The 2015 International Energy Conservation Code, or IECC, is the updated version of the previous 2012 IECC code adopted by Massachusetts. It introduces a new Energy Rating Index (ERI) compliance path which focuses on whole-house energy consumption rather than specific values of individual components.
This index requires homes to meet a target ERI score using a HERS rating system of 0-100 (with zero being net-zero-energy homes and 100 being typical houses built before 2009 IECC energy requirements) to determine the level of energy efficiency in new homes. It allows builders to select the most cost-effective energy efficiency measures to achieve the best performance for each home depending on its climate zone.
This ERI approach cuts costs nearly in half for builders in their process to achieve levels of energy efficiency for their projects by providing added flexibility in how compliance is achieved. Additionally, this method allows home buyers to better understand the efficiency of a house and how many annual savings they will see on their utility bills.