Much of Juneau’s electricity comes from lakes that provide clean hydroelectric resources. This means that installing electrified heating systems in cities is particularly environmentally friendly.
But, to be fair, Juneau is on the warmer end of the state and doesn’t experience the harsh winter weather of places further north like Anchorage or Fairbanks, where the cost-effectiveness of using a heat pump might be lower.
In the village of Eklutna, not far from Anchorage, electrician Derek Lampert discovered a heat pump that could handle extreme temperatures. He lives in a house he built with his father during the pandemic. He boasted that the walls were 22 inches thick. Lampert planned to make the house as energy efficient as possible, so he invested in a SANCO2 heat pump, which uses CO2 for the refrigerant. The machine provides space heating and hot water supply.
“We had sub-zero degrees Fahrenheit, and it worked,” Lambert said. “I get 135-degree water.”
Efficiency is of course the goal for Lambert and overall he is happy with the results. Well-insulated homes and heat pump setups have proven beneficial, at least financially. “People near me spend more [than my entire electricity bill] on propane and heating oil,” Lambert said.
However, because heat pumps draw heat from the outside, sometimes for extended periods of time, the outside of the machine can become extremely cold, reducing the energy efficiency of the unit. Heat pumps are usually designed to defrost themselves on a regular basis, but Lambert thinks his model could do a better job at this. He said he noticed frost and ice forming on the outside of his heat pump when it was very cold. “Of course, the colder it gets, the worse it gets. It’s just fighting all the moisture,” he explains.
John Miles, a spokesman for Eco2 Systems LLC, which makes the SANCO2 heat pumps, said current models operate in temperatures as low as –26 degrees Fahrenheit (–32 degrees Celsius). It has multiple ways to check for frost, and any ice that forms will eventually melt, he added.
Terry Chapin, an ecosystem ecologist and professor emeritus at the University of Alaska Fairbanks, has a heat pump, but notes that his model is designed to operate in temperatures as low as –13 degrees Fahrenheit (–25 degrees C), making it difficult to run in winter. response. “When I use it at very low temperatures, it doubles our electricity usage,” he said. When the temperature dropped below 0 degrees Fahrenheit, he switched to an oil heating system.
Vanessa Stevens, a building science researcher at the National Renewable Energy Laboratory in Fairbanks, said the newest heat pumps are increasingly hardy.
“We were actually testing the heat pump in the lab this spring, and it had a cutoff temperature of –31 degrees Fahrenheit,” she said. “This was unheard of 10 years ago.”
Demand appears to be growing strongly in Alaska as heat pumps become more efficient and cost-effective, she said, adding that there are now companies that specialize in heat pump installation — a relatively new development.
Meredith Fowlie, an economist at the University of California, Berkeley, said heat pumps have a lot of decarbonization potential, but it depends on the situation. They will be most beneficial as climate solutions when they run primarily on electricity generated from low-carbon sources, and when manufacturers ditch the least climate-friendly heat pump refrigerants. Fowlie says new homes, or those that need an entirely new heating system, should now opt for a heat pump as standard. But as heat pumps continue to grow in popularity, there must be enough properly trained tradesmen to install them, as well as building codes that promote the use of more efficient systems, Fowlie said.
“There is a sense of urgency that needs to be balanced against some real, pragmatic challenges that we need to overcome.”
