With the new 2018 Washington State Energy Code (2018 WSEC) compliance on February 1, 2021 here is our summary of the changes:
Commercial:
- Each space conditioning category shall demonstrate compliance separately.
- Wood-framed wall Group-R requires insulation in cavity R25 (typically 2X8 framing).
- Maximum allowed air leakage has to pass 0.25 cfm/ft@75Pa test.
- C406 – 6 Credits are required. Each occupancy weights each credit differently. Commissioning is required for all credits:
10. Enhanced Envelope 15% Improvement:
- Groups R-1, B, E, M — 3.0 credits
- Group R-2 — 6.0 credits (Full compliance with C406, with one credit)
- All others — 4.0 credits
11. Reduced Air INfiltration 0.17 cfm/ft@75Pa:
- Groups R-1, B, E, M — 1.0 credit
- Group R-2 — 2.0 credits
- All others — 1.0 credit
- C411 Solar Readiness is new to WA for all non-residential buildings up to 20 stories.
- All metal fenestrations, including metal, have to meet U-3.0 (triple glazing for metal) except AW windows.
Residential:
- R406 credit requirements will be doubled.
Small units (1,500 sq.ft.) R406 — 3.0 credits up from 1.5
Medium units (1,500-5,000 sq. ft.) R406 — 6.0 credits up from 3.5
Large units (over 5,000 sq. ft.) R406 — 7.0 credits up from 4.5
R-2 R406 — 4.5 credits up from 2.5
- R406.2 Carbon emission equalization. Electric resistance heaters are penalized.
- Efficient Building Envelope. MAX 3 credits: Triple glazed windows U-0.18; Roof R-60; Wood-framed wall R-21 int + R-16ci; Floor R-48; Entire Slab R-20; OR 40% improvement in energy modeling. Passive House.
- Air Leakage MAX 2 credits: 0.6ACH@50Pa + Heat Recovery Ventilation. Passive House.
- Mechanical credits are more aggressive.
- R401.3 Certificate. Insulation values, equipment efficiency, appliance information.
- R405 Simulated Performance Alternative (Performance) – compliance pass.
- R407 Certified Passive House – compliance pass
