Survey Results: How Well Did Your Heat Pump Heat During the Polar Vortex? 

On February 9, 2023 we posted the following query to Front Porch Forum in Middlebury:

We here at the Climate Economy Action Center of Addison County are curious to know for those of you who heat your homes with heat pumps how they fared during Saturday’s frigid temperatures.

  1. How do you heat your house?
  2. How well did your heat pump work during  the frigid weather on Saturday?
  3. Overall,  what is your current opinion about your decision to heat with a heat pump?


We had 46 people respond to the survey. Here’s what we learned:

How do you heat your house?

Of the 46 respondents:

  • About one third of respondents heat their home entirely with heat pumps
  • About 11% of respondents heat their home mostly with a heat pump 
  • The remaining 56% heat partially with a heat pump.

How well did your heat pump work during  the frigid weather on Saturday?

When asked how well the heat pumps worked during the frigid weather, the 20 respondents who rely entirely or mainly on heat pumps reported that:

  • ⅓ of them said it worked fine and they did not have to rely on a back-up heat source
  • ⅔ said that the weather was too cold and they had to use a back-up heat source to help heat the house until it warmed up the next day

Overall,  what is your current opinion about your decision to heat with a heat pump?

When asked about their decision to heat with a heat pump, respondents were overwhelmingly happy or very happy with their decision to use heat pumps. This was true both for those who use heat pumps as their primary heat source, and those who use them as a supplemental heat source. 31 of the 46 respondents believe their decision to install a heat pump was a good decision, 

Good DecisionPoor Decision


Overall, it is encouraging that the vast majority of responding heat pump owners are quite happy with their decision, even when many used a backup source during this very cold night and day. 

In reading the comments, it is clear that many have a back-up heat source for extremely cold conditions, even though it is used very rarely.  The decision to have and to use a backup heat source is in part driven by homeowners’ tolerance for some period of cold temperatures in their houses.  How long it takes a house to cool off to an uncomfortable temperature when it is too cold for the heat pump to function depends on how tight and well-insulated the home is.  Some respondents reported confusion and conflicting advice about just what to do with your heat pump when it gets very cold. To fully understand the results, it would have helped to learn more about the age of the home, the amount of weatherization, the age of the equipment. It would also be interesting to learn more about was the equipment installed by the home owner or by the landlord, as well as information about whether or not the heat pump has over time saved money. 

Since this informal survey is far from a scientific study, it is worth reading a recent NY Times article on how heat pumps perform in cold weather As Heat Pumps Go Mainstream, a Big Question: Can They Handle Real Cold? ( ) The article shows the growth in the number of heat pumps in the US, documents the cost and environmental savings associated with them, and points to improvements in the technology that allow them to function effectively even in the coldest of climates.  Cold-climate heat pumps sold today will function down to  -18 to -20 degrees F. A similar article in the Boston Globe Heat pumps had their first major local test last weekend. Here’s how it went. ( ) tells much the same story.

Comments from Respondents

Here are selected comments from respondents. It is possible that some of our respondents have older heat pumps that lose effectiveness at higher temperatures, like 5 or 10 degrees F instead of -18. 

  • Other than the one evening of severe cold, the system is more than adequate to efficiently  heat and cool our home.  
  • First time in five years that the backup has been needed. 
  • Only had to use backup for a few hours. Worked much better than expected!
  • I have 34 solar panels and feel good that I can heat mostly from energy gathered on my roof.
  • Heat pumps are great, but I’m glad I had another source to supplement during the bitter cold. They just don’t work well at -20 degrees. 
  • The house was 48 degrees when I got up that morning, so I turned on the oil furnace and my propane stove in the sunroom to catch up.  99% of the time, I don’t need either of those, but when it goes much below zero, it’s a good idea.
  • The heat pump was my sole source of heat until the temp went below 10 degrees. Then I found it necessary to turn on my oil-fueled heat via my boiler.
  • We combine it with my oil hot water system.  Heat pump was still producing heat during frigid temperatures. Oil consumption has definitely decreased since heat pump installation.  
  • I feel the heat pump saves me money about 95% of the time. And with my grid-tied PV solar array installed at the same time, it’s cleaner energy than the fuel oil I otherwise burn.
  • I love my heat pump. I was impressed with how well it worked in those temps!
  • We ran our oil furnace to keep radiator pipes on outer walls from freezing
  • The heat pumps did just fine all the way down to Zero but when the temperature dipped below zero I had to resort to the furnace.
  • We heat with heat pumps and wood and are happy with that, but we’re not ready to take out the baseboard system just yet.
  • I love them! 
  • I just bumped it several degrees up and it could have kept up. I didn’t really need the secondary source but turned it on to ease the stress on the heat pumps
  • We use our heat pumps for heating down to about +15 degrees F.  If colder than that, they are much less efficient so we prefer to switch over to our primary heating system (natural gas).
  • It’s 8 years old. a slow leak over the years made efficiency go gradually down to no heat….Now getting a new one (2 heads , like the first one), and changing location of heads to EXTERIOR WALLS. ….. Overall, BETTER THAN USING FOSSIL FUELS.
  • I got a small amount of warmth from the pump when really cold but even with a wood stove going too it was only about 62 in the main living area. 
  • My decision to heat with cold climate heat pumps was good, but I definitely needed a back up system and last weekend proved it.  The pumps literally would not work and needed to be shut down.  They were also using the most electricity they ever have (resistance heat).
  • Back of house only heated with heat pump.. needed to use extra heater on Sat in one room. Other room very new construction and held the heat better..
  • When the temp goes below positive 5 degrees,  we turn it off and let the propane furnace heat the house.  This has only happened five or so days/year in our four years of experience.

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