated Mainers ought to be capable of resolve how one can warmth their houses. A survey performed for the group discovered that 9 out of 10 residents need state insurance policies that permit them select how one can warmth their houses and companies, decisions that will embrace warmth pumps but additionally different choices. The group has been urgent political candidates this yr to take a so-called Power Alternative Pledge, placing them on file as opposing any efforts to limit how Mainers warmth their houses and companies.

On its web site, the commerce group urges warning about relying completely on warmth pumps. Regardless of higher expertise, it says, “warmth pumps are merely not preferrred for climates like ours.”

Effectivity Maine disagrees, and can use the outcomes from its cellular dwelling pilot program to counter that view. However all houses are completely different. And it’s doable, Stoddard stated, that some folks will want or need supplemental warmth sources. One instance may very well be utilizing an electrical house heater to heat a distant, chilly room on the coldest days.

However total, Stoddard stated, the pilot confirms that warmth pumps work in subzero temperatures. He hopes the demonstration will assist clear up public misconceptions in regards to the capabilities of the units.

“Earlier generations of warmth pumps stopped acting at extraordinarily low temperatures,” he stated. “It was affordable for folks to imagine warmth pumps, by themselves, couldn’t present sufficient warmth. However the brand new technology can do this.”

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