Whole House Tankless Water Heaters
A. O. Smith has been a leader in whole-house water heating solutions for over 80 years. With the addition of electric tankless and gas tankless whole-house water heaters, A. O. Smith continues to deliver innovative products that are built to last.
Rebates & Tax Credits
*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
- 199,000 BTU input
- 15-Year Warranty
“I love not having to worry about running out of hot water.�?
- Delivers 97-gallon first hour rating
- 50,000 BTU input power vent design delivers up to 0.72 Uniform Energy Factor
- 6-Year Tank & Parts Warranty
“Endless hot water supply has made our entire family happy!�?
- Delivers 97-gallon first hour rating
- 50,000 BTU input power vent design delivers up to 0.72 Uniform Energy Factor
- 6-Year Tank & Parts Warranty
“Great unit! I would recommend it to anyone. Reputable brand�?
Benefits of Tankless Water Heaters
Continuous Hot Water
Tankless water heaters deliver continuous hot water. If sized properly, you’ll never run out of hot water again.
Energy Savings
A. O. Smith tankless water heaters heat your water only when you’re using it, reducing energy costs depending on your hot water usage.
Space Savings
Due to their significantly smaller size, tankless water heaters save a tremendous amount of space compared to a traditional water heater and can be mounted in various spaces around your home.
On-Demand Hot Water
The heating technology within A. O. Smith tankless water heaters provides on-demand hot water by heating the water when you need it.
Instant Hot Water
A. O. Smith tankless water heaters with built-in recirculation pumps offer instant hot water when installed with the proper piping.
Innovation & Reliability
A. O. Smith has a long, rich history of reliability and innovations that have led the water heating industry for decades.
How it Works
Whole-house tankless water heaters produced by A. O. Smith deliver hot water on demand and can help in reducing energy consumption for your home. Built with scale-reduction technology, both electric tankless and gas tankless whole-house water heaters perform with high efficiency and are built to serve a wide range of applications.
A whole-house tankless water heater is built to provide continuous hot water whenever you need it. When a hot water tap is turned on, water from your cold water pipe enters the water heater and passes through the heat exchanger. With an electric tankless product, the water passes over the heating elements, quickly heating the water to your desired temperature. The process is the same for a gas tankless water heater, but instead of heating elements powered by electricity the burner is fueled by a natural gas or liquid propane line. For all A. O. Smith tankless water heaters, a continuous supply of hot water is delivered to your home with ease.
Still Have Questions?
- How much does it cost to install a tankless hot water heater?
The cost of installation can vary depending on the current plumbing of your home. A. O. Smith recommends contacting a licensed contractor to begin the evaluation process. - What size tankless water heater do I need for my house?
After evaluating your desired water supply, your home’s climate and current piping, a licensed contractor will be able to provide an exact recommendation for your home. Use the XPERT™ Product Selector to get an initial recommendation on which water heater would be right for your home. - Where should I install a tankless water heater?
Electric tankless water heaters can be installed in any location within your home with the appropriate hookups. Their compact size frees up valuable space within your home. For gas tankless water heaters you will need to utilize specific venting, which will impact where you can install throughout your home. - How do you vent a tankless water heater?
No venting is required for A. O. Smith whole-house electric tankless water heaters, but for gas tankless water heaters you will need to consult with your local plumbing contractor to determine the best venting for your home.
Whole House Gas Tank vs. Whole House Gas Tankless
Take a closer look at the advantages of each type of water heater.
Whole House Gas Tank Water Heaters
- Low initial investment
- Energy-efficient options
- Easy installation
- Wide range of tank sizes from 30 to 95 gallons
- Hot water storage supply
Whole House Gas Tankless Water Heaters
- Continuous hot water
- Energy efficient
- Space savings
- Environmentally friendly
- X3® Scale Prevention Technology on select models
Find A Local Water Heater Pro
A. O. Smith water heaters are professionally installed by local independent contractors.
Featured Whole House Tankless Water Heaters
- Delivers 97-gallon first hour rating
- 50,000 BTU input power vent design delivers up to 0.72 Uniform Energy Factor
- 6-Year Tank & Parts Warranty
- 199,000 BTU input
- 15-Year Warranty
- 199,000 BTU input
- 15-Year Warranty
- 240V
- 22 kW
- 5-Year Warranty
High-Efficiency Condensing Gas Tankless Water Heaters
Learn more about A. O. Smith’s full line of high-efficiency condensing gas tankless water heaters.
Non-Condensing Gas Tankless Water Heaters
Learn more about A. O. Smith’s full line of non-condensing gas tankless water heaters.
Electric Tankless Water Heaters
Learn more about A. O. Smith’s full line of Electric tankless water heaters.
Not sure which product is right for you?
Interested in Learning More?
Why A. O. Smith?
A. O. Smith is a leading manufacturer of both residential and commercial water heating technologies, including the #1 most specified commercial water heater.
For more than 145 years, we’ve developed state-of-the art products that push new boundaries and improve the lives of our customers.
We combine cutting-edge technology with committed people who take pride in providing the very best support for our customers.
Our products are put through rigorous quality and endurance testing so no matter where hot water is needed, A. O. Smith can provide a solution you can count on.
Frequently Asked Questions
Yes, A. O. Smith manufactures whole-house electric tankless water heaters that provide continuous hot water on demand. These units require no venting since they don't produce combustion gases, making them flexible for indoor installation. Electric tankless models come with a 5-year limited warranty and typically deliver 2-5 gallons per minute. While they have lower flow rates compared to gas models, they work well for whole-house needs when properly sized and are ideal for homes without gas service or with limited installation space.
Electric tankless water heaters have lower flow rates (2-5 gallons per minute) compared to gas models and require dedicated electrical circuits that may need rewiring. They also have shorter warranties (5 years vs. 15 years for gas) and higher upfront installation costs. Colder climates may need more powerful units with higher energy draws. However, electric models offer no venting requirements, flexible installation locations, energy savings from on-demand heating, and space-saving designs that work well for homes without gas service.
Yes, a tankless water heater can run a whole house when properly sized for your household's hot water needs. Sizing depends on your peak flow rate in gallons per minute based on simultaneous fixture use. Gas tankless models deliver 5-10 gallons per minute, while electric models provide 2-5 gallons per minute. Most units accommodate two to three people showering simultaneously. Calculate your maximum usage by adding fixtures used at once (showers at 2.5 GPM, faucets at 0.75 GPM, dishwasher at 1.5 GPM). Climate also affects sizing since colder incoming water requires more heating capacity. Use A. O. Smith's XPERT Residential Water Heater Selector for accurate sizing recommendations.
Size depends on your peak hot water flow rate in gallons per minute. Calculate simultaneous usage by adding fixtures used at once (showers at 2.5 GPM, faucets at 0.75 GPM, dishwasher at 1.5 GPM). A typical household needs 5-10 GPM for whole-house coverage. Gas tankless models provide 5-10 GPM, while electric models deliver 2-5 GPM. Climate matters since colder incoming water requires more capacity. Use A. O. Smith's XPERT Residential Water Heater Selector for personalized recommendations based on your household size and local climate.