The Myth of Failing Heat Pumps in Subzero Temperatures

There’s been a lot of buzz around heat pumps lately—both good and bad. So we wanted to set the record straight about why we recommend heat pumps and how they stood up during the arctic blast we just experienced. 

First, rest assured that our customers have reported that the heat pumps we installed worked as planned. If a home is airtight and properly insulated, there should be no concerns about the heat pumps failing. The issues we have heard about are when people turned off the heat pump (in response to the media reports that heat pumps would fail in these sub-zero temperatures) in favor of using their auxiliary heat only to find these couldn’t work due to frozen pipes where there were thermal bridges or air leaks.

After the deep freeze, The Boston Globe surveyed heat pump users to see if they kept up with the cold. This is what they found:

“As temperatures began to fall on Friday, the Globe asked heat pump users via Twitter and an online survey to report how their pumps performed as the worst of the cold hit. More than 450 responded, and most said their pumps kept their living spaces as warm as they wanted … And the best experiences were reported by people who had installed heat pumps intended for cold climates and whose homes were well-insulated.”

One of our clients, Jackie J., confirmed that the heat pumped worked well during the recent cold snap, especially in areas where we had added insulation:

“We recently converted our 1950s home to cold climate air-source heat pumps to replace the oil-fired boiler. We have found them to provide extremely comfortable heat (and air conditioning). Many asked how they held up in the recent -14 degree cold snap, and whether we regret ditching the boiler. The heat pumps had no trouble keeping up. In half our house where we have insulated the attic and floor, the temperature never dropped inside. In the other half of the house, where we have not yet insulated the ceiling, it dropped a few degrees overnight but recovered in the morning. This reinforced the advantage of doing heat pumps and insulation together, and gave us the confidence to ditch the boiler and fully embrace electrification. We have since also installed a hybrid heat pump water heater and now our home is fossil-fuel free!”

With that myth busted, we want to explain why steveworks recommends heat pumps. The short answer: it helps mitigate the effects of climate change and in every renovation we keep that principle in mind. 

Here’s the longer answer. Air source heat pumps use a refrigeration circuit to extract energy from the ambient air and deliver it as heat. As proven recently, today’s heat pumps can operate effectively even in extremely hot and cold conditions, making them a reliable way to efficiently heat and cool a home in the Boston area. 

As far as efficiency, a heat pump can generate 4.5 watts of heat for every 1 watt of electricity. Even the most efficient gas-fired boilers and furnaces produce 0.9 watts of heat for every 1 watt they consume. Not to mention that heat pumps result in fewer carbon emissions than natural gas, despite gas being dubbed a “clean” fuel. Plus, with the regional and national electric grid continuing to transition to renewable energy, there can be economic incentives for homeowners to adopt electric heat pumps, including rebates through the MassSave program.

With the benefits of healthier air, home comfort, energy efficiency, and lowering our carbon footprint, we love to recommend heat pumps. And, you can rest assured, they have proven that they will perform even in the coldest of temperatures.