IECC climate zone
International Energy Conservation Code climate zone
The building-code climate map that sets insulation and energy requirements by region. North Carolina spans IECC zones 3A, 4A, and 5A — warm Piedmont and coast to cold mountains.
What it means for you
Don't confuse it with ENERGY STAR's window zones — they're a different map for a different purpose. The IECC zone drives code minimums for a build or addition; ENERGY STAR zones drive which window U-factor and SHGC earn the label. A salesperson mixing them up is a small credibility tell.
Where you'll see it
In code and permit discussions and on sunroom or addition plans.
Don't be fooled
IECC building-code zones (3A/4A/5A) are NOT the same as ENERGY STAR window zones — don't let the two maps get blended in a pitch.
Related terms
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