YES — Washington has adopted 2021 Washington State Energy Code which requires HVAC loads be calculated per ACCA Manual J for new construction and major renovations.
Washington has adopted 2021 Washington State Energy Code as the statewide energy code for residential construction.
Primary zone covering Seattle and surrounding areas
Additional zone in Washington
Additional zone in Washington
Local Washington contractors typically charge $150-400 for Manual J calculations. AutoHVAC offers your first Manual J calculation completely FREE with permit-ready results in 60 seconds — no credit card required.
Yes. Washington follows 2021 Washington State Energy Code which requires heating and cooling loads be calculated per ACCA Manual J for permits on new construction and major HVAC work.
You can get a free Manual J calculation for Washington instantly at AutoHVAC — upload your blueprint and receive a permit-ready report in 60 seconds. Alternatively, local Washington HVAC contractors charge $150-400 with 3-7 day turnaround, or you can use DIY software like Wrightsoft or CoolCalc ($5-200+/month).
Washington includes IECC climate zones 4C, 5B, 6B. Zone 4C is most common, covering cities like Seattle, Spokane, Tacoma. Climate zone data determines design temperatures and insulation requirements used in Manual J calculations.
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