New updates to Washington State Energy Code bring sustainability to the forefront

Changes are coming to the Washington State Energy Code.


Written to maintain Washington State's status as one of the nation's leaders in sustainable building design, several aggressive updates have been made to the state's 2015 code, including requirements for dedicated outdoor air systems and a series of sustainable design prerequisites project teams must choose from.

A new requirement for inclusion of a dedicated outdoor air system (DOAS) stands to change how engineers and architects alike approach design. Designers are now required to decouple the heating and cooling system from ventilation systems. According to the new code language, HVAC systems should now include "supply-air temperature controls that automatically reset the supply-air temperature in response to representative building loads, or to outdoor air temperatures." Because these systems have traditionally been linked, heating and cooling equipment have become major sources of wasted energy-pushing fans unnecessarily hard to maintain optimum comfort levels. The new approach will greatly reduce overcooling or overheating interior spaces and mitigate wasted fan energy.

The change will force manufacturers to innovate new solutions, since packaged rooftop units will no longer be viable. There is a side benefit to the overall design, however. While HVAC systems will require more equipment, the overall size of that equipment could potentially decrease, creating the opportunity to increase ceiling heights.

Also new to the code is a selection of energy-efficient design strategies, of which design teams must choose a minimum of two to be code-compliant. Of the available options, a focus seems to be on reduction of both lighting loads and fossil fuel usage. The code updates focus on enhanced lighting controls, a 25% reduction in lighting power, onsite renewable energy, and high-efficiency domestic hot-water sources for 60% of the load (e.g., waste-heat recovery or solar hot-water systems). These features are designed to imbue future projects with greater efficiencies and sustainable designs.

These changes will add costs and additional design considerations. It's recommended that project teams take advantage of the interim year by providing alternative designs featuring the DOAS to allow developers and architects to adjust to the new pricing and timelines. This will help spread awareness of the new code and avoid surprise costs once they truly go into effect.

-Max Wilson, PE, LEED AP, BEMP, is senior energy analyst at Glumac, a CFE Media content partner. This article originally appeared on

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