IECC Climate Zone 4

Insulation Standards for
Seattle, WA

Seattle's damp Zone 4 marine climate demands insulation that resists moisture while keeping heat in during chilly winters.

Advanced ROI Calculator

Calculate savings based on your local climate & energy rates.

Retrofit Target
R-49
Recommended
New Code (2021)
R-60
Strict Standard
Climate Type
Mixed (Mid-Atlantic)
Source: DOE / IECC

Estimated Insulation Costs in Seattle

Material TypeCost per Sq. Ft.Avg. 1000 sq.ft. Project
Blown-in Fiberglass$2.10 - $3.30$2100 - $3300
Spray Foam (Closed Cell)$5.25 - $8.25$5250 - $8250
Estimates based on Zone 4 material requirements. Local labor rates in WA may vary.

Why Insulation Matters in Seattle

Living in Seattle means dealing with the specific thermal challenges of Climate Zone 4. According to the 2021 International Energy Conservation Code (IECC), homes in this region require specific thermal protection to maintain efficiency and comfort.

💡 Local Energy Tip

Many homes built before 2010 in the 98101 area typically have insulation levels between R-15 and R-30. Upgrading to R-49 is often the single most effective way to lower your utility bills.

Recommended Materials for Zone 4

  • Blown-in Cellulose: Excellent for filling gaps and settling over existing insulation in older Seattle attics.
  • Spray Foam: Provides both high R-value and air sealing, crucial for preventing drafts in Zone 4.

Ready to Upgrade?

Don't guess with your energy bills. We recommend getting quotes from at least 3 licensed insulation contractors in WA to compare pricing.

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