Climate ZonesConnecticut

Connecticut HVAC Climate Zones

Connecticut is in IECC Climate Zone 5A (Cool - Humid). Get accurate Manual J load calculations with official design temperatures and IECC requirements.

Find Your Connecticut Climate Zone

Climate Zone in Connecticut

Climate Zone 5A

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Cool - Humid

Design Temperatures

Winter
0°F
Summer
91°F
Wet Bulb
75°F

IECC 2021 Requirements

Wall:R-20
Roof:R-49
Floor:R-30
Window U:0.3

Load Characteristic

Heating-Dominated
humid Climate

Recommended Equipment for Connecticut

Based on Climate Zone 5A (Cool - Humid), here are typical HVAC equipment specifications for Connecticut installations.

Heating Systems

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

Annual Fuel Utilization Efficiency for Connecticut furnaces

Cooling Systems

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

Seasonal Energy Efficiency Ratio for Connecticut AC systems

Why Accurate Climate Data Matters in Connecticut

Accurate Sizing

Connecticut's climate zone data ensures proper equipment sizing. No more callbacks from oversized or undersized systems.

Code Compliance

Connecticut building departments require IECC-compliant Manual J calculations. Our tool uses official Connecticut climate data.

Energy Savings

Right-sized systems based on Connecticut climate data reduce energy costs for homeowners and improve your reputation.

Get Free Manual J Calculations for Connecticut

Upload your Connecticut blueprint and get a professional Manual J load calculation with official climate zone data. First report is FREE.

Zone 5A design temps
IECC 2021 compliant
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Climate Zones by City in Connecticut

Get detailed climate zone information for major cities

Need Connecticut HVAC permit forms and building department contacts?

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