2015 International Green Construction Code (Green Codes)

Codes And Policy

IgCC logoThe International Green Construction Code (IgCC) is an effort of the International Code Council (ICC) aimed at creating a new green overlay code for the ICC’s suite of I-Codes.  The IgCC includes requirements for a range of issues pertinent to sustainability, including a substantial portion dedicated to energy efficiency.As an “overlay” code, the IgCC works in combination with other underlying codes including the 2015 International Energy Conservation Code and the entire suite of I-Codes.

Development of the 2015 IgCC concluded with adoption of a number of important proposals supported by NBI and various partners.

Tool 1 | Outcome-Based Compliance

Energy codes offer two primary pathways to demonstrate required energy savings: modeled and prescriptive. Adoption of the outcome-based compliance proposal provides an additional compliance path and alternative to prescriptive or modeled performance energy compliance in the 2015 IgCC. This provision helps facilitate innovation in design and greatly simplify the task of verifying code compliance.


To help design teams access the energy use targets in the outcome path and more easily apply the new revised modeling path, the IgCC also updated the Zero Energy Performance Index (zEPI), which  presents a stable energy scale for  performance of a building compared to similar average buildings and to measure the progress toward net zero energy. zEPI, conceived by NBI Fellow Charles Eley, uses an absolute scale from 0 to 100 with zero representing a net zero energy building and 100 representing the average energy consumption for that building type and location. Read more about zEPI

Renewable Energy

Over the past several years, onsite renewable energy systems have been evolving and are being deployed at an increasing rate that exceeds the ability of construction codes to keep pace. The 2015 International Code Council family of codes is addressing this need by updating and coordinating enforceable code requirements for the safe installation of onsite renewable energy systems. IgCC adoption of GEW-133-4 clarifies requirements for onsite renewable energy systems and renewable energy credits and make them consistent with other I-Codes.

Demand Response

Demand response (DR) refers to the ability to adjust energy use in response to a price or information signal from a grid operator or other automated source. It enables energy efficiency to be dynamically dispatched, thus lowering costs and increasing reliability, particularly during peak demand periods. Three proposed modifications to the IgCC will ncrease the effectiveness of existing demand response provisions and lead to more buildings with demand-response capabilities. GEW 54-14 proposes to comprehensively revise the DR provisions in the IgCC to reflect language in OpenADR and other codes and GEW 58-14 would expand the scope of demand response applicability to more jurisdictions.