2015 IECC Adoption Western Colorado

Here in western Colorado, local jurisdictions are busily adopting the 2015 building code.  The 2015 IECC adoptions are the most contentious and most heavily modified.  It is hard to keep track what needs to be done to comply with the energy requirements for residential construction.  Below is a cheat sheet table of adoptions and modifications in Western Colorado.  If you need assistance getting the most sustainable home or just figuring out what a jurisdiction wants – give Confluence Architecture a call.  How is the 2015 IECC different than 2009?  See this blog. We do HERS ratings, blower door tests, and code compliance documents for the IECC.

Adopted Residential Energy Codes and Amendments
JurisdictionIRCIECCAmendments to CodeHERS RequiredHERS usable for permitBlower Door Required
Garfield County20152009No Amendments to IECCnonono
City of Glenwood Springs20092009No Amendments to IECCnonono
Town of New Castle20032009Requires third party checklist, blower door (7 ACH50), CAS test, and ENERGY STAR appliancesnoyesyes
Town of Silt2009nonone
City of Rifle20092009No Amendments to IECC
Town of Carbondale20092009No Amendments to IECCnoyesmaybe
Pitkin County20152015No Amendments to IECCnoyesyes
Town of Basalt20062015noyesyes
Town of Snowmass Village20152015No Amendments to IECCyesyesyes
City of Aspen20152015IECC -many amendmentsnonono
Eagle County20152015Fenestration U-factor .30 max.noyesyes
Town of Vail20152015R21 on wood framed can be substituted for continuous insulationnoyesyes
Town of Avon20152015all gas fired boilers used for snow melt minimum 92% AFUEnoyesyes
Town of Eagle20122012No Amendments to IECCno
Town of Gypsum2003nononeno
San Miguel County20092009San Miguel County Prescriptive Codeif over 5000 sfyesif over 5000 sf
Town of Telluride20032009Eliminated whole code and replaced with their own that has higher insulation levels, required HERS, blower door, and duct blasting, min. HVAC efficiencies, low flow fixtures, and rough for solaryesyesyes
Town of Mountain Village (Telluride)20122012HERS rating required, mechanical engineering required, permit fee reduced for good HERS or low exterior energy useyesyesyes

Aspen no longer a leader in carbon reduction policy

I was hugely disappointed to learn that Aspen no longer seams interested in being viewed as a leader in carbon reduction. The City has just adopted, what is, in my opinion, a relaxed version of the International Energy Conservation Code. The Building Department asked me for data. So I went through 140 different blower door tests and HERS Ratings I had on file to get a feeling for how our new construction is looking. Summary of data below…

locationnumber of testsnumber of tests over 3 ACH50ACH50 averageACH50 lowACH50 High
City of Aspen49263.41.267.08
Pitkin County42203.231.286.37
Snowmass Village874.122.925.71
Town of Carbondale26133.061.165.8

In terms of HERS Ratings- RESNET says the national average score is 61. Colorado had 12,320 (of 206,583) rated homes last year, with an average score of 55. Remember that lower is better when talking about HERS Ratings. Our average HERS Rating score in the Roaring Fork Valley over the past seven years is a 56. So Colorado is better than average nation wide, but the Roaring Fork Valley is behind the state average. Summary of HERS data below…

Number of Ratings in 2016Average HERS Index in 2016
District of Columbia33759
New Hampshire59161
New Jersey3,70461
New Mexico1,14856
New York3,64053
North Carolina13,39766
North Dakota2158
Rhode Island33462
South Carolina7,74068
South Dakota21953
West Virginia12667


Below is a letter sent to the Aspen City Council…

Aspen City Council members,

I intended to speak at the meeting of January 10th but was misinformed about the time and therefore arrived too late. My intention was to recommend denial of the proposed adoption of the 2015 International Energy Conservation Code as amended by the Community Development Department. My preference would be to see the document adopted as written.

My firm, Confluence, has been providing architectural services in the valley for nearly seventeen years. In 2010 the firm began offering energy code compliance services; energy modeling and building testing.

Aspen has adopted a heavily modified version of the code. One that deletes some important tenets of this latest version of the International Building Code. For instance, the requirement for mandatory air infiltration testing has been removed. My professional opinion is that these tests are a valuable check on the condition of the barrier between outside and inside. The data the we have compiled from our work in the valley shows that only about half of that new construction would have passed the 2015 code limits. Research shows us that air sealing is the single least expensive way to reduce the energy consumption of a building.

Aspen’s Climate Action Plan says the community has a goal of reducing greenhouse gas emissions by 80% by 2050. Approximately 32% of Aspen’s emissions come from buildings. If the City were serious about making those goals, then why relax energy conservation building codes at all? Why would the City lowering the bar instead of ensuring that new construction complies with the same code that Pitkin County, the Town of Snowmass Village and Eagle County have adopted?

To me it sounds hypocritical for, Aspen, the home of CORE, the Canary Initiative, Z Green and AREday, not to be doing everything possible to make sure their new construction meets contemporary minimum construction standards.

Final point, it negates the benefits of having an International code system if every jurisdiction completely rewrites the content. It leads to increased confusion, time, money, and potential for mistakes. Why not standardize?

Mark McLain,

Architect & Sustainability Consultant