Sam Rashkin on ENERGY STAR’s new rules for SIP homes
A recently announced change to the EPA’s ENERGY STAR program states that homes constructed with structural insulated panels (SIPs) on all exterior walls and roofing may choose to bypass a blower door test. Instead, a visual inspection will suffice to verify air infiltration requirements, outlined in a one-page form (see below) and supported by HERS rating documentation. MM spoke with Sam Rashkin, national director of the ENERGY STAR program at EPA, about this change.
Modern Materials: What was the reason for issuing the blower-door test exemption for SIP homes?
Sam Rashkin: There were many reasons. First, homes built with SIP walls and roof are inherently so tight the primary problem is adequate ventilation and not excessive air infiltration. Secondly, damage such as that found in Juneau, Alaska, where roof ridge joints leaked1 could have been avoided with a comprehensive visual inspection. We know air leakage vulnerabilities occur with SIPs at the limited panel joint areas making them conducive to a visual inspection. And lastly, many SIP homes are installed in areas not served by the traditional HERS infrastructure where simpler verification processes would be useful.
MM: What is it about SIP homes that makes you so sure the blower door test isn’t necessary?
SR: SIPs are always an excellent wall system because they inherently include zero-tolerance insulation without any gaps, voids, or compression and very limited leakage areas limited to easily observed panel joint connections. In addition, a SIP house addresses almost all items on the ENERGY STAR Thermal Bypass Checklist because of the six-sided construction assemblies employed.
MM: Not everyone thinks the exemption is a good idea. For example, George James at the DOE’s Building America Program thinks blower tests aren’t that expensive, and you still need them to find hidden leaks.
SR: We understand that there are different points of view. However, all research data supports that SIPs are inherently air-tight. This includes studies at DOE’s own national laboratory, Oak Ridge National Laboratory, and numerous other testing on SIP homes indicating they consistently pass blower door tests well beyond program guidelines. If anyone else has any research data that contradict this existing knowledge, we would love to see it and respond appropriately with our policy. But you shouldn’t protect process for the sake of process.
MM: How do you think builders and homeowners will be affected by the new rule? Where are the gains? SR: The objective of ENERGY STAR is to constantly improve by adding value for builders and consumers. If we don’t, we fail. By simplifying or eliminating processes that don’t add value, we can add other processes that do. For instance, we added the Thermal Bypass Checklist inspection to ENERGY STAR Qualified Homes because this will help redirect the home building industry to thermal envelopes that work. Offering an alternative verification for an advanced wall system such as SIP is a step in this direction.
MM: Is ENERGY STAR considering similar exemptions for other wall systems?
SR: The blower door exemption is just for homes with SIP walls and roofs where the entire thermal envelope is assured to be air tight. Other advanced wall systems that offer the same total envelope solution could also be considered for this exemption, including homes with Insulated Concrete Form (ICF) walls and either SIP or spray foam roofs. However, EPA is not looking for new exemptions, but will consider reasonable requests backed up with good technical data.
MM: As energy-efficiency solutions like SIPs make headway in the market, how is ENERGY STAR keeping up standards so the rating stays meaningful?
SR: EPA actively follows new research and technical developments for opportunities to improve our program requirements. This includes tracking progress with research programs such as DOE’s Building America Program, active involvement with building science conferences and meetings, extensive communication with utility and state sponsored programs, and ongoing coordination with building product manufacturers and associations.
MM: Is the EPA considering a tiered or progressive rating system? Say, “ENERGY STAR Gold” or “ENERGY STAR 2007?”
SR: A large part of EPA’s success with ENERGY STAR is linked to aggressive management of the “brand.” EPA recognizes that energy efficiency is just one of many attributes consumers consider when selecting products. And a home is probably the most overwhelming consumer purchase. We feel, to be effective for mainstream buyers, a brand must be simple and clearly define a consumer benefit. Multiple tiers would complicate the decision and leave much of the interpretation to sales professionals rather than to the EPA. As a result, EPA is committed to keeping ENERGY STAR a binary decision for consumers: either it is, or it is not ENERGY STAR and meets EPA’s and DOE’s strict guidelines for energy efficiency.
NOTE 1 [editor’s note] Rashkin refers to much-publicized reports of water infiltrating six-year old SIP roof structures in the Bellview subdivision of Juneau, Alaska, in 1997. The causes of the failures were manifold, but in part traced to installation error and homeowner lifestyle, such as failure to keep up heat-recovery ventilators.
Sam Rashkin is the national director of ENERGY STAR for Homes. He can be reached at email@example.com.