Tankless Water Heaters

While tankless water heaters have been widely available in the U.S. and Canada since the 1990s, many homeowners may be learning about them for the first time. If you've never owned one, you may be wondering if they're right for you and how they differ from their tanked cousins. While tank and tankless water heaters both get the job done, knowing how they differ might be helpful when deciding if a tankless water heater is right for your home.

How Do Tankless Water Heaters Work?

Tankless water heaters, also known as on-demand water heaters, provide hot water only when you need it. When you turn on a hot water faucet, cold water travels through a pipe into the tankless unit. A powerful heating element within it, either a gas burner or an electric coil, then rapidly heats the water as it passes through.

Advantages and Considerations of Going Tankless

Here is how an on-demand tankless system compares with a traditional tank water heater.

Gas vs. Electric Tankless Water Heaters

Tankless units come in gas and electric models. The right one depends on how much hot water your household uses at once, your existing utilities, and where the unit will be installed.

The Best Way To Size Your Tankless Water Heater

You should not size a tankless water heater by square footage. Instead, it's much better to concern yourself with these two measurements:

• Peak flow rate. Adding up all the plumbing fixtures you are likely to run at the same time allows you to measure their combined hot water demand in gallons per minute. This is called your peak flow rate.
• Temperature rise. The unit has to bring your incoming water up to about 120°F. In winter, water entering the home can be near 40°F, so the unit needs enough capacity to make up that difference on the coldest days.

What Maintenance Is Recommended For Your Tankless Water Heater?

The biggest threat to a tankless unit's lifespan is hard water. Because the system heats water quickly to high temperatures, dissolved calcium and magnesium can crystallize and build up as scale inside the heat exchanger, forcing the unit to work harder and shortening its life. Here are some recommended maintenance items to keep your tankless water heater functioning at its best:

• Treat the water upstream. In hard-water areas, a water conditioner or a whole-home water filtration system reduces minerals before they reach the unit.
• Descale about once a year. Flushing the unit with a descaling solution roughly once a year clears mineral buildup and helps keep the manufacturer warranty valid.

Frequently Asked Questions About Tankless Water Heaters