Boulder County Revamps BuildSmart Program

Having been operating for the last couple of years under what are rumored to be the nation's strictest energy efficiency building codes (which is all wrapped up in the moniker "BuildSmart"), Boulder County has just released a significantly revised BuildSmart program. Three major changes are:

1. The rules have been both simplified and relaxed for additions and remodels.
2. A prescriptive path option is now available whereas previously the performance path (via a HERS rating) was the only option for compliance.
3. The scale for new construction is now somewhat more lenient, and a sliding scale is introduced for homes larger than 3,000 SF. Previously, the required scale went from HERS 60 to 40 to 25 to 10 or below as the house size got larger.

With regards to additions and remodels, a common complaint I have heard has been that the regulations were getting in the way of people making any improvements to their old, inefficient houses since the rules required very high levels of whole-house energy efficiency once certain size thresholds were crossed. The new rules relax these requirements somewhat: any addition or remodel to an existing house that will result in a total conditioned area of 3,000 square feet or below will have to meet a HERS rating of 80 -- a reachable threshold for all but the most derelict of houses, but FAR more efficient than most existing homes. Above 3,000 SF a sliding scale kicks in, raising the required efficiency levels as the house size grows. For example, a 4,000 SF house will need to meet HERS 70, while a 6,000 SF house will need to meet HERS 50 (the lower the HERS score, the more efficient the home). Houses 8,000 SF and above won't need to get lower than HERS 30, which is still a pretty high bar but not as high as it was before.

The prescriptive path is also one of the all-new features of this new BuildSmart program. While the performance path requires that a house be modeled to predict how it will perform then tested to verify that performance, a prescriptive path is essentially a "recipe" that must be followed. So rather than saying that a house must hit a certain HERS score (performance) the prescriptive path says, for example, that you must use at least R-54 insulation in the ceiling, R-42 in the floor, windows with maximum U-value of 0.35, etc. Meet each requirement and you pass, no proof of performance required other than a required insulation inspection and duct test -- the specific requirements are on pages 18 and 19 of the new program document (PDF link).

Finally, the last major change (as I see them) is that the new program both relaxes the current efficiency standard and introduces a sliding scale for required efficiency for new construction. Under the old program, a house 1,001 to 3,000 SF would have to meet a HERS index score of 60. So despite that the 3,000 SF home is three times the size of the 1,001 SF home, they had to meet the same efficiency standard. However, a house that was to be 3,001 to 4,000 SF had to hit HERS 40. Houses larger than 5,001 SF would have to hit HERS 10 or below, a very high threshold. Now, the sliding scale means that a house of, for example, 3,100 SF won't have to meet a HERS index 20 points lower than a house of 2,900 SF; instead, the decrease in the required HERS index is 1 point for each 100 SF in house size increase.

The entire document can be found on the BuildSmart web site, or can be downloaded in PDF directly via this link.