What to Expect Under the 2015 IECC, Part 1

November 19, 2014 | Ryan Meres

This blog post is the first of a two-part series for Builder Magazine on what the 2015 International Energy Conservation Code means for home builders.

Are you ready for the 2015 International Energy Conservation Code (IECC)? In October 2013 code officials descended upon Atlantic City, N.J. to cast their votes for proposed changes to the 2012 IECC at the International Code Council Public Comment Hearings. Those approved changes are now included in the recently published 2015 IECC. As with any building code, it has to be adopted by a state or local jurisdiction before it takes effect. However, with roughly half of the states currently under the 2009 IECC, many are considering the 2015 IECC as their next energy code. In fact, more than a dozen states and cities have already adopted or are beginning the adoption process for the 2015 code. This will affect homebuilders across the country.

In terms of overall energy savings, the 2015 IECC is not significantly different than the 2012 version. It is, however, roughly 15 percent better than the 2009 IECC. This will mean a jump in energy targets is in the future for a number of states.

The 2015 IECC aims to be more user-friendly, in order to make it easier to realize the targeted energy savings. We’ll summarize a series of changes in the code in a separate blog post. For now, however, we want to focus on the biggest change to affect builders: the introduction of a new Energy Rating Index (ERI) compliance path. The ERI compliance path represents an important evolutionary step toward a code based on whole-house energy consumption and not a debate over specific values of individual components.

The voluntary ERI compliance path for the 2015 IECC gives builders the option of complying with the code by meeting a target Energy Rating Index score. This is a numerical score where 100 equates to the levels prescribed in the 2006 IECC and 0 is equivalent to a net-zero-energy home. One example of this score is RESNET’s Home Energy Rating System (HERS) rating, a tool already being used to rate one-third of all new homes. In addition to meeting the ERI target for a home’s climate zone, under the ERI compliance path a builder must also meet minimum envelope requirements not less than the 2009 IECC levels.

HERS Index that each climate zone must meet under the 2015 IECC:

  • Climate Zones 1 and 2: 52
  • Climate Zone 3: 51
  • Climate Zone 4: 54
  • Climate Zone 5: 55
  • Climate Zone 6: 54
  • Climate Zones 7 and 8: 53

When introduced, the ERI provision was supported by more than 20 of the country’s biggest homebuilders—including Meritage Homes, Pulte Group, and KB Homes—and 90 small builders and other building industry businesses and nonprofits, including the Institute for Market Transformation, where I work. We believe that this compliance path is a win for builders, as it allows you to select the most cost-effective energy efficiency measures to achieve the best performance for each home depending on its climate zone, rather than installing a series of prescriptive measures.

This benefits your bottom line: Research conducted for the Leading Builders of America by The Home Innovation Research Laboratory found that using an ERI-based approach allows builders to achieve identical energy savings as those achieved through the prescriptive path, but at a reduced cost of $1,700 for the typical new home. The research found that the cost of complying with the prescriptive path was about $3,000, while identical levels of efficiency could be achieved under the ERI path for about $1,300 (which includes the cost of the rating).  The ERI compliance option keeps construction costs lower because of the added flexibility in how compliance is achieved. Builders can consider equipment as well as the building envelope in calculating their ERI score.

Another benefit is marketability. Consumers expect a new home to be built in compliance with local building codes, but they don’t understand what “compliance with the energy code” means. However, providing consumers with an ERI score allows homebuyers to better understand the efficiency of a house and compare House A to House B. The homebuyers win as well, as meeting the efficiency standards of the ERI compliance option should save them roughly $300 annually on their utility bills compared to the 2012 IECC and $850 annually compared to homes built to the 2006 IECC.

There is also an added benefit for builders that are already building to Energy Star or using HERS. The ERI option now gives those builders a way to more easily demonstrate compliance to the local building official. 

Overall, the ERI compliance option provides design flexibility that can lead to significant cost savings over the prescriptive path, while also allowing homebuyers to understand a home’s energy efficiency and save money on utility bills. As states look to adopt the 2015 IECC, builders should make their voice heard about the ERI compliance option.

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Ryan Meres

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