Tankless water heaters: pros and cons

After debating the pros and cons of on-demand or tankless water heaters, a couple concludes that the environment is the deciding factor.

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    Sheep Dog Hollow is a 1902 farmhouse in Connecticut that is being renovated with both the environment and the family budget in mind. Currently being decided: tankless water heaters or conventional ones?
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One of the great gifts in undertaking this attempt to renovate Sheep Dog Hollow in a green and economical manner is the way the project has changed and challenged the way I think.

So many things that I used to take for granted – water, for instance, both hot in the house and cold out in the pond – I look at quite differently. I see now – in a way that I hadn’t before – that it’s imperative to protect and conserve both whenever possible to ensure that they’ll be plenty for generations to come – even if it’s going to cost me a bit more upfront.

Recommended: Think you know the odd effects of global climate change? Take our quiz.

I know, I know, I’m an antediluvian greenie newbie who should have known that all along. But as I mentioned about the “green intimidation factor," some of us just didn’t get it before.

That brings me back to the discussion of tankless water heaters and the bottom-line, cost-benefit analysis approach to them that prompted Consumer Reports magazine to conclude that it’s “probably not” time to switch from conventional models. The reason is that they’re “efficient but not necessarily economical," primarily because their upfront costs are so much higher than conventional-storage water heater tanks:

The tankless water heaters we tested cost $800 to $1,150, compared with $300 to $480 for the regular storage-tank types. Tankless models need electrical outlets for their fan and electronics, upgraded gas pipes, and a new ventilation system. That can bring average installation costs to $1,200, compared with $300 for storage-tank models.

By their calculations, a tankless model is “22 percent more energy-efficient” than a conventional one, which translates into “a savings of around $70 to $80” a year. But “it can take up to 22 years to break even — longer than the 20-year life of many models.”

The article also mentions a survey that found a common complaint among users of the tankless water heaters was their production of “inconsistent water temperatures.”

When you turn on the faucet, tankless models feed in some cold water to gauge how big a temperature rise is needed. If there's cool water lingering in your pipes, you'll receive a momentary "cold-water sandwich" between the old and new hot water. And a tankless water heater's burner might not ignite when you try to get just a trickle of hot water for, say, shaving.

I’ve used an on-demand, gas-fired water heater for years in Italy and did find some problems, but inconsistent temperature was not one of them. In the kitchen, where the tankless heater is situated, I turn on the water, it runs for a moment or two, and I have plenty of stable, hot water.

Here in the States, where we have a conventional tank, I also have to wait a moment or two after turning on the water fo rit to come out of the faucet heated to my desired temperature. That’s because it also has to travel from the tank through some pipes that still have cold water in them to get to the faucet. I don’t understand why Consumer Reports chose to ‘diss” tankless water heaters for a problem that’s just as common with conventional ones.

As for the complaint about a tankless burner maybe not igniting when there’s just a trickle of water, when you run just a trickle of water out of a faucet connected to a conventional tank, it also comes out cold for a long time before heating up.

When Martin shaves, occasionally he turns on the hot water until it gets to a good temperature, then lessens it to a trickle. It works the same with our conventional tank here and the tankless one in Italy. (But most of the time, Martin is much more conservation-oriented: He turns on the hot water, puts a stopper in the sink, and fills it with only as much as he needs to shave. No waste there.)

We do have one problem with the tankless heater in Italy. That’s with the water for the shower. It’s on the other side of the apartment from the water heater, and so, you have to turn the shower on and run it for a few minutes for the hot water to travel from kitchen, where the tankless heater is.

But here in the US, we have the same issue with our conventional tank. I also have to leave the shower in the bathroom running a minute or two for the hot water to travel from the basement to the shower upstairs. So is this really a problem unique to tankless heaters?

At Sheep Dog, we’ve decided to go with two Noritz gas-fired tankless heaters – one to be installed in a kitchen closet, the other near the bathrooms. That way we’ll have our hot water sooner than we currently do with the water traveling up from the conventional tank to the kitchen and baths.

And finally, here’s my last complaint about Consumer Reports: Their bottom-line analysis is too limited in its scope. Isn’t it time to adjust our cost-benefit analysis from merely focusing on our individual pocketbooks to including the overall good of the economy and generations to come?

It might take me 20 years to break even when I install my tankless heaters, but during that time I’ll be using 22 percent less of a finite fossil fuel resource each year. Isn’t that worth considering?

In fairness to Consumer Reports, they did have a video clip accompanying their article that after listing all of their perceived cost and inconsistent temperature problems, concludes: “But if saving energy is important to you, getting a tankless water heater may be worth it.” Yup, it might be!

Editor’s note: Alexandra Marks blogs on Tuesdays and Thursdays about her green and budget-friendly restoration of a 1902 farmhouse in Connecticut. Click here to find all her blog posts and articles.

The Monitor's Environment section has a new URL. And there's a new URL for its Bright Green blog. We hope you'll bookmark these and visit often.

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