There’s a New Code in Town

IECC-2015The 2015 International Energy Conservation code has recently been published and we are seeing some local jurisdictions (Denver and Parker) beginning the process of adopting it. This new code is quite different from previous updates, and we’ve identified three unusual aspects of the code change that you should know about.

1. The actual increase in efficiency from the 2012 IECC came out to only 1.5%

As you may know, I-codes are on a three year development cycle. As we completed developing the 2015 I-code, the 2018 I-code development is starting. This cycle is an issue that the International Code Council (ICC) and jurisdictions are struggling with as some feel they need more than three years to implement and understand the implications a new code, especially as they become more complex. Many jurisdictions were unwilling to adopt recent revisions and are now overwhelmed by what will happen with the 2015 adoption. This was revealed during recent code development hearings in October of 2013.  This unwillingness showed efficiency gains from code cycle to code cycle come to a screeching halt with only a 1.5% increase.


2. Not much changed between the 2012 and the 2015 other than cleaning up language and making it more usable

Jurisdictions and Builders who are currently utilizing the 2009 IECC or older will have the most difficulty with a 2012 or 2015 IECC code change adoption.  This is because of mandatory requirements needed to achieve the 15% increase in efficiency above the 2009 IECC and the 30% increase in efficiency above the 2006 IECC (see chart above). That being said, jurisdictions such as Denver who are going from 2009 or older versions are jumping directly to the 2015 IECC rather than going to the 2012 first.  As noted earlier, the 2015 IECC is a better written code than the 2012 IECC, and it has only tweaked the efficiency requirements rather than advance them another 15%. It is likely that many jurisdictions will skip the 2012 and move directly to the 2015 IECC.

3. A fourth compliance pathway was added that utilizes an Energy Rating Index.HERSscore1

The biggest addition to the 2015 IECC is the inclusion in chapter 4 of an additional compliance pathway through the code. Older versions of the IECC had three pathways one could choose from to demonstrate compliance. These are:

  • The prescriptive path:
    • This path mandates minimum levels of insulation in the building envelope based off of a component insulation table for each climate zone in the country. A builder can add more R-value than listed in the table but cannot trade off a lower component R-value in a specific location, an attic for example.
  • The Total UA alternative or UA path: (area weighted U-value (UA))
    • This path allows a Builder to trade off R-values and U-values within the thermal envelop and is most often complied with using the RESCheck software and is sometimes called the RESCheck path. If a Builder would like to put an R-20 in an attic, for example, it would be allowed if the lower energy performance could be traded off for better performance in another component of the building.
  • The simulated performance path:
    • This path offers the most flexibility for tradeoffs and is the path most EnergyLogic builder clients utilize.  In addition to being able to trade off R-values and U-values (conductive energy) this path allows for trading convective energy losses for conductive energy losses and therefore house tightness, duct leakage, ventilation and more are all accounted for in demonstrating compliance.

We are currently teaming with other code experts on writing a white paper that significantly goes in depth on more aspects of this code change.  If you are interested in reading that preliminary , please click here.

If you are interested in attending any classes EnergyLogic is offering on the new code,  follow this link.



Robby Schwarz
Principal and Director of Builder Relations
EnergyLogic, Inc.

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