Climate ZonesOklahomaJohnston

Johnston, Oklahoma HVAC Climate Zone

Johnston is located in IECC Climate Zone 3A (Warm - Humid). Get accurate Manual J load calculations with official design temperatures for Johnston.

Climate Zone
3A
Winter Design
22°F
Summer Design
94°F
ZIP Codes
9

Johnston HVAC Contractors: Get Your Free Manual J Report

Climate Zone 3A requires precise load calculations. Upload your Johnston blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Johnston's exact design temperatures (22°F winter / 94°F summer).

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Verify Your Johnston ZIP Code

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

Johnston covers 9 ZIP codes: 73432, 73447, 73450, 73455, 73460, 73461, 74530, 74836, 74856

Johnston Design Temperatures

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

Winter 99% Design Temp
22°F
Summer 1% Design Temp
94°F
Summer Wet Bulb
75°F

IECC Requirements for Zone 3A

Minimum insulation and window requirements for Johnston per IECC 2021.

Wall Insulation:R-20
Roof/Ceiling:R-30
Floor Insulation:R-19
Window U-Factor:0.32
Window SHGC:0.25

Energy Code: 2021 IECC

Recommended HVAC Equipment for Johnston

Heating Systems

Gas furnace
Heat pump
Typical AFUE
90-95%

Cooling Systems

AC (14-16 SEER)
Heat pump
Typical SEER
14-16 SEER

Related Climate Zone Pages

Learn More About
Climate Zone 3A
View All Zones in
Oklahoma
HVAC Permits for
Johnston, Oklahoma

Get Free Manual J Calculations for Johnston

Upload your Johnston blueprint and get a professional Manual J load calculation using official Zone 3A design temperatures. First report is FREE.

Johnston design temps
Zone 3A compliant
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