Tankless Water Heaters: Energy Efficient?

Find out if tankless water heaters are as energy efficient as you may think. In most homes, a tankless water heater can save energy and money.

LESLIE: Greg in Illinois is thinking about a tankless water heater. How can we help you with your decision?

GREG: Yes. Hello. I just want to say I love you guys’ show.

TOM: Thanks.

GREG: Great. Our home, it was built in 1997. We got a 2000 waterless – a tankless water heater.

TOM: OK. Yeah, it’d be hard to have a waterless heater, wouldn’t it, Greg?

LESLIE: I’m like that would be amazing.

TOM: You’d save a lot of water but you wouldn’t get very clean. (chuckles)

GREG: (chuckles) It’s just a two-story home and it runs two to three minutes before any hot water comes on.

TOM: OK.

GREG: So the bath – they’re both on the second floor.

TOM: Right.

GREG: So we don’t understand how this is energy efficient when you’re wasting the water.

TOM: Yep. Sure. Well, the fact that you have a tankless water heater means that you are heating the water very efficiently. The fact that you have to wait two to three minutes for the water to get hot is something that would happen regardless of whether you had a tank or a tankless unit by virtue of the fact that you have a certain distance between the plumbing fixtures in the bathroom and where that water heater is located.

Now, the advantage that a tankless water heater would give you would be that because these units are so small and easy to install, you could actually zone the hot water in your house and have a second tankless water heater on the second floor, nearer to the baths; and in that case, you would get water rather instantly, as soon as you turn it on. But if you simply have to push out all of the water that’s in the pipes from the basement to the second floor, that’s going to take a couple of minutes to get hot and that is an inefficiency you would have regardless of what type of appliance you have. You understand?

GREG: I understand. Yeah, that makes total sense. Yes. Thank you very much for you guys’ time. I really – that helps me out a lot.

LESLIE: And Greg, you know what you can do so you don’t feel so guilty about that water? You can take some pitchers and fill them up with that water and use it to water the plants.

GREG: There you go. (laughs) That’s a good idea.

TOM: Alright, Greg, we’ve got several articles about tankless water heaters online at MoneyPit.com. Thanks so much for calling us at 1-888-MONEY-PIT.