I live in an area where hot water heating is common. Hot water heaters have secondary loops through the main oil-fired boiler and these could easily be made ele

I live in an area where hot water heating is common. Hot water heaters have secondary loops through the main oil-fired boiler and these could easily be made electric. A missing link is indeed a cinder block energy storage pile that could be set to preheat water going into the hot water boiler, or to cycle through water going into heating.