NWT and Yukon testing cold-climate heat pumps

Two northern initiatives are putting air-source heat pumps to the test, tracking their performance and efficiency throughout cold winters.

One project is run by the Government of Yukon and involves monitoring cold-climate air-source heat pumps in five detached homes in Whitehorse.

The other, organized by the Arctic Energy Alliance (AEA), is tracking heat pumps installed in two housing units in Yellowknife.

Both projects aim to gain insight into how well heat pumps perform in the North’s harsh climate.

Air-source heat pumps – often simply called heat pumps – use a fluid known as a refrigerant to transfer heat from one place to another. In cold weather, that means drawing heat from outdoor air and transferring it to a room indoors or a hot water supply.

“It’s like a reverse refrigerator,” said Mark Heyck, the AEA’s executive director.

A refrigerator takes heat out of the air inside the fridge and expels it through coils at the back. Similarly, Heyck said, heat pumps take thermal energy out of the air and put it into a home’s heating system. In the summer, they can also act as air conditioners.

More: MIT Technology Review’s in-depth heat pump explainer

Because heat pumps are powered by electricity and tend to be highly efficient, they have been touted as a climate-friendly heating solution. Seeing governments providing incentives and hoping to save on utility bills, homeowners have been flocking to the devices. In 2022, annual sales of heat pumps surpassed gas furnaces in the United States, the New York Times reported.

Northerners, however, have been relatively slow to adopt the technology – possibly because of the conventional thinking that heat pumps don’t work that well in cold climates, which may well have been the case in previous decades.

“In the past, they were never considered because they may not be able to heat below, say, -5C,” said Brett Bowman, a technical support representative at Klass Mechanical Sales Ltd, which distributes Mitsubishi heat pumps in Alberta, the NWT and Nunavut.

Since then, Bowman said, the technology has come a long way.

“Now, we can get 100-percent heating capacity out of a heat pump at down to -25C.”

Past that point, he said, the device will start to lose some heating capacity, but it can continue to run in even colder temperatures. Researchers in Alaska, for example, are testing a model that has a cutoff of -35C, as Wired reported.

In the Northwest Territories, where heating still relies heavily on fossil fuels, Heyck says heat pumps have the potential to reduce greenhouse gas emissions – particularly in the South Slave region, which has surplus hydro power.

To better understand heat pumps and make sure that their use is economically and technically feasible in the region, the AEA has undertaken a demonstration project in Yellowknife. Partnering with Housing NWT, workers installed two heat pumps on units in the Sissons Court apartment complex last November.

“The idea is to get basically two years’ worth of data over two heating seasons to determine how well those heat pumps are performing,” Heyck said. Based on that data, the AEA will determine whether they should recommend the technology in the future.

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“There’s not a lot of places in the Northwest Territories that are colder than Yellowknife, so we’re pretty confident that if it works here, it should work just about anywhere,” Heyck said.

The AEA is working with a BC-based company to monitor the heat pumps’ performance. Systems were set up to measure how much heat in each housing unit comes from the heat pump versus the primary heating system.

The team will also gather data on external temperatures and humidity. The aim is to find the point at which the heat pumps lose efficiency and at which reverting to the primary heating system makes more sense, Heyck said.

Another of the demonstration project’s goals is to increase contractors’ familiarity with the technology. To that end, the AEA held a virtual workshop about cold-climate heat pumps earlier this month.

Heyck said the workshop was the most well-attended of the organization’s sessions so far. “There’s clearly a lot of interest in it,” he said.

Throughout the past winter, the heat pumps installed in Yellowknife have experienced a range of temperatures. Although their performance has yet to be determined, Heyck said that, anecdotally, at least one of the tenants who had a unit installed “really, really likes it.”

The AEA expects an interim report in May or June on the project’s first six months. Another report will be produced at the 12-month mark, Heyck said.

“I’ll be very curious to see how it worked out.”

Installation matters

Although the Yellowknife project is only a few months in, a pilot project in Whitehorse has been tracking heat pumps’ performance for several years.

The project came out of the territory’s climate change, energy and green economy strategy, which committed to shifting from fossil fuel-based heating to heating with renewable sources, said Karine Smith, an energy program officer at Yukon’s Department of Energy, Mines and Resources, in a presentation during the AEA’s workshop earlier this month.

To gauge heat pumps’ viability and encourage uptake, Smith said the territory developed a pilot program to test their operation, energy savings and performance in real-world Yukon conditions.

In 2020, the Yukon government started monitoring five units installed in detached homes in Whitehorse. So far, the government has published two reports outlining its findings.

From April 2021 to April 2022, the five heat pumps’ coefficient of performance or COP – a measure of energy efficiency and performance – ranged from 1.02 to 2.41, according to the territory’s latest report. At moderate temperatures, some units’ COP surpassed 2.

This means the heat pumps are more efficient than heating systems such as electric furnaces and baseboards, which have a COP of 1, the territory reported.

Only one heat pump functioned close to the efficiency specified by the manufacturer, however, Smith said. Four heat pumps operated at an efficiency about 33 percent lower than the manufacturer’s specifications.

The report stated this reduced efficiency may be related to problems with ductwork.

Fossil fuel heating systems provide hotter air compared to heat pumps, Smith said, so they require less airflow and smaller ducts. Heat pumps, in contrast, produce slightly cooler air but require more airflow to heat a home to the same temperature, she said.

“Many existing homes were built for fossil-fuel heating systems and the ducting is slightly small,” Smith said. As a result, the territory recommends that homeowners looking to get a centrally ducted system installed have a duct assessment conducted.

Energy savings for all the heat pumps ranged between two and 43 percent, Smith said.

“While challenges were found during this initial pilot project, air-source heat pumps can function more efficiently than electric furnaces, boilers or baseboards,” she said, adding that the findings highlight the importance of proper design and installation.

The Yukon government is now entering the second phase of the pilot project. Another 18 heat pumps of different styles should be installed in the spring, Smith said. The team intends to continue monitoring all the units until 2025.

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This article is produced under a Creative Commons CC BY-ND 4.0 licence through the Wilfrid Laurier University Climate Change Journalism Fellowship.