The Washington State Building Code Council’s Commercial Energy Code TAG voted Friday to drop a broad requirement for predictive whole‑building energy modeling and instead require that construction documents include an estimated energy‑use intensity (EUI) or other engineering estimate for buildings subject to the Clean Buildings Performance Standard.

The vote followed several hours of debate about whether predictive modeling should be mandatory for many projects, including whether lower‑cost alternatives or thresholds for larger buildings would be more practical.

“Another path would be to provide on the construction documents both estimated energy use intensity based on benchmarking of similar buildings, predicted energy modeling, or other methods,” TAG chair Joe Anderson said during the discussion as members searched for a compromise.

Supporters of mandatory predictive modeling argued it would produce better design decisions and help meet long‑term performance goals. Opponents said the models are costly, often late in design, and can be difficult for building departments to review. Several TAG members suggested a tiered approach — limiting mandatory modeling to larger projects or performance‑path projects, or adding a nonbinding option that owners could use in lieu of full modeling.

To break an impasse, a motion carried to require that construction documents include an estimated EUI (or equivalent engineering calculation or benchmarking summary) instead of a full predictive model, and to remove an earlier proposal (C413) that would have required submission of full performance reports. TAG members asked MVPE staff and PNNL to model the impacts of several approaches and return recommended thresholds and review guidance for future consideration.

The motion to approve the revised approach passed in roll call 9‑3 with two abstentions.

TAG members said the outcome is a step toward better early documentation and owner awareness while avoiding a near‑term, across‑the‑board modeling mandate that many owners and designers said they could not afford or reliably meet.

Next steps: TAG members directed PNNL and staff to quantify the effect of several candidate thresholds (for example, 50,000 sq. ft. or larger, or projects on the performance pathway) and to return with recommended applicability and review procedures before MVPE or council action.