Yes but by a weird coincidence most of that heat can be provided by heat pumps at a similar 3-5x ratio.
reply(it's not a coincidence, it's the exact opposite formula. You can only get 20% out of a certain heat engine because running it in reverse would be a 500% efficient heat pump, and the closed loop can't be more than 100%. This still applies even if the engine isn't built to be able to act as a heat pump, because some other engine could.)
replyMaybe, but that other 70-80% is waste - we could turn it into useful heat, but instead we vent it to the environment.
replyI've seen plans to run an engine in your furnace, thus creating both electric (at 20-30%, and capturing the rest as heat to the house. I've never seen this in the real world and experts who have looked as those systems said they won't enter a building that has one using that design. (it is possible to make a design they would trust, but they haven't seen any)