The expansion of the California Home Energy Rating System (HERS) residential rating system for use on non-residential buildings is causing consternation in many quarters in the Golden State.
A recent white paper commissioned by the Joint Committee on Energy and Environmental Policy, a collaboration between the California Sheet Metal Air Conditioning Contractors National Association and Sheet Metal Workers International Association (SMWIA), shows why. The current California Energy Commission (CEC) procedures for testing non-residential HVAC systems fail to address “… more than 56 percent of the floor area, i.e., larger buildings in the state of California,” wrote James E. Wood, Ph.D., executive director of The Building Diagnostics Research Institute in Chevy Chase, Md.
“These large buildings are likely to have more occupants and to consume more energy than the 44 percent of the buildings characterized as small in the2003 Small HVAC System Design Guide,” one of the guides used for the proposed expansion. As the CEC moves towards verification of systems in non-residential buildings, it has turned to the HERS.
“The HERS raters do a good job on residential systems,” said Glenn C. Hourahan, vice president, Research and Technology of the Air Conditioning Contractors of America (ACCA). “However, when you expand into commercial building applications, HERS starts to fall down.
“At a certain point, [it] doesn’t apply at all. The HERS process doesn’t have the metrics, standards, or protocol to properly evaluate commercial buildings.”
“The expansion of the HERS to the environment is inadequate,” said Bruce Word, business manager for Local 104, SMWIA. “There really isn’t a current system capable of accomplishing the energy requirements we’re trying to achieve for commercial systems.”
In addition to a lack of standards, raters themselves do not have the training or experience needed for the non-residential building system verification arena.
“A totally different skill set would be required,” said Eli P. Howard, III, executive director Technical Services, Sheet Metal Air Conditioning Contractors of North America (SMACNA). “Home Energy Raters won’t be able to handle it because they don’t have the training or experience needed for commercial systems.”
Although the paper showed the need for more study of the issue, many feel the findings of the paper were too conservative. For some, not even the 44 percent of non-residential floor area assumed to be verified by the CEC would fit the Home Energy Rating System air leakage testing procedures.
“It’s a very narrow slice of nonresidential systems that meet the prescriptive standard with HERS requirements. Anecdotally, I’d say, less than 5 percent,” said Mike Gabel, principal of Gabel Associates, an energy consulting firm with nearly 30 years in the industry.
“The design and technology is sufficiently different for commercial buildings that we need a different paradigm for third-party verification. HERS works for residential and the limited number of commercial cases it was designed for, but we need a fundamentally different approach for verifying HVAC performance in non-residential buildings,” said Gabel.
Even HERS raters see the flaws in expanding the current system. “HERS really only deals with units smaller than 7.5 tons,” said Jim Rosier, vice president of Equal Air Balance, a HERS rater with more than 40 years in the industry. “It’s an excellent system for residential, but at this particular junction, I don’t think HERS raters are qualified to do large commercial work.”
Like many in the industry, Rosier is proposing a different set of standards be put into place. “You could test duct work to the higher standards of SMACNA, then CEC should set a standard for acceptable equipment leakage; we can apply that standard, and test equipment to that protocol.”
“We have the standard already out there, we just need to enforce it,” agreed SMACNA’s Howard.
People who train and certify HERS raters know, “There’s a huge amount of kilowatts out there to be saved through testing, measuring, and verification,” said Mike Bachand, president of Cal Certs, one of three businesses approved by California to regulate the raters.
Bachand would like to see other sections of the standards, such as lighting efficiency, go to more highly trained raters while acknowledging that, “A huge amount of airflow in large commercial systems doesn’t really lend itself to HERS rating, using the existing protocols. The amount of training and education needed to get up to that knowledge base is very involved.”
No matter what standards are adopted, everyone agrees that improving HVAC energy efficiency has to be the goal to reducing air leakage in HVAC systems.
“Whether it’s HERS or something else, to see improved energy efficiency in non-residential HVAC systems, we have to ensure that we have the proper methods to not only design [and construct] systems for less air leakage, but we must also have the proper enforcement provisions to confirm less air leakage is achieved,” said Kent Peterson, vice president and chief engineer of P2S Engineering, who is also a presidential member of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. “That’s the bottom line.”
With California facing ever-mounting energy problems, finding a system to accurately test and measure energy efficiency in large non-residential buildings is essential. The question facing Californians now is how to go about it in a responsible manner.
For more information, click on the PDF link below to access the white paper on HERS mentioned at the top of this article.
HERS Under Commercial Attack
August 31, 2009