Q: I installed heat pumps around 2010. Between November and March, they are MUCH more expensive for heating than my natural gas furnace. Are 2021 heat pumps sufficiently improved that I will be able to use them all winter? Would I need to replace both the indoor unit and the outdoor compressor, or only the latter? What questions do I need to ask to be sure replacing my current units makes sense?

A: If you are using utility electricity at around 23c/kWh then heating with heat pumps will about increase your heating bill about 150% if you had previously been heating with natural gas. This fact never seems to get mentioned by either heat pump installers or heat pump advocates. Even if you are heating with heating oil, your bill will increase about 25% by switching to a heat pump on utility electricity.  The key to cutting your bills AND carbon emissions is to generate cheap solar electricity from your roof. Doing this will cut your heating bill (if you are on natural gas) by about 10% and if you are on heating oil it will cut it about 50%. In either case your heating will now have a zero-carbon footprint. You do not need a new heat pump. You need solar panels.