Energy code compliance package

What's required

The Seattle Energy Code (SEC, 2021 edition with amendments) drives a handful of specific requirements on a new DADU:

• Heat pump for space heating (the design-team default; gas furnaces are increasingly out of favor).
• Envelope U-values — wall, ceiling, floor, window, door — meeting prescriptive or performance compliance paths.
• Air sealing — blower-door test ≤ 5 ACH50 (or 0.4 cfm/sf alt for attached).
• Duct leakage — ≤ 4 CFM25 per 100 sf if ducted.
• Ventilation — HRV/ERV per code prescriptions.
• Lighting and water-heating efficiency requirements.

The deliverables

• Filled-out SEC compliance forms (matching the chosen path).
• U-value calcs for each envelope assembly.
• Heat-pump sizing calc (Manual J).
• Ventilation design.

Who does this

Usually the architect's office produces the package or contracts it to a specialist. Standalone energy consultants are useful on owner-build or designer-led projects without an architect.

Cost

• Forms package: $500 – $1,500.
• Blower-door test (later, during build, step 5.6): $300 – $600.
• Duct-leakage test (later, step 5.6): $250 – $450.

Sequencing

Engage in parallel with structural (step 2.3) and civil (step 2.4), after schematic. The deliverable is part of the permit submittal in step 3.1.