The drive for higher-efficiency boilers, decarbonization and electrification are the major forces hydronics manufacturers are keeping their eyes on this year, according to research we conducted for our 2024 Boiler Report.

“Boilers are being targeted heavily by federal regulators,” says Jim French, vice president of sales, boilers and specialty products, Bradford White Corp. “Most prominently, the federal government is prepared to release a final rule later this year to increase the minimum-allowed [Annual Fuel Utilization Efficiency] AFUE for residential boilers, which will undoubtedly influence product designs.”

Federal standards, proposed last year, would call for these products to use only condensing technology.

“It would represent changes not only to product design,” he adds, “but likely system design in the field, especially as it relates to unit replacement in existing construction.”

Manufacturers shared other regulations and mandates, big and small, federal or local, that impact what they make and bring to the hydronics market.

To understand what’s happening in the hydronics market, we sent out questionnaires to the following manufacturers: AERCO (a Watts brand); Bosch Home Comfort; Bradford White Corp.; ECR International; HTP/Ariston Group; IBC Technologies USA (a Rheem company); Laars Heating Systems; Lochinvar; Navien; NextGen Boiler; NTI/Ariston Group; Rinnai; Thermal Solutions; U.S. Boiler Co.; and Weil-McLain.

Decarbonization Trend

“The push toward electrification and the elimination of natural gas hooks in some states require us to look at alternatives in the way we deliver hydronic heat,” notes David Walsh, director of business development, HTP. “Being part of the Ariston Group gives us access to a vast array of products currently being used in other countries that we could ‘Americanize.’”

We’ve been publishing these annual reports for many years now, and much of this main feature includes answers to our first two questions:

What current regulatory mandates will impact the design of your products in the next 18 months? 

What boiler trends do you see in different parts of the United States?

“Most of the federal, state and local regulatory mandates in effect are designed to promote the transition to electric space and water heating within the next decade — and the use of ultra-high efficiency gas boilers to reduce emissions during this transition period,” says Ross Brawner, product manager, Lochinvar.

Brawner notes that the state of Washington, for example, now requires the installation of heat pump water heaters and electric boilers in most new commercial buildings to eliminate the use of fossil fuels. And in Washington, D.C., gas boilers will be phased out by the end of 2026 in new buildings, tightening restrictions on the city’s greenhouse gas emissions. 

Meanwhile, Chicago is considering an attempt to ban natural gas in new construction, large additions and major renovation projects. 

“Overall, nearly 150 jurisdictions have put forth decarbonization efforts that affect the design and development of new technology,” Brawner explains. 

Although David Hoskyn, director of product management, Navien, believes his company’s products are already highly efficient, his company continues to focus on “lowering emissions, including being low-NOx certified.” 

Coming regulations, however, “most likely will lower what is allowed in some areas,” he adds.

“Some of the changes that may be coming are Energy Star’s proposed ‘sunsetting’ of gas boilers as a listed category,” Hoskyn explains. “To replace those very efficient boilers, the Department of Energy is working on a rating for air-to-water heat pumps. They are very efficient, but have some significant design and application challenges, especially in colder climates where boilers are used.”

Along with the DOE initiative, Hoskyn adds that the Air-Conditioning, Heating and Refrigeration Institute is currently working toward a certification process for air-to-water heat pumps that “may be similar, but needs to be monitored.”

Finally, Hoskyn indicates other changes upcoming at the state level, including “lower allowable NOx emissions in certain states, with a full ban in California air districts.” 

Regarding these two questions, we heard plenty of responses related to sustainability as many manufacturers with traditional heritages in the fossil-fueled equipment adapt to a new “greener” market.

“Today’s ultra-high efficiency gas boilers play a vital role in transitioning to an all-electric future,” Brawner explains. “They have a much lower carbon footprint than previous copper-tube/cast-iron gas boilers that generally provided only mid-range efficiency.”

Chuck O’Donnell, director of marketing, Laars Heating Systems, indicates strong growth in his company’s residential and commercial condensing boiler products.

“There is also heightened interest in our electric boiler offerings, especially in localities where lower electric rates exist due to a large percentage of renewable electricity,” he adds. “We expect growth to continue for high-efficiency, gas-fired boilers and electric heating equipment over the coming years. It is our view that highly efficient combustion equipment and electric-based heating appliances will be needed to heat our homes and businesses for years to come.”

