Electric and alcohol
We use BOTH types of heaters -- electric and alcohol. I installed shore power so that we could heat the boat (even summer evenings are chilly in the Puget Sound area) when in a marina. We have a tiny electric heater which keeps the cabin quite comfortable. It can be set to come on some number of hours later, so we can have a warm cabin to get up to in the morning. For when we don't have shore power, I got an alcohol heater. It uses the same fuel as the alcohol cook stove. It actually puts out more heat than the electric heater and can double as an additional cooking burner -- especially with a wok or skillet.
