[paul_f]

The COP for a heat pump drops as the temperature decreases. The climate should have a large impact on the choice of technology. Here in Florida it is a no brainer, everyone has a heat pump for the cool winter days. In Minnesota, it is a non starter.

[francisofascii]

The article is pointing out that heat pumps today can still be more efficient down to -20 C (-4F).

[sbradford26]

It depends on what else you have available. If you have natural gas available at your house then a heat pump is probably not the most economical choice. Here in New Hampshire though NG is not available at many homes and a cold weather heat pump ends up being the cheapest option versus heating oil or propane.