When my husband and I moved in together, we rented an apartment which we didn’t realize had only baseboard electric heat. Our unit is in an old house and we live in MN, and that winter we had a string of -30 or -40 degree days.
The first month of that, our electric bill jumped to over $400 dollars. We were very surprised by that bill, and I was cold all the time. Luckily the next month the landlord put in a gas furnace, or I don’t think we would have made it. (it also probably wasn’t legal/sufficient heating in our area, but vacancy rates were super low and we were hesitant to raise the “this is illegal” issue).