With numerous benefits such as compact sizing, high-efficiency operation and cost effectiveness, it’s easy to understand why the combi-boiler market is growing. According to a study released earlier this year by Global Market Insights, the combi-boiler market is expected to exceed $30 billion by 2026


An energy efficient, space-saving option

According to Andrew Tran, marketing manager for Noritz, interest in the combi-boiler market has been growing over the past couple of years. 

“We’re seeing more millennial homebuyers start to remodel or renovate their homes,” he notes. “And just like tankless water heaters, efficiency and space savings are a big deal with combination boilers. If you're replacing old boilers, you want them to be more energy-efficient and work better than what you had, especially with the savvier and younger consumers.”

Tran notes that local and state level rebates have helped drive interest in the products.

“We’ve even seen some regions where the local rebates cover the cost of the boiler, and that’s really exciting to see,” he says.

Brea Figura, tankless marketing manager for Rheem Mfg. Co., agrees with Tran’s assessment that rebates are helping drive the market forward, as are government regulations pushing for higher efficiency products.

“Over the last four years, combi-boiler sales have grown at an exponential rate as people experience the products,” she says. “When you have the ability to provide space heating and endless domestic hot water, it’s a win-win. Rebates play a significant role in combi-boiler installations as they offer some of the largest rebates available for residential products in the respective markets where boilers are sold. Education and training has also played a huge role in the success of combi-boilers within the market, like with all high-efficiency appliances.”

The efficiency is a large decision-making factor when selecting these products, she notes.

“In many cases, we see non-condensing boilers being replaced with condensing combi-boilers,” Figura says. “In most applications, the original non-condensing boiler was very oversized and non-modulating. These two items are large factors in the actual energy dollar savings a consumer may see. While the efficacy difference may only be 10% in favor of the condensing combi, the net utility bill savings may be close to 30%. This has a lot to do with the modulation and turndown ratio that modulating condensing boilers provide.”

Many heating markets still have boilers installed with gas powered tanks or indirect tanks, Figura notes. These are the applications that are primed for combi-boiler replacements.

“The best applications are in areas where you can eliminate a gas water or indirect tank,” Figura says. “The compact nature of a combi-boiler lends itself to significant space savings. Additionally, when it comes to new construction, we see a growing need and demand in multifamily applications where space heating is done with boilers. In these applications, we are able to save space and reduce the amount of gas lines that need to be ran, as now you only need to connect one appliance to the utilities. The project cost savings is gigantic when you consider projects with more than 200 units. Essentially, you are reducing the need to run multiple gas lines per unit.”

John Kopf, product manager — boilers at Navien, notes combi-boilers have been trending in multifamily dwellings, where space is at a premium.

“A combi-boiler offers a perfect solution for these applications because it condenses space heating and domestic hot water appliances into a single unit,” he explains. “Not only does it save mechanical room space, but it also eliminates the need for the separate venting, gas lines and electrical connections. 

“Most of new technology in combi-boilers comes from Europe where a typical home or apartment is much smaller than in North America,” Kopf adds. “The small amount of available space favors compact systems that combine space and domestic heat into a single unit. Long-term maintenance and operating costs are also reduced when dealing with a single unit versus to separate appliances.”

Advanced controls

Mike Boyd, product manager at Weil-McLain, explains a large trend in the combi-boiler market is better control functionality than previous generations.

“Some earlier combi versions in the market had to add components to help mitigate the occurrence of domestic hot water temperature swings,” he says. “For example, the Unity 2 control on the Weil-McLain ECO Tec boilers have embedded advanced domestic hot water algorithms in the combi versions help ensure homeowner comfort with no callbacks.”

Kopf agrees, saying combi-boilers have seen improvements in controls and on-board Wi-Fi remote access.

“More advanced controls really started taking off recently, and they include startup wizards, more intuitive front panel displays featuring touch screens, improved recirculation methods and built-in zone controls,” Kopf says. “Remote access to change unit operating parameters, perform diagnostics and troubleshooting has quickly become an expected feature. Improvements in product warranties are another industry trend, especially seen in manufacturers who use automated production and are confident in high quality of their products.”

According to Kopf, it is the highly competitive nature of the market that is driving new developments in controls and increased connectivity.

“Customers are becoming more technology savvy and expect products that come with advanced controls allowing them to access their equipment remotely,” he says. “Continuous advancements in technology enabled boiler manufacturers to take advantage of these market demands and deliver new products that are highly innovative but easy to use.”



Manufacturer: Navien
Product: NFC Series fire tube combi-boilers
Description: Navien NFC fire tube combi-boilers are available in 175,000 Btu/h and 199,900 Btu/h models, both offering 95% AFUE and 11:1 turndown ratio. Each model comes with a patented in-house designed and manufactured heat exchanger, advanced controls and a built-in DHW module with mixing valve, water adjustment valve and auto water fill valve.
For more information: www.navieninc.com


Manufacturer: Noritz 
Product: CB Combination Boiler
Description: The CB Combination (Combi) Boiler utilizes high-efficiency condensing technology to deliver hot water to both plumbing and hydronic heating applications. The unit delivers hot water at a 95% efficiency, earning it the highest ENERGY STAR rating, the company says. Delivering up to 9.2 gpm of domestic hot water, the product can be used on a whole host of applications, including radiator, baseboard or in-floor radiant hydronic heating. It can also be used in HVAC systems using water-to-air heat exchange with an air handler and pavement snow melting.
For more information: www.noritz.com


Manufacturer: Rheem Mfg. Co. 
Product: Professional Prestige combination boiler
Description: The Professional Prestige combination boiler from Rheem is a leading innovation among Rheem’s high-efficiency product portfolio, the company says. At 95% AFUE, the boiler is ENERGY STAR-certified and more than 15% more efficient than standard boilers, Rheem notes. The combi-boiler’s compact design is ideal for smaller homes or multifamily applications.
For more information: www.rheem.com


Manufacturer: Weil-McLain 
Product: ECO Tec high-efficiency gas boiler
Description: The new 95% AFUE ECO Tec boiler from Weil-McLain is available in both heat-only and combi versions, and satisfies all residential space and domestic hot water heating needs. It features a durable stainless steel fire tube heat exchanger with sound dampening air silencer for whisper quiet operation, and a corrosion resistant condensate collector base.
For more information: www.weil-mclain.com