Juneau gets most of the electricity from lakes providing clean hydroelectric power. This means that installing electric heating in the city is particularly environmentally friendly.
But, to be fair, Juneau is at the warmer end of the state and doesn’t tend to experience frigid winter weather that could affect places further north like Anchorage or Fairbanks, where pumps are used. Heat may be less effective.
In the village of Eklutna, not far from Anchorage, electrician Derek Lampert found a heat pump that can cope with extreme temperatures. He lives in a house he built with his father during the pandemic. The walls are 22 inches thick, he boasted. Lampert planned to make the house as energy efficient as possible, so he invested in a SANCO2 heat pump, which uses CO2.2 for a refrigerant. The machine provides space heating and hot water supply.
“We let it get as cold as -20 degrees Fahrenheit and it worked,” Lampert said. “I got 135 degree water.”
High efficiency is certainly Lampert’s goal and overall he is satisfied with the result. Financially, at the very least, a well-insulated house and a heat pump setup proved beneficial. “People in my neighborhood spend more [than my entire electricity bill] on propane and hot oil,” says Lampert.
However, because heat pumps draw heat from the outside into the home, sometimes over long periods of time, the outside of the machine can become especially cold and make the unit less efficient. Heat pumps are typically designed to periodically defrost themselves, but Lampert argues his model can do better than this. He says he’s noticed quite a bit of frost and ice accumulating around the outside of his heat pump when it’s very cold. “Certainly, the colder it is, the worse the illness. It just struggles with all the moisture,” he explains.
John Miles, a spokesman for Eco2 Systems LLC, the company that makes SANCO2 heat pumps, says the current model operates at -26 degrees Fahrenheit (–32 degrees Celsius). He added that it has various means of checking for frost buildup, and that any ice that forms will eventually melt.
Terry Chapin, ecosystem ecologist and professor emeritus of the University of Alaska, Fairbanks, has a heat pump but notes that his model—designed to operate at -13 degrees Fahrenheit ( –25 degrees Celsius)—very difficult during the winter months. “It doubles our electricity usage when I use it at very low temperatures,” he said. When the temperature drops below 0 degrees Fahrenheit, he turns to his oil heating system instead.
Vanessa Stevens, a building science researcher at the National Renewable Energy Laboratory in Fairbanks, says that the latest heat pumps are becoming increasingly rugged.
“We were actually testing a heat pump in our lab this spring with a threshold temperature of –31 degrees Fahrenheit,” she said. “That was unheard of 10 years ago.”
She suggested that demand in Alaska seems to be growing as heat pumps are becoming more efficient and cost-effective, adding that there are now companies that specialize solely in heat pump installation — a relatively new development.
Heat pump has great decarbonization potentialThis depends on context, says Meredith Fowlie, an economist at UC Berkeley. They will be most beneficial as a climate solution when they run on electricity generated primarily from low-carbon sources—and when manufacturers move away least climate-friendly heat pump refrigerant. According to Fowlie, new homes or homes that require an entirely new heating system should opt for heat pumps as standard now. But as heat pumps continue to spread, there must be enough trained workers to install them, as well as develop rules that promote more efficient use of systems, Fowlie said.
“There’s a sense of urgency that needs to be balanced against some of the real, pragmatic challenges we need to overcome.”
