Combi Boiler Water Heating & Space Heating
For over 80 years A. O. Smith has been a leader in the water heating industry, A. O. Smith provides energy efficient solutions for water heating needs, including combination boiler water heaters that also provide space heating.
What Our Customers Are Saying
- ENERGY STAR® Certified
- 150,000 BTU input
- 10-Year Warranty
“I love this unit. We had an old…Boiler installed and our home was the last to replace it and wished we had done it earlier. Efficient, Quiet, Endless Hot water. So far so good…�?
- ENERGY STAR® Certified
- 150,000 BTU input
- 10-Year Warranty
“...Installation went without any issues. Thank you!�?
Benefits of Combi Boilers
All-in-One Water & Space Heating
Our high efficiency 95% AFUE combi boilers can replace both a water heater and space heater in your home to save you space, improve performance, and help you save money on operating costs.
Reliable Hot Water Supply
The ProLine® XE Combi Boiler provides industry-leading continuous hot water delivery with its on-demand, high efficiency design.
Superior Space Heating Performance
The ProLine® XE Combi Boiler offers up to 74% more heating capacity than other combination boilers.
Space Savings
Easy to install and maintain, combi boilers feature a compact footprint and a wall-hung design that frees up space in your home.
Money Savings
A. O. Smith combi boilers have a 95% AFUE (Annual Fuel Utilization Efficiency) and are ENERGY STAR® certified, which helps you save money on your energy bills.
Easy Installation
Direct venting options up to 100 feet allow for flexibility and easy installation.
How it Works
Combination, or Combi, boilers provide high efficiency space heating and domestic hot water (DHW) in a compact footprint that is easy to install and maintain. When a hot water tap is opened, incoming water flows through the heat exchanger. Heated boiler water, supplied from the fire tube heat exchanger, prioritizes heating the domestic water to the desired temperature. When space heating is needed, a diverter valve directs the heated boiler water into the external space heating loop.
Still Have Questions?
Combi boilers are designed to accomplish both space and water heating with a single appliance. Like a tankless water heater, a combi boiler provides hot water on demand. It can also seamlessly switch between water heating and space heating to provide the best possible experience.
Find A Local Water Heater Pro
A. O. Smith water heaters are professionally installed by local independent contractors.
Featured Combi Boilers
- ENERGY STAR® Certified
- 199,000 BTU input
- 10-Year Warranty
- ENERGY STAR® Certified
- 150,000 BTU input
- 10-Year Warranty
- ENERGY STAR® Certified
- 110,000 BTU input
- 10-Year Warranty
Not sure which water heater is right for you?
Take our water heater selector quiz to find the correct water heater for your home.
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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 now matter where hot water is needed, A. O. Smith can provide a solution you can count on.