It’s been a little more than two years since the residential boiler minimum federal efficiency standards went into effect. The standards, which were set by the Energy Independence and Security Act (EISA) in 2007 and implemented Sept. 1, 2012, required residential gas hot water boilers to meet a minimum AFUE of 82 percent; gas steam boilers, 80 percent; oil hot water boilers, 84 percent; and oil steam boilers, 82 percent.
In addition to efficiency requirements, the rule required manufacturers to equip each gas, oil, and electric hot water boiler with automatic means for adjusting the temperature for the water supplied by the boiler to ensure an incremental change in inferred heat load, producing a corresponding incremental change in the temperature of water supplied. Additionally, the automatic means had to limit the temperature of the water in the boiler to not more than 140?F when there is no inferred heat load with respect to a hot water boiler.
According to Rich Simons, director of combustion channel management, Honeywell Intl. Inc., the 2012 standards have had a significant impact on manufacturers and contractors.
“Manufacturers, especially those with cast iron boilers in their portfolio, had to essentially redesign and retool their entire boiler lines — oil and gas — while their condensing-only competitors did not,” Simons said. “They then had to launch a number of new products and train their distributors and contractors accordingly. For contractors who were content with installing standing-pilot-only boilers, they’ve had to shift their focus to electronic ignition. Ultimately, all contractors have had to learn new electronic controls, which is definitely a very big deal in the industry.
“As with any broad-based changeover, implementation and training throughout the whole channel takes time to get fully up to speed,” Simons added. “Now that we’re through that phase, the industry can claim a more modern look and feel and be well-positioned to improve long-term consumer perceptions of combating rising energy costs.”
Frank Stanonik, chief technical advisor, Air-Conditioning, Heating, and Refrigeration Institute (AHRI), said consumers have clearly benefited from the automatic means for adjusting the water temperature requirement.
“The changes increase the efficiency by a few points, which is obviously beneficial to customers,” he said.
“But, really, the bigger change is this control scheme, if you will, that attempts to control how long your burner fires based on how cold it is outside, and that does offer a savings for consumers. The difficulty has been that the benefit of this control process doesn’t show up in the test procedures that manufacturers have to use. That’s why the requirement was written the way it was. Even though consumers are getting a product that, theoretically, is only two points higher in efficiency, they are getting a product that, in application, will operate more efficiently than simply a boiler that had an 80 percent AFUE and didn’t have what we call this automatic means for adjusting for the load. That’s definitely been an advantage for consumers.”
Of the estimates Stanonik has seen, the automatic means feature can save consumers 5-20 percent on their energy bills, depending on the size of the boilers. For most residential customers, it will likely be in the 5-10 percent range.
“This standard, this most recent change — in terms of how the boiler is operating — is probably saving more energy than if we were just talking about taking up the efficiency two to three points. It’s kind of a strange situation because it doesn’t show up in the lab running a test on it to measure AFUE.”
Total System Balance
Dan Holohan, owner, HeatingHelp.com, said that while an increase of a few percentage points in efficiency really doesn’t have much of an impact on any one job, it does add up when everyone is doing the same thing.
“It’s [the standard] certainly caused people to talk more about high efficiency, but that’s such a malleable term,” Holohan said. “What’s the point of having a high-efficiency boiler in a system that is out of whack in terms of size, control strategy, or balance? There are so many of those. The 2012 standards touch one part of the elephant, but not the whole beast. Professionals know the whole system has to come together before real efficiency takes place, and we’d have to move to Europe to find standards that do that.”
“From my perspective, the problems we see in the industry are not necessarily because the boiler has low efficiency or that the boiler isn’t operating correctly, but that the boiler has been put into a system that doesn’t allow it to perform optimally,” said John Siegenthaler, principal, Appropriate Designs, Holland Patent, New York. “It could be any number of issues, including inadequate piping, incorrect piping design to begin with, or the wrong selection or sizing of circulators.
“If there’s a new standard that requires all boilers to be 2 percent more efficient, it really isn’t going to help that issue,” he continued. “Because, even if it’s a better designed boiler, the fundamental thermodynamics and the chemistry of combustion limit what it can do if it’s applied in a high-temperature system. We see this quite often.”
According to Siegenthaler, contractors like the new boilers because they’re smaller, lighter, and they mount on the wall, which are all desirable traits from an installation standpoint. But, in terms of performance, if the distribution system is not well matched to the boiler, it, in turn, will not perform at its optimal efficiency rating.
“I emphasize to people that it’s a system, not just a boiler,” he said. “It’s important to look beyond the boiler — don’t judge the quality of the system solely on the boiler. I tell people I want to get into Formula 1 racing and my plan is to go to Italy and buy a Ferrari racing engine then bring it home and install it in my Cub Cadet lawn tractor. They immediately recognize that it’s a really bad match, and, yet, that’s what happens to an extent with high-performance heat sources — be it modulating condensing boilers, geothermal heat pumps, solar collectors, or any of the renewable heat sources that are out there — they operate best at these low water temperatures.”
In order to fully realize and optimize performance, contractors should be looking at the entire distribution system and modifying as needed, Siegenthaler said.
“Unfortunately, that involves cost. There are many different ways they [contractors] can do this, but, ultimately, they have to add more heat emitter surface area. And, of course, you get push back on that because instead of just changing the box down in the basement, so to speak, contractors now have to be in the house, and they have to perhaps disrupt some of the existing baseboard or add some more heat emitter surface area. Quite honestly, most contractors don’t relish doing that. Those who do see it as a profitable opportunity. And, some homeowners think upgrading their heating system is just a matter of changing from an old boiler to a new boiler. It’s certainly going to buy them longevity, but, as far as a real performance gain, it might not have much effect on their fuel use because if you don’t allow these boilers to operate at the peak efficiency, you simply use more fuel for the same amount of heat delivery.”
Publication date: 1/19/2015