Newbie here, but have read lots of posts. Need your advice on designing the best setup for heating water at my folks' house.
Current hot water and heating in the house (northeastern Pennsylvania) is an oil burner and a coal burner. The coal burner operates about 6 months a year to provide heat to the house by pumping water up through the radiators. The oil burner can provide steam heat to the house, but it is used for that purpose only when they leave on periodic vacations throughout the winter. The rest of the year, it provides hot water to the house through it's tankless system. Not very efficient, especially with oil prices now at ~$3.70/gallon, it basically costs about $2,000+/year for hot water.
Total heating costs for the winter are ~$400 for coal. That's it. And even with that, they sometimes have doors open.
They want to keep the oil burner to prevent the house from freezing in the winter while they are away periodically and need to let the coal burner go out.
So the water heater alternatives as I see them are to:
1) install an electric tank only for full-year use
2) install an electric and an indirect in series or parallel, getting heat from the coal burner, each getting used 6 months/year
3) install an indirect with a built-in electric element (if they make such a thing)
Am I missing any other options? I've searched online, but haven't been able to find any indirect heaters with an option for a built-in electric element. Are they out there?
There is no gas service, and I am doubtful the up-front costs of an electric on-demand heater is worthwhile.
Any comments / suggestions are most welcome.