Rahul Goyal, senior director of product innovation and management, Rinnai, says condensing boilers have been gaining market share at the expense of noncondensing boilers.

“Due to recent and upcoming regulations, this trend is expected to accelerate,” he adds.

Mike Senk, product specialist, IBC Technologies USA, says his company recognizes that “product innovation and continually finding new ways to better use the world’s dwindling energy resources is essential to our future success.”

Regulations designed to decrease greenhouse gas emissions drive IBC’s development of “more earth-friendly heating solutions including air-to-water heat pumps and electric boilers. The demand for these zero-emission heating appliances will only increase as more areas ban the installation of natural gas in new construction and move toward electrification.”

On that note, we certainly did hear a lot about heat pumps in last year’s boiler report but much more about electric boilers in this year’s report. It’s certainly great news to Todd Seed, principal of NextGen Boiler.

“As we see governments legislating to remove fossil fuels, NextGen has felt the need to develop a boiler that reaches 185 F,” he adds. “By doing this, we can help our customers solve the current problem of replacement in the ‘above surface’ hydronic market. Additionally, the need for a larger kilowatt boiler is being seen, hence the reason for our start into developing a boiler to reach more than 80,000 BTU.”

Depending on which region of the United States, Seed notes that customers ask his company for an electric combi unit.

“Domestic hot water is something that is being asked for in a few different levels,” he explains. “Customers in rural areas would like to install one unit and accomplish both needs. Customers in urban areas tend to ask for combi’s because of the space constraints.”

While it’s still on the drawing board for NextGen, Seed reports that his company is “working with current manufacturers of air-to-water heat pumps as a solution to boost their efficiencies and provide backup in cold environments. This is working well.”

While NextGen specializes in electric products, as we’ve heard already, other manufacturers with fossil-fuel heritages plan on marketing electric boilers and heat pumps into the mix with efficient boilers.

“Gas bans and emission reduction mandates have already got boiler manufacturers looking for new technologies to meet the requirements of the mandates,” notes Dan Rettig, product manager, Thermal Solutions. 

“Electric boilers are not a new technology, but there has been a renewed interest in them to meet emission requirements,” Rettig adds. “Several new electric boilers have been introduced into the market over the last 12 months and we expect to see many more in the next 18 months. One of the new technologies being introduced into the hydronic market is air-to-water heat pumps. These mandates definitely impact what the Thermal Solutions product portfolio looks like in the coming years.”

Hybrid Approach

“Electric boilers will dominate the conversation beyond what can be attributed to current or future regulations,” says Christian Zapata, product manager, AERCO. “Yet, there’s an understanding that decarbonization doesn’t exclude gas-fired boilers.”

He adds that many factors at “the macro level” determine the optimal boiler solution, such as utility costs, grid management, financial resources and building-specific constraints. And as more buildings feature high-efficiency boilers, Zapata says facility owners and managers ask how they can maximize their investment in efficient boilers.

“One way is to optimize plant application with dual returns and indirect water heating,” Zapata explains. “We’ve seen a significant increase in sales of combination plants across all regions.”

Bottom line: “Gas and electric boilers have a role to play in decarbonizing our buildings,” he says.

And there’s also a place for cast-iron products, notes David DeVries, director of product management, Weil-McLain. 

“In many areas, we have seen the continued shift to high-efficiency residential products for applications that can match and take advantage of the technology,” DeVries explains. “However, there also continues to be a compelling need for standard-efficiency cast-iron products where economics, the existing distribution system designs (emitters and required temperatures) and venting constraints provide a better solution.”

For commercial systems seeking to optimize comfort and efficiency for high-temperature replacement applications, DeVries indicates that the hybrid boiler strategy continues to gain popularity as the industry recognizes the design benefits for building owners.

“Hybrid applications use a commercial noncondensing boiler for lead operation in the core heating season months, and a condensing boiler design for lead operation during the other months,” he explains.

Water and steam boiler trends are characterized by a shift toward greater energy efficiency and sustainability, says Chris Decato, product manager, U.S. Boiler Co., along with a “notable trend” toward incorporating smart technology for remote monitoring and control.

