Big changes are brewing in the Energy Star for Homes program. The U.S. Environmental Protection Agency (EPA) released a third version of the popular Energy Star for Homes standards to keep pace with more rigorous energy codes and the plethora of new energy-efficient technologies entering the marketplace. Energy Star 2011 is the EPA’s newest iteration of their elective standard for energy-efficient homes.
The new program requirements will go into effect on January 1, 2011 for single family homes in an abridged form labeled Version 2.5, in order to give the building industry adequate time to adjust to the new standards. Version 2.5 is nearly identical to Energy Star 2011, with the exception that only the Air Sealing and Air Barrier sections of the new Thermal Enclosure Checklist (see below) will be enforced. All other visual inspection checklists will be used but not enforced until 2012.
New Checklists
Several additional visual checklists will be added for the HERS rater to confirm along with the HERS Index requirements. They include a ramped up version of the Thermal Bypass Checklist, now called the Thermal Enclosure Checklist, plus new checklists for Water-Managed Construction and HVAC.
The new Thermal Enclosure Checklist requires that builders install an air barrier that is fully aligned with the insulation and take steps to reduce thermal bridging. The EPA’s Energy Star for Homes Director Sam Rashkin claims this will be a huge benefit for the SIP industry because it requires that other building systems undergo additional measures to meet the whole-wall insulating and air sealing benefits inherent in SIP construction.
“No matter what thermal envelope system is chosen by a builder, it is required to match or approximate the inherent advantages of an advanced wall system such as SIPs,” writes Rashkin, in an address to the SIP Industry. “As a result, the SIP industry will be able to offer all ENERGY STAR builder partners a turn-key solution for meeting the new ENERGY STAR Qualified Homes 2011 requirements.”
HERS Index Target
For many builders, the most significant change will be the move from the current fixed HERS Index threshold to a variable HERS Index Target. Similar to the current guidelines, Energy Star 2011 will offer a prescriptive and a performance option for meeting the program requirements. Whereas builders taking the performance path under the current program are held to a fixed minimum HERS Index (85 for most of the U.S., and 80 in colder climates), the proposed revisions deliver a specific HERS Index Target for each individual home.
To determine the HERS Index Target, the energy rater will use RESNET accredited energy modeling software to theoretically add the energy-efficient measures from the Energy Star prescriptive requirements to the home that is being rated. The resulting HERS Index will be the target that the home must meet or exceed to qualify under the performance path.
The EPA’s rationale for this new system is that it will deliver a more accurate energy-efficiency requirement that reflects the home’s orientation, fuel type, number of stories, and other factors that are not accounted for in a static HERS Index threshold. Solar and other onsite generation systems will not count towards reaching the HERS Index Target.
The HERS Index Target also accommodates variations in state energy codes. Should a local energy code be more rigorous than the Energy Star requirements, the local code will used to determine the HERS