Just replaced oil + some electric baseboards with heat pumps + the same electric baseboards. However, when it got down to -5F or so the heat pumps and baseboards were only able to keep the house at around 60F.

The main problem is the house leaks like a sieve. Even with oil it would get cold. I had a brief power outage on a cold day and it caused a 7F drop in temperature in like an hour. Now I've got to go through and seal up all the holes and air leaks and missing storm windows.

Even with the leaks, the heat pumps have so far saved me hundreds of dollars per month over last winter's oil.