2015 Seattle Commercial Building Energy Code

-Moving towards a Carbon-Neutral Seattle

Following four public review sessions, the draft 2015 Seattle Commercial Energy Code is now posted on our 2015 Seattle Codes Adoption website. Our thanks to the dozens of local experts who volunteered their time through these hours of meetings, refining and improving the proposals. Seattle is committed to being a carbon-neutral city by the year 2050, and increasing the energy efficiency of our building stock will be a critical component of that transition. (Note that these changes are for “commercial buildings,” as defined in the energy code, and do not apply to houses or other low-rise residential buildings.)

The proposed 2015 amendments to the Seattle Energy Code build on the State code changes that were finalized late last year. The 2015 energy code is scheduled to become mandatory along with the other Seattle construction codes in January of 2017. A few additional changes not shown in this draft are still under consideration for the code, pending approval from City departments. Most of the proposed changes in this draft are corrections, clarifications, or minor exceptions, while a handful are more substantive, including:

  • An additional 10 percent reduction in allowable lighting power, effective January 2018. This takes advantage of the rapidly improving cost-effectiveness of commercial LED lighting.
  • Solar-ready roof requirement extended to buildings up to 20 stories tall. This simply requires roofs and electrical service panels to be readied for future PV systems, which are expected to become cost-effective (even in cloudy Seattle) within the next several years.
  • Slightly more restrictive energy efficiency requirements for “substantial alterations” projects, as well as a cap to the cost of required envelope improvements.
  • Controls on the amount of glazing area beyond code limitations that can be traded against upgrades to other building systems. This reflects the fact that building envelopes typically remain in place unchanged for generations, while lighting and mechanical systems are upgraded on a more frequent basis.
  • Change in the air leakage pressure-testing standard from 0.40 cfm per square foot to 0.30 cfm per square foot of building envelope area. This matches the US Army Corps of Engineers standard, which has been in effect for a decade.

Additional public meetings will be scheduled to resolve any remaining issues. To be added to the energy code mailing list, and to submit comments or corrections, please email:

Duane Jonlin
Energy Code Advisor
(206) 233-2781
duane.jonlin@seattle.gov