Heat pumps are designed to operate when it’s still cold out. Really cold out.

Two years ago, the mercury dipped well below zero, significantly colder than this week. The Globe reached out to heat pump owners to see how their systems fared in the bitter cold in February 2023. Here’s what we found.

Greenhouse gases produced by heating buildings, including homes, account for about a third of Massachusetts’ climate-warming emissions.

Ben Butterworth, the director of climate, energy, and equity analysis at the clean energy advocacy organization Acadia Center, said he wasn’t surprised that heat pumps performed well. “After years of falsely being told that heat pumps weren’t suitable for extreme cold, I do think this moment was critical for instilling confidence in heat pump users,” he said. “Continued reliance on fossil fuels to heat our buildings is simply incompatible with the state’s climate targets.”

To read the full article from the Boston Globe, click here.