Climate ZonesIllinoisMercer

Mercer, Illinois HVAC Climate Zone

Mercer is located in IECC Climate Zone 5A (Cool - Humid). Get accurate Manual J load calculations with official design temperatures for Mercer.

Climate Zone
5A
Winter Design
0°F
Summer Design
91°F
ZIP Codes
11

Mercer HVAC Contractors: Get Your Free Manual J Report

Climate Zone 5A requires precise load calculations. Upload your Mercer blueprint and get a professional Manual J report in 60 seconds— first report is FREE. Pre-loaded with Mercer's exact design temperatures (0°F winter / 91°F summer).

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Verify Your Mercer ZIP Code

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

Mercer covers 11 ZIP codes: 61231, 61260, 61263, 61272, 61276, 61281, 61442, 61465, 61466, 61476 and 1 more

Mercer Design Temperatures

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

Winter 99% Design Temp
0°F
Summer 1% Design Temp
91°F
Summer Wet Bulb
75°F

IECC Requirements for Zone 5A

Minimum insulation and window requirements for Mercer 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 Mercer

Heating Systems

Gas furnace (95%+ AFUE)
Boiler
Heat pump (cold climate)
Typical AFUE
95-98%

Cooling Systems

AC (13-16 SEER)
Heat pump
Typical SEER
13-16 SEER

Related Climate Zone Pages

Learn More About
Climate Zone 5A
View All Zones in
Illinois
HVAC Permits for
Mercer, Illinois

Get Free Manual J Calculations for Mercer

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

Mercer design temps
Zone 5A compliant
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