I can't imagine using boiling hot water ever on a frozen-in car, particularly if it got on the windows, some of which are pre-stressed and I suspect would then shatter into a million skin-friendly tiny crystals. But that would lead to driving with wind-burn!

Alaskans are encouraged to plug-in their vehicles. Many are purchased with these electrically heated plugs which fit into the engine block. In Fairbanks most hotels come with receptacles in the parking lot. On the North Slope it is standard. You either plug-in at the bullrail or leave it running during the three quarters of the year when you need to.

I drove up to Alaska a couple of times with outside vehicles and installed the block heaters myself, but I was lucky. It is safer to have it done by someone with experience.

There are Teslas up here but I don't know if they are a good idea for those who do a lot of outside the garage parking. Batteries lose power when they are cold.