Sales are growing so quickly that some installers wonder whether heat pumps could even wipe out the demand for new air conditioners in a few years and put a significant dent in the number of natural gas furnaces.
We had one professionally installed in our previous rural house. It was great most of the time, only really an issue when it hit -25C. However, we didn't use it as our primary heat...that was propane.
I appreciate that the article notes that households on the prairies and other colder areas often retain their gas furnaces the coldest periods - particularly as the electricity costs to run the heat pump in those periods outweigh the cost of gas.
I took the lesson to be that it’s best not to wait until your gas furnace has to be replaced but rather to replace the air conditioner and save the remaining life of the furnace for the deep cold periods when it’s energy inefficient and more expensive to use the heat pump. It would be great to see some good analysis/modelling of this.
A friend of mine just had a new heat pump/furnace combo installed. It has a single controller for the whole system (is my understanding), so the heat pump will run normally and the furnace will kick in if needed. I can't recall the details of when exactly the furnace kicks in.
That is how mine works. You can also get a rig that will slightly heat the air inside the heat pump to let it operate at much lower temperatures than normal. Supposedly more efficient than using the furnace.