We often take for granted the fact that heating up water — for use in sinks, showers, dishwashers and elsewhere — accounts for an estimated 30 percent of an average home’s energy consumption. Add in concern over carbon dioxide emissions by gas-powered water heaters and you begin to understand why budget- and eco-conscious homeowners have begun to question whether it’s time to go tankless.

What is a tankless water heater?

A traditional boiler, whether gas or electric, continuously heats a volume of water within a storage tank all day and night, every day and week throughout the year.

There’s a logical disconnect here, isn’t there? Why would you pay to heat water even when you’re asleep or away from home, and especially when that water is being heated by burning fossil fuel?

Tankless water heaters, on the other hand, only heat up water when there’s demand for it. Those who have traveled in Europe may already be familiar with tankless systems, especially “point of use” setups.

Of course, the technology has improved and now manufacturers claim that whole-house heaters of adequate size can provide a steady flow of water at a set temperature to multiple fixtures at once. But instead of storing water and actively heating it, tankless models only switch on when there is water moving through the unit on its way to the source, be it a shower head or laundry machine.

More Cost Upfront, Cheaper To Run

A tankless gas water heater takes up a lot less space.

Because they require less energy to run, tankless heaters are significantly cheaper to operate. Although upfront costs can be high (for the unit itself plus installation), payback arrives over the long term, usually after a few years, with homeowners saving 24–34 percent annually, according to the Air Conditioning, Heating, and Refrigeration Institute.

Another reason to like tankless water heaters is the units’ compactness. They can be mounted on a wall, tucked under stairs, or placed inside a closet, making them appropriate for a range of applications.

A large family house with lots of kids may require two units to produce enough hot water to meet demand, but operating within capacity, a tankless heater should be able to provide unlimited hot water — a relief to anyone used to running out mid-shower. Plus, leaks are much less likely with a tankless, because, well, there’s no tank.

Is it time to go tankless?

An increasing number of homeowners around the country have already made the switch. This year, when my wife and I needed to replace the boiler at our home in Florida, we asked, “Is it time to go tankless?”

We assessed our options and answered “Yes.”

“Time to Go Tankless? The Pros and Cons of Tankless Water Heaters” was originally run as “Time for Tankelss? The Next Generation of Boilers” and was written by Bob Vila for Zillow.com.