Codes & Permits

IECC

Also known as: International Energy Conservation Code

The model energy code governing building envelope, HVAC, lighting, and water heating efficiency in commercial and residential buildings.

The International Energy Conservation Code (IECC) is the model energy code published by the International Code Council. It governs building envelope insulation, fenestration U-values, air leakage, HVAC efficiency, lighting power density, and water heating efficiency. Compliance is typically demonstrated through prescriptive paths (specific R-values, U-values, equipment efficiencies) or performance paths (whole-building energy modeling).

Most states adopt some version of the IECC. Updates come on a 3-year cycle (most recent: 2024). Energy compliance documentation (often called the COMcheck or REScheck report) is typically submitted with the building permit application. Failure to meet IECC requirements can prevent permit issuance or certificate of occupancy.

Frequently asked questions

What does the IECC regulate?+

Building energy efficiency: envelope insulation, fenestration U-values, air leakage, HVAC efficiency, lighting power density, water heating. Compliance is verified at design (prescriptive or performance path) and at inspection.

How is IECC compliance demonstrated?+

Either prescriptive path (meet specific R-values, U-values, and equipment efficiencies listed in the code) or performance path (whole-building energy model demonstrating compliance via simulation). Most permits use prescriptive path with COMcheck or REScheck reports.

Does the IECC apply to renovations?+

Partially. New construction must fully comply. Renovations and tenant improvements typically must bring altered components up to current IECC standards but may grandfather existing components. Specific scope depends on the adopted edition and jurisdiction.

Related terms

IBC

The model building code for commercial and high-rise residential construction in the United States, adopted in some form by all 50 states.

Permit

AHJ-issued authorization to perform specific work on a building. Required before construction begins.

Inspection

A regulatory review by the AHJ verifying completed work complies with code, required at multiple project milestones.

AHJ

The local agency or official with the legal authority to interpret and enforce building, fire, and life-safety codes.