Climate ZonesWashingtonSan Juan

San Juan, Washington HVAC Climate Zone

San Juan is located in IECC Climate Zone 4C (Mixed - Marine). Get accurate Manual J load calculations with official design temperatures for San Juan.

Climate Zone
4C
Winter Design
29°F
Summer Design
85°F
ZIP Codes
9

San Juan HVAC Contractors: Get Your Free Manual J Report

Climate Zone 4C requires precise load calculations. Upload your San Juan blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with San Juan's exact design temperatures (29°F winter / 85°F summer).

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Verify Your San Juan ZIP Code

Enter your ZIP code to confirm it's in San Juan and get climate zone details.

San Juan covers 9 ZIP codes: 98222, 98243, 98245, 98250, 98261, 98279, 98280, 98286, 98297

San Juan Design Temperatures

Official ASHRAE design temperatures for San Juan, used for accurate Manual J load calculations.

Winter 99% Design Temp
29°F
Summer 1% Design Temp
85°F
Summer Wet Bulb
67°F

IECC Requirements for Zone 4C

Minimum insulation and window requirements for San Juan per IECC 2021.

Wall Insulation:R-20
Roof/Ceiling:R-49
Floor Insulation:R-19
Window U-Factor:0.32
Window SHGC:0.4

Energy Code: 2021 IECC

Recommended HVAC Equipment for San Juan

Heating Systems

Gas furnace
Heat pump
Typical AFUE
92-95%

Cooling Systems

AC (optional)
Heat pump
Typical SEER
14 SEER

Related Climate Zone Pages

Learn More About
Climate Zone 4C
View All Zones in
Washington
HVAC Permits for
San Juan, Washington

Get Free Manual J Calculations for San Juan

Upload your San Juan blueprint and get a professional Manual J load calculation using official Zone 4C design temperatures. First report is FREE.

San Juan design temps
Zone 4C compliant
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