Yes, if you choose a cold-climate model and size it properly. In Natural Resources Canada field tests, a cold-climate heat pump still averaged a COP of about 1.5 at -21 C, so it made more heat than a baseboard heater using the same power. It loses capacity as it gets colder, so homes in the Interior and the North usually keep a backup (electric coils or a furnace). Ask your installer for a heat-loss calculation for your home.