Saint Louis, Missouri HVAC Climate Zone

Saint Louis is located in IECC Climate Zone 4A (Mixed - Humid). Get accurate Manual J load calculations with official design temperatures for Saint Louis.

Climate Zone
4A
Winter Design
13°F
Summer Design
91°F
ZIP Codes
67

Saint Louis HVAC Contractors: Get Your Free Manual J Report

Climate Zone 4A requires precise load calculations. Upload your Saint Louis blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Saint Louis's exact design temperatures (13°F winter / 91°F summer).

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Verify Your Saint Louis ZIP Code

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

Saint Louis covers 67 ZIP codes: 63101, 63102, 63103, 63104, 63105, 63106, 63107, 63108, 63109, 63110 and 57 more

Saint Louis Design Temperatures

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

Winter 99% Design Temp
13°F
Summer 1% Design Temp
91°F
Summer Wet Bulb
75°F

IECC Requirements for Zone 4A

Minimum insulation and window requirements for Saint Louis 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: 2020 IECC

Recommended HVAC Equipment for Saint Louis

Heating Systems

Gas furnace (90%+ AFUE)
Heat pump
Typical AFUE
92-96%

Cooling Systems

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

Get Free Manual J Calculations for Saint Louis

Upload your Saint Louis blueprint and get a professional Manual J load calculation using official Zone 4A design temperatures. First report is FREE.

Saint Louis design temps
Zone 4A compliant
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