Canada's climate is really different when it comes to the extreme cold.

Heat pumps are getting better at lower temperatures, but in an environment like Canada you still want auxiliary heat to be safe.

> It should also be noted that although heat pumps are very efficient, even when it's below freezing outside, they cannot raise the temperature of the house very quickly. Consumers are generally quite unhappy when it takes 8 hours to raise the temperature of the house by 1 degree

That would be an undersized heat pump in any regard. The installer would be at fault for screwing up that badly.

You're right that efficiency falls off at lower temperatures, 8 hours to move 1 degree would be from the installer sizing the unit wrong.

It's not just the efficiency of the heat pump that is at issue, it's the insulation of the house. As the outside temperature plunges, the house begins cooling off much more rapidly. This means the reduced efficiency of the heat pump (operating in cold outdoor temperatures) needs to produce more heating than it would at higher temperatures, and it's just not capable of that. My house was built in the 1980s and its insulation has always been more than adequate for the original natural gas furnace to be able to heat.

The heat pump I have is only a few years old and cost $12,000 installed (before tax credits). To be able to rapidly heat the house when it's -40 outside would require a system costing several times that! Much cheaper just to use a furnace for those few days per year.