“Geographically, regions with colder climates are witnessing an increased demand for high-performance boilers capable of reliable operation in extreme conditions,” he explains. “Dual-fuel systems that integrate seamlessly with fossil-fuel or electric sources are gaining traction in areas facing temperature extremes.”

He adds: “Government incentives and rebates for energy-efficient heating systems influence trends across the country, encouraging the adoption of advanced technologies. Overall, the industry is aligning with a broader national push toward sustainable and technologically advanced heating solutions.”

For residential customers relying on fuel oil for their heating needs, Weil-McLain has certified its entire line of residential water and steam oil boilers (Ultra Oil, WGO, WTGO and SGO) for use with B20 biodiesel.

“The use of B20 is better for the environment by reducing gas emissions, and homeowners are eligible for a federal tax credit,” DeVries adds.

Joe Langlois, executive director of engineering and marketing, ECR International, also shares what his company is doing to certify its oil products to meet B100 biofuels.

“Individual states have already adopted different biofuel blends and include different implementation time lines,” he notes. “In order to get ahead of the legislation taking place, ECR is moving forward with B100 biofuels on all our appliances.

Other Regs

“It is a very busy time in the regulatory area of the industry right now and, unfortunately, with very little harmonization across federal, state and local requirements,” notes Dan Moffroid, director of product management, Bosch Home Comfort.

Rettig adds: “When you look at different parts of the United States, the trends are more around regulations/mandates. Boiler manufacturers need to keep in the know about all the state and local codes. They need to fully understand the implementation and enforcement of the codes so they can make sure relevant products are included in the changing market.”

While we’ve touched on federal and local matters — in particular addressing efficiency and electrification — Renee Eddy, vice president of innovation, Rinnai, gave us a summary of some of the other changes in store for the hydronics industry:

• Emissions regulations being proposed at the local level will impact designs in the residential and commercial boiler space. For example, the South Coast Air Quality Management District and the Bay Area Air Quality Management District propose zero NOx and carbon monoxide emissions that will potentially drive new technology and fuels for the boiler space.

• At the state level, examples of substance regulations being proposed are per- and polyfluoroalkyl substances (PFAS) and the Toxic Substances Control Act from the EPA. These regulations require all manufacturers to review component compliance and identify alternative options for components not meeting the regulatory requirements.

• At the federal level, the Consumer Product Safety Commission published a proposed safety standard for gas furnaces and boilers to monitor carbon monoxide levels that require design changes to boilers going forward. 

• Also at the federal level, the Department of the Treasury and IRS propose to put in place product identification numbers to claim tax credits for certain product categories, driving a need to place a unique identification number on all units being sold.

We haven’t heard much about PFAS before this year’s boiler report, or at least in terms of how it affects hydronic equipment. Readers may have heard them referred to by the phrase “forever chemicals,” thousands of long-lasting chemicals that break down very slowly and are widely used in hundreds of products. Most of the press reports we’ve read to date on forever chemicals discuss the harm they pose when leaching into drinking water supplies.

However, after we did some research after reading about this issue, we did find one story on how PFAS regulations could affect heat pumps. Maine, for example, is a state that’s made great strides recently to nudge residents to install heat pumps. 

Because Maine’s current law defines PFAS so broadly, existing heat pump technology could be banned in the state. 

“According to Maine’s current broad PFAS law, the [hydrofluoroolefins (HFOs)] in heat pumps — molecules made up of hydrogen, fluorine and carbon with a double bond — are PFAS,” according to an editorial published last March in the Portland Press Herald. “Yet, HFOs have been studied and approved for use by the U.S. Environmental Protection Agency. They are an energy-efficient technology used in refrigeration. 

“Because they are integral to heat pumps and used in many more technologies that reduce carbon emissions — building and roofing insulation, ultra-low emission pharmaceutical meter-dose inhalers and more — they are integral to Maine’s climate goals.”

Other manufacturers mentioned this issue as well as the carbon monoxide matter designed to shut down residential gas-fired boilers and furnaces based on carbon monoxide levels.

Langlois didn’t expect the measure to take place in our specific time frame of the next 18 months.

“However, it will be a large undertaking for us to comply,” he adds.