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Do Your Homework Before Going Tankless

You’re probably familiar with a standard electric water heater.

It’s basically a large water tank with a couple of heating elements built in to keep the water inside hot. Whenever you open a hot water faucet, the water heater supplies your request.

But is there a way not to have all that hot water sitting around when you don’t need it? A way to heat water only when it’s needed?

Yes, tankless water heaters can do that. And they might seem like a good idea on the surface, but there are a few things you ought to know first.

illustration of tankless water heaterTankless Water Heaters are Expensive

Tankless electric water heaters cost more than a comparable tank water heater. In addition, the electrical wiring to connect the unit may cost more than the tankless water heater itself.

“Tankless water heaters require huge amounts of power at one time,” says Tim Morris, Walton EMC vice president of engineering and operations. “That’s because they’re trying to raise the temperature of 65-degree ground water to 120 degrees or more in an instant.”

That translates to a big wire feeding the tankless water heater. It’s a trickle-down effect. The large wire requires a larger branch circuit breaker in your electrical panel. That means the electric panel, its main breaker, the service entrance wire and/or transformer has to be beefed up. It adds up quickly.

“And if you’re talking about an existing home where the electrician has to tear out the old electrical system and then install the upgraded wiring, it’s even more expensive,” says Morris.

According to Consumer Reports, the time to recoup your investment can be longer than the tankless water heater’s warranty. “If you have a warranty of 12 to 15 years, which is typical, it doesn’t make financial sense to replace a tank water heater with a tankless,” said a plumber interviewed by the publication.

All this could possibly affect the charge you incur for underground electric service in a new home.

Tankless Water Heaters have Limited Hot Water Capacity

Two people want to take a shower at once? They may be out of luck.

With tankless water heaters, every time another hot water faucet is opened, the temperature of the water at every faucet goes down. What if the washing machine is running too? Uh-oh.

With a heat-as-you-go system, there is only so much hot water the unit can supply in an instant. On the other hand, standard water heaters have a large reserve – or in other words, a buffer – they can use to meet the demand of several users at once.

One tankless manufacturer’s product literature lists the maximum number of showers at once as 1.7. That means somebody is in for a cool shower.

Tankless Water Heaters may not be Future Proof

The power used at once – called electrical demand – of tankless water heaters is off the chart.

For comparison, the demand of the average central air conditioner or standard water heater is around 5 kilowatts. The demand of an electric oven is 8 kilowatts. The demand of a tankless water heater can be as much as 36 kilowatts, or more than four times that of an oven!

In the future, utilities may change residential rate structures to take electrical demand into account when calculating your bill. If you have a tankless electric water heater, watch out!

The wise choice for electric home water heating continues to be the traditional tanked water heater. Quiet, economical and easy to install, the tanked electric water heater is a proven solution for today’s homeowner.