The best one reaches 1:1 when approaching -35C, which means that they're as efficient as resistive heaters. So you save nothing in electricity costs, and if all

The best one reaches 1:1 when approaching -35C, which means that they're as efficient as resistive heaters. So you save nothing in electricity costs, and if all your days are that cold then the $3000 you invested in the heat pump is wasted (that's how much a quality pump with installation will cost you in the Nordic countries - it seems to be much more expensive in North America, at least that's what the comments appear to indicate). If you have warmer days now and then then you'll start saving money, and eventually it'll pay for itself. Where I live (cold winters), the cost was covered in only two years.