Juneau gets most of its electricity from lakes that provide a clean source of hydropower. This means that it is particularly environmentally friendly to install electrified heating systems in the city.
But to be fair, Juneau is on the warmer side of the state and doesn’t tend to experience the same blisteringly cold winter weather that can hit places further north, like Anchorage or Fairbanks, where using heat pumps could be less cost effective. are.
In the village of Eklutna, not far from Anchorage, electrician Derek Lampert has found a heat pump that can withstand extreme temperatures. He lives in a house he built with his father during the pandemic. The walls are 22 centimeters thick, he boasts. Lampert wanted to make the house as energy efficient as possible, so he invested in a SANCO2 heat pump, which uses CO2 for a refrigerant. The machine provides space heating and hot water supply.
“We’ve had it down to -20 degrees Fahrenheit and it still worked,” says Lampert. “I got 135 degrees of water.”
High efficiency was certainly Lampert’s goal and overall he is pleased with the results. From a financial point of view, the well-insulated home and heat pump setup have certainly yielded benefits. “People in my neighborhood spend more [than my entire electricity bill] on propane and fuel oil,” says Lampert.
However, because a heat pump draws heat in from the outside, sometimes over long periods, the outside of the machine in particular can get cold, making the unit less energy efficient. Heat pumps are generally designed to defrost themselves periodically, but Lampert argues his model could be better at that. He says he’s noticed a fair amount of frosting and icing around the outside of his heat pump when it’s really cold. “Certainly, the colder it gets, the worse it gets. It just struggles with all the moisture,” he explains.
John Miles, a spokesperson for Eco2 Systems LLC, which makes the SANCO2 heat pump, says the current model works down to -26 degrees Fahrenheit (-32 degrees Celsius). He adds that it can check for ice formation in several ways and that any ice that forms will eventually melt.
Terry Chapin, an ecosystem ecologist and professor emeritus at the University of Alaska, Fairbanks, has a heat pump, but notes that his model — designed to operate down to -25 degrees Celsius — struggles in the winter months. “It doubled our electricity consumption when I used it in very low temperatures,” he says. When the temperature drops below 0 degrees Fahrenheit, it switches back to its oil heating system.
Vanessa Stevens, a building sciences researcher at the National Renewable Energy Laboratory in Fairbanks, says the latest heat pumps are becoming increasingly hardy.
“We’re actually testing a heat pump in our lab this spring where the cutoff temperature is -31 degrees Fahrenheit,” she says. “That was unheard of 10 years ago.”
Demand in Alaska appears to be rising sharply as heat pumps become more efficient and cost-effective, she suggests, adding that there are now companies dedicated solely to heat pump installations — a relatively new development.
have heat pumps high decarbonization potential, but it depends on the 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 from the least climate-friendly refrigerants for heat pumps. New homes, or homes that require a brand new heating system, should now opt for a heat pump as standard, according to Fowlie. But as heat pumps continue to proliferate, there should be plenty of well-trained tradesmen to install them, as well as building codes that promote the use of more efficient systems, says Fowlie.
“There’s a sense of urgency that needs to be balanced against some of the practical, pragmatic challenges we have to overcome.”