Discover the best products for home water heating - condensing water heaters - including both conventional storage tank and tankless models.
Learn how selected condensing models provide ultra-efficient water heating, resulting in savings of over 50%, a high energy factor of up to 0.97, and Energy Star compliance for additional incentives.
Compare top brands such as Rinnai, Noritz, Navien, AO Smith Vertex, and Polaris to find the perfect fit for your home.
Read further to make an informed decision!
Residential gas-powered condensing water heaters, also known as condensing boilers, combi boilers, and cylinders, have long been popular in Europe, where combi boilers are found in nearly 70% of homes in the UK. In North America, they have been widely used for commercial applications, but rising gas prices and lower operating costs have made them increasingly popular for residential water heating.
In addition, government legislation and higher demand for energy-efficient water heating systems have made condensing heaters a favorable gas type. These units use advanced technology to extract more heat from the combustion process, resulting in significantly higher efficiency ratings compared to traditional water heaters. With both tankless and tank-type options available, condensing water heaters can provide a reliable supply of hot water while reducing energy bills and carbon emissions.
Condensing water heaters with a tankless design have two heat exchangers, typically made of stainless steel, which makes them unique. Water passes through the primary heat exchanger where it is heated on-demand without the need for storing.
The secondary heat exchanger captures the heat energy from flue gases and preheats the incoming cold water, boosting efficiency to over 90%. This feature allows homeowners to save money on energy bills while enjoying a continuous supply of hot water.
Rinnai, Noritz, and Navien are some of the popular brands that offer the best condensing and tankless water heaters on the market. These units provide reliable and energy-efficient solutions for residential water heating.
The Rinnai RUR98i is an indoor water heater that is considered the best from the manufacturer. This powerful unit, available on Amazon, has a water flow rate of 9.8 GPM and an efficiency rating of 0.95, making it ideal for demanding families.
The exclusive ThermaCirc360 feature allows the unit to be used in recirculation, delivering hot water fast and reducing energy waste, wait time, and increasing comfort. Advanced electronics and an eco-friendly gas burner, combined with the modulating gas valve, allow this unit to operate efficiently and generate ultra-low NOx gas emissions.
With a warranty of 12 years, the Rinnai RUR98i is a reliable and efficient choice for residential water heating needs.
The best of Noritz is a direct vent model NRCP1112 built for indoor installations only.
NRCP1112 is a condensing water heater that produces a high hot water flow of 11.1 GPM, making it great for large homes with up to 4-5 baths and an energy factor of over 0.9, providing savings over 50%.
Noritz NRCP1112 is equipped with an internal circulation pump with two modes to reduce the wait time for hot water while saving water and energy. The advanced electronics and large control panel interface allow users to take advantage of the heater's programming and diagnostic system to control, monitor and troubleshoot if there is a problem with the water heater.
The water heaters come with a 12-year warranty.
Navien NPE-240A is a premium condensing water heater from this Korean manufacturer, designed to provide an endless supply of hot water. It's one of the largest models available, capable of delivering a high flow rate of 11.2 GPM and an impressive efficiency rating of 0.97. The unit can also be used in a cascade system for high-demand applications, with multiple units connected and operated by a single controller.
Navien NPE-240A features ComfortFlow Technology, which eliminates water temperature fluctuations and cold water sandwiches. The built-in recirculation system ensures faster hot water delivery, while the Intelligent Preheating Technology recognizes usage patterns to increase comfort and overall satisfaction.
This water heater is built to last and comes with a warranty of 15 years, making it a reliable and long-lasting choice for your home.
Video: AO Smith Vertex
Unlike tankless models, tank-type condensing water heaters have a single high-performing helical heat exchanger surrounded by water. Excellent examples are AO Smith Vertex and American Polaris (available on Amazon), both utilizing a fully condensing design that ensures an impressive thermal efficiency of 96%, rivaling much larger heaters.
The Polaris condensing water heater is lighter, more powerful (199,000 BTU vs. 100,000 BTU), has a much higher recovery rate (253 vs. 129 gallons), and a longer warranty (10 years vs. 6 years for the Vertex), but it also costs more for a 50-gallon size comparison.
The combustion gases travel through the flue spirals around and inside the tank, increasing heat transfer and causing water vapor in the gas, a natural by-product of the combustion process, to condense and release even more energy. The exit point of the flue is barely warm to the touch.
Another quality component is the metal fiber burner, which is highly resistant to stress and corrosive water effects. It is located in the sealed combustion chamber, generating a very clean and high-intensity blue flame, resulting in less pollution and intensive heat transfer.
Condensing water heaters are gas-fired units that operate similarly to conventional models. However, these conventional heating systems, which are the most popular in America and Canada have a major drawback: they waste a lot of heat energy when flue gases are vented out.
Fortunately, condensing and energy-efficient water heaters offer a smart solution by recapturing the heat of the flue gases and using it to preheat the incoming cold water. This approach reduces the amount of wasted heat energy, resulting in ultra-high efficiency and lower venting costs.
To achieve such efficiency, condensing boilers require larger and more efficient heat exchangers than traditional boilers, along with other improvements.
One key advantage of condensing boilers is that the water vapor produced by burning gas in the boiler condenses back into liquid water, releasing the latent heat of vaporization. This latent heat is a significant source of energy that condensing boilers can recover, resulting in efficiency ratings of up to 98%.
When buying a water heater, there are several things to consider to ensure you get the best one for your needs. Here are some tips:
Condensing water heaters are ideal for homeowners who prioritize energy efficiency, environmental impact, and long-term cost savings. They are particularly suitable for households with high hot water demand, as they provide a consistent supply of hot water without wasting excess energy.
However, due to their higher upfront cost and more complicated installation, they may not be the best choice for everyone. Those who plan to stay in their homes for an extended period and are willing to make an investment in a more efficient and eco-friendly water heater may find condensing models to be a worthwhile purchase.
A non-condensing water heater is a traditional type of water heater that operates by burning fuel (gas or propane) to heat the water in a tank. The flue gases produced during combustion are vented out of the house through a chimney or other exhaust system, without recapturing any of the heat they contain. These types of heaters have a lower thermal efficiency compared to condensing water heaters, meaning they waste more energy during operation.
Yes, a condensing tankless water heater typically requires a drain. This is because condensing models produce condensate, which is acidic and needs to be drained properly to prevent damage to the unit and surrounding area. The drain line should be installed according to the manufacturer's instructions and local building codes to ensure proper drainage and safety.