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High-Efficiency Condensing and Non-Condensing Gas Tankless Water Heaters

In 2010, A. O. Smith introduced its full line of natural gas and propane tankless water heaters that continue to be an innovative part of the full A. O. Smith product family today. Engineered to deliver continuous hot water when you need it, propane and natural gas tankless water heaters are easily installed in tight spaces, including closets, bathrooms and even outdoors in appropriate climates.

Non-Condensing Gas Tankless Water Heaters

Residential Non-Condensing Gas Tankless Water Heaters

A. O. Smith’s non-condensing gas and propane tankless water heaters provide endless hot water for your home. All non-condensing tankless water heaters from A. O. Smith offer a water heating solution that is built to last.

Water Heater Rebates & Tax Credits

Up to $850 in Local Utility Rebates may be available in your area!

*Gas water heaters with UEF of 0.82 or higher OR with a thermal efficiency of at least 90%. Local utility rebates available in limited geographical areas. For information on the Federal Tax Credit, go to: energystar.gov. Check with your tax advisor for applicability. Offer details and expiration may vary. See Rebate Center for details.

What Our Customers Are Saying

Benefits of Non-Condensing Gas Tankless Water Heaters

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Continuous Hot Water

Non-condensing tankless water heaters produce continuous, on-demand hot water for your home and can provide instant hot water through the installation of an accessory hot water recirculation pump.

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Space Savings

A. O. Smith’s non-condensing tankless water heaters can be mounted in small or tight spaces, either inside or outside of your home, to better utilize and save space.

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Energy Savings

Non-condensing tankless water heaters vent away the excess heat produced during the heat exchange process, causing less corrosion and deterioration of the water heater and resulting in a longer life span.

How it Works

non-condensing gas tankless water heaters

An A. O. Smith non-condensing tankless water heater saves space and supplies continuous hot water for your home. Non-condensing technology utilizes a single heat exchanger to heat the water to the desired temperature. Water flows through a heat exchanger where it is heated to the desired temperature by the hot exhaust gasses. The excess heat that is not transferred to the water is expelled through the exhaust venting. This exhaust is higher temperature than on a condensing tankless heater to lessen the risk of corrosion. However, non-condensing heaters generally require metal exhaust venting to withstand the higher temperatures. Paired with a 15-year limited warranty, an A. O. Smith non-condensing tankless water heater can provide years of hot water for your home.

Still Have Questions?

A non-condensing tankless water heater is a compact water heater without a tank. It heats water only when demanded by appliances and hot water faucets. Cold water passes through a heat exchanger, which heats it to the desired temperature by hot exhaust gasses. It then releases unused heat through ventilation. By comparison, a condensing tankless water heater has two heat exchangers. The second one improves energy efficiency by capturing and recycling unused heat instead of venting it right away. Learn about high efficiency condensing tankless.

Condensing tankless heaters use a dual heat exchanger design to make maximum use of the energy delivered to the system. Non-condensing tankless water heaters utilize a single heat exchanger so they vent more heat in the exhaust gasses.
A professional contractor can help you choose the best non-condensing tankless water heater for your home's water needs and recommend installation and venting setup. They'll consider the piping in your residence, the demand on the water supply for appliances and personal use, and the temperature of the water coming into your home. Your contractor can also recommend where to place the tankless water heater. Because these models are compact, they can be installed in various locations, such as a closet or garage, depending on the home's plumbing configuration. You can also install water heaters outside in warmer climates.

How do I keep my tankless water heater from freezing?
All A. O. Smith tankless hot water heaters have built-in freeze protection. However, if the heater is installed outdoors, during a power outage you will need to drain the water from the unit to prevent freezing.

Does a non-condensing tankless water heater require a drip pan?
Use a drip pan with your tankless water heater as a precaution. This protects your home from water damage and mold should the water heater leak. Because tankless models don't have storage tanks, a drain pan should be enough to contain any leakage.

The proper size of a tankless water heater depends on a number of variables, including type of appliances you own, number of people in your home, and incoming water temperature. You should discuss with your installer, but you can also consult our online XPERT™ Product Selector that can also be found as a downloadable app.
Yes, you can install tankless water heaters outside in warmer climates where there's no risk of freezing. This helps free up space inside the home. These water heaters are easy to install and have built-in vents, eliminating the need for venting through the wall of a house. A. O. Smith tankless water heaters have internal freeze-protection to withstand the cold when temperatures drop, but you should drain them if there's a power failure to prevent freezing.

Product Comparison

Adapt XE
Standard Non-Condensing Gas Tankless Water Heater
Adapt XE Premium Condensing Gas Tankless Water Heater with X3® Technology
Standard Non-Condensing Gas Tankless Water Heater
Adapt Premium Condensing Gas Tankless Water Heater
Single Shower Length
Showers Back-to-Back
Showers at the Same Time
2.6 showers
3.1 showers
Maximum Tub Size
X3® Scale Prevention Technology
Continuous Hot Water
Space Savings
Energy Efficiency
Hot Water Storage Supply
15 Years
15 Years

*Many factors affect the actual performance of a water heater. This represents our closest approximation of your likely experience with this water heater in your local area, but actual performance may vary depending on factors beyond our ability to control or estimate.

Plumbing Professional

Get it installed by a Local Pro

A. O. Smith water heaters are available through your local plumbing professional.

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Why A. O. Smith?

Market Leader

A. O. Smith is a leading manufacturer of both residential and commercial water heating technologies, including the #1 most specified commercial water heater.

Commitment to Innovation

For more than 145 years, we’ve developed state-of-the art products that push new boundaries and improve the lives of our customers.

Best-In-Class Support

We combine cutting-edge technology with committed people who take pride in providing the very best support for our customers.

Unmatched Quality

Our products are put through rigorous quality and endurance testing so now matter where hot water is needed, A. O. Smith can provide a solution you can count on.

Learn more about A. O. Smith