Green Zone Home is now inspecting, testing and verifying houses that fall under the City of San Antonio’s 2015 International Energy Conservation Code (IECC) requirements.
The 2015 code is very similar to the 2012 code which the City of Austin is under. One difference is that the 2015 code allows for what is called the Energy Rating Index or ERI. As it stands the RESNET Home Energy Rating System (HERS) ratings are the only way of meeting the ERI. Interestingly the ICC in the IECC sets the rating threshold to hit or be under at 52 in climate zone 2. San Antonio adopted a threshold of 59. The State of Texas is setting it at 65 for when it comes into adoption. We’ve found so far though that most homes will meet the codes prescriptively or using the traditional performance paths (RESCheck, IC3) with HERS ratings higher than the thresholds that have been set.
With the 2012 and 2015 codes though the building standards are really reaching the point to where going beyond them is usually going to require significant increased cost. This is a big step in home energy efficiency. For a home to show differentiation in being significantly more efficient than the codes now a big effort in efficiency or solar is likely to going to be made.