Tankless Water Heaters: Gas vs. Electric Efficiency

LESLIE: David in Delaware has a water heater question. What can we do for you?

DAVID: Yes, I have electric – total electric in my house and I heard about the tankless water heaters [1]. But I was wondering whether or not electric [2] would be very efficient.

TOM: Actually not, David, because gas tankless water heaters are fantastically efficient [3]; electric tankless water heaters, not so much. So if you have electric, what we would recommend is a super-insulated tank-style water heater [3]. There are different manufacturers that have this type of model. I think Rheem has one called Marathon [4], if I remember correctly, that has a very thick wall of insulation. That, coupled with a water heater timer [5] so it only comes on …

LESLIE: When you need it.

TOM: … when you actually need it would be the best way to cut your electric water-heating costs [6]. Gas is fantastic for tankless but not electric, because you just can’t deliver enough power to do the job.

DAVID: Where would you get the timers?

TOM: Well, the timers are available at any electrical supply store or home center. You just want a 240-volt timer.

DAVID: OK. Very good.

TOM: Usually gets installed right near the water heater and you want to set it to come on for a few hours in the morning when you need it for showers and that sort of thing; few hours in the afternoon and evening; then it can go off for the rest of the time. The water will stay warm in the water heater. As long as you’re not using a lot of it you’ll be good to go.

DAVID: Very good.