March 15, 2025
Washington State Building Code Council
ATTN: Council Members via sbcc@des.wa.gov
1500 Jefferson Street SE
P.O. Box 41449
Olympia WA 98504
RE: Site vs Source
Council Members:
The Northwest Gas Association (NWGA) represents the natural gas pipelines and utilities that deliver energy to 10 million residents and 350,000 businesses and industries across the Pacific Northwest. On behalf of our Washington members, NWGA encourages the Council to adopt source energy as the appropriate metric in the state code.
The Council will recall that the 2021 code initially mandated the use of heat pumps and banned the use of fuel-fired equipment for space and water heating. The Berkley decision resulted in an about-face and the TAG then developed the Fossil Fuel Path. However, this Fossil Fuel Path required additional efficiency credits that were 2X to 7X more than that required for using electric space and water heating equipment. The reason for this extremely disparate requirement is that fuel-fired equipment was being compared to electric heat pumps on a site energy basis. This “penalty” is in clear violation of RCW 19.27A.020 (3) that states, “The Washington state energy code may not in any way prohibit, penalize, or discourage the use of gas for any form of heating, or for uses related to any appliance or equipment, in any building.”
The current proposal from RMI (Proposal #279) strikes the Fossil Fuel Path and creates a single efficiency credits table, but the credits are calculated again on a site energy basis using the least efficient fuel-fired equipment as the baseline. The result is basically the same as the Fossil Fuel Path, requiring many more options to gain enough efficiency credits if using fuel-fired equipment. For example, an R-2 multifamily (MF) development would require a total of 290 additional efficiency credits. Simply installing an electric heat pump water heating system with an efficiency of 3.0 COP would earn 293 credits. On the other hand, the same MF development installing a 97% efficient natural gas water heating system would earn 70 credits which would be 220 credits short of what is required. That project would have to install additional measures as shown below to make up the difference.
• High-performance dedicated outdoor air system (DOAS).
• Lamp efficacy. No less than 95 percent of the permanently installed light fixtures in dwelling units and sleeping units shall be provided by lamps with a minimum efficacy of 90 lumens per watt.
• On-site and off-site renewable energy.
• Shower drain heat recovery.
• Service hot water distribution right sizing.
• Enhanced reduced air leakage.
The incremental cost to do this would result in an extreme penalty for that project to use natural gas and would still violate RCW 19.27A.020 (3)
The use of site energy to calculate the efficiency credits in the manner proposed in RMI’s proposal is technically flawed and not appropriate for use in this code. Different energy sources are delivered to the site at different levels of efficiency. The use of site energy as a metric ignores all the upstream losses associated with extraction, generation, transmission and distribution of an energy source and assumes that the energy is delivered to the site at 100% efficiency. Of course, this is not true. For example, using site energy would rate electric resistance heating better than a 98% efficient gas heating system when all other metrics (energy cost, GHG emissions and source energy) would rate it worse. Site energy must never be used as the metric when comparing different energy sources.
Site energy is used to calculate credits in the 2024 IECC, but the credits are calculated by comparing like energy sources. In other words, electric equipment is compared to an electric baseline and gas equipment is compared to a gas baseline. In that case, without fuel-switching, the use of site energy works.
The TAG Chair has stated that he has spent a lot of time reviewing the language in EPCA and that it is clear to him that the use of site energy is required and that source energy is not allowed. That is a clear misinterpretation of the law. EPCA states that “Energy use” is defined as “the quantity of energy directly consumed by a consumer product at point of use . . .”. “Energy” is defined as “electricity, or fossil fuels.” Of course, energy use can only be measured at the meter or point of use, but that does not translate to a requirement to use “site” energy as THE metric in a code or standard. Other standards, such as ASHRAE Std 228-2023 mentioned below use source rather than site energy as the metric in its evaluation methodology. The IECC also allows for the use of source energy as an exception to using energy cost.
Both the EPA and USDOE recommend or acknowledge that source energy is the technically correct metric to use when evaluating energy efficiency options for a building.
EPA Recommends Using Source Energy
“EPA has determined that source energy is the most equitable unit of evaluation for comparing different buildings to each other. Source energy represents the total amount of raw fuel that is required to operate the building. It incorporates all transmission, delivery, and production losses. By taking all energy use into account, the score provides a complete assessment of energy efficiency in a building.” In a 2009 letter to the ICC, Jean Lupinacci, Chief, ENERGY STAR Commercial and Industrial Buildings Branch to the ICC stated, “The use of source energy is the most equitable approach to assessing and comparing the energy efficiency of buildings.” The letter goes on to state, “Therefore, the only way to assess the relative efficiencies of buildings with varying proportions of primary and secondary energy consumption is to convert these two types of energy into equivalent units of raw fuel consumed to generate that one unit of energy consumed on site. Using source energy achieves this equivalency.”
In 2011, the DOE issued a “Statement of Policy for Adopting Full-Fuel-Cycle [source energy] Analyses into Energy Conservation Standards Program,” which states that DOE will use full-fuel-cycle measures of energy use and emissions when evaluating energy conservation standards for appliances, following the recommendation of the National Academy of Sciences.
In 2015, the USDOE engaged The National Institute of Building Sciences to develop a “Common Definition for Zero Energy Buildings.” That work resulted in a definition of a zero energy building to be, “An energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy.”
ANSI/ASHRAE Standard 228-2023, Standard Method of Evaluating Zero Net Energy and Zero Net Carbon Building Performance, states that, “For energy, the committee has chosen to define the calculation in terms of source.”
Using source rather than site energy to calculate the efficiency credits would provide a more equitable and accurate estimate of the total energy used or saved. Pivoting to source would be relatively easy to accomplish. Site energy use and efficiencies would be divided by the appropriate source energy factor to determine those source energy metrics. ASHRAE Std 105-2021 is an ANSI approved standard that can be referenced for those source energy factors. A proposal to use source rather than site energy in the calculation of efficiency credits was presented and discussed at the Feb. 28 TAG meeting. That proposal was postponed pending a decision by the SBCC on this issue.
NWGA urges the Council to adopt source energy as the appropriate metric in the code. If the Council decides to use site energy, it must direct the TAG that any calculations for energy credits, the performance path or the TSPR section only compares like energy sources (gas-to-gas, electric-to-electric) and does not allow the use of site energy to compare different energy sources (electric to gas).
I have asked Gary Heikkinen to speak to the NWGA’s comments at the upcoming Council meeting. Gary is eminently qualified to address the topic of site vs source energy and will answer questions Council members may have on the topic.
Thank you for the opportunity to comment on this important matter.
Sincerely,
DAN S. KIRSCHNER
Chief Executive Officer
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