Washington, Idaho HVAC Climate Zone

Washington is located in IECC Climate Zone 5B (Cool - Dry). Get accurate Manual J load calculations with official design temperatures for Washington.

Climate Zone
5B
Winter Design
-7°F
Summer Design
91°F
ZIP Codes
3

Washington HVAC Contractors: Get Your Free Manual J Report

Climate Zone 5B requires precise load calculations. Upload your Washington blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Washington's exact design temperatures (-7°F winter / 91°F summer).

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Verify Your Washington ZIP Code

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

Washington covers 3 ZIP codes: 83610, 83645, 83672

Washington Design Temperatures

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

Winter 99% Design Temp
-7°F
Summer 1% Design Temp
91°F
Summer Wet Bulb
63°F

IECC Requirements for Zone 5B

Minimum insulation and window requirements for Washington per IECC 2021.

Wall Insulation:R-20
Roof/Ceiling:R-49
Floor Insulation:R-30
Window U-Factor:0.3
Window SHGC:0.4

Energy Code: 2021 IECC

Recommended HVAC Equipment for Washington

Heating Systems

Gas furnace (95%+ AFUE)
Typical AFUE
95-98%

Cooling Systems

AC (13-15 SEER)
Typical SEER
13-15 SEER

Get Free Manual J Calculations for Washington

Upload your Washington blueprint and get a professional Manual J load calculation using official Zone 5B design temperatures. First report is FREE.

Washington design temps
Zone 5B compliant
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