Juneau gets most of its electricity from lakes, which are clean hydroelectric resources. This means that it is particularly environmentally friendly to install electrified heating systems in the city.
But to be fair, Juneau is in the warmer end of the state and doesn’t tend to experience the same brutally cold winter weather that can plague places up north like Anchorage or Fairbanks, where heat pumps can be less cost-effective.
In the village of Eklutna, near Anchorage, electrician Derek Lampert found a heat pump that can handle extreme temperatures. He lives in the house he built with his father during the pandemic. The walls are 22 inches thick, he boasts. Lampert planned to make the house as energy efficient as possible, so he invested in a SANCO2 heat pump that uses CO2 for 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 was getting 135 degree water.”
High efficiency was definitely Lampert’s goal, and overall he’s pleased with the results. At least financially, a well-insulated house and the installation of a heat pump turned out to be beneficial. “People in my area spend more [than my entire electricity bill] on propane and fuel oil,” says Lampert.
However, because the heat pump draws indoor heat from the outside, sometimes over a long period of time, the outside of the machine can become particularly cold and make the unit less energy efficient. Heat pumps are generally designed for intermittent defrosting, but Lampert claims his model may be better at that. He says he has noticed a significant amount of frost and ice around his heat pump when it is very cold. “Certainly, the colder it is, the worse it is. It just fights with all the moisture,” he explains.
John Miles, a spokesman for Eco2 Systems LLC, which makes SANCO2 heat pumps, says the current model operates down to -26 degrees Fahrenheit (-32 degrees Celsius). He adds that he has various means of checking for frost accumulation 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 in temperatures down to -13 degrees Fahrenheit (-25 degrees Celsius), cannot operate during the winter months. “It doubled the power consumption when I used it at very low temperatures,” he says. When the temperature drops below 0 degrees Fahrenheit, it switches back to the oil heating system.
Vanessa Stevens, a research scientist at the National Renewable Energy Laboratory in Fairbanks, says the latest heat pumps are becoming more frost-resistant.
“This spring, we’re actually testing a heat pump in our lab where the shutdown temperature is -31 degrees Fahrenheit,” she says. “That was unheard of 10 years ago.”
Demand in Alaska appears to be increasing significantly because heat pumps are becoming more efficient and cost-effective, she suggests, adding that there are now companies that specialize exclusively in installing heat pumps, a relatively new development.
Heat pumps have great decarbonization potential, but it depends on the context, says Meredith Fowley, an economist at the University of California, Berkeley. They will be most useful as a climate solution when they run on electricity generated predominantly from low-carbon sources and when manufacturers move away from the least climate-friendly refrigerants of heat pumps. According to Fowley, new homes or homes that require a completely new heating system should choose a heat pump as standard. But as heat pumps continue to spread, there must be enough trained professionals to install them, as well as building codes that encourage the use of more efficient systems, Fowley says.
“There is a sense of urgency that needs to be balanced with some practical, pragmatic challenges that we need to overcome.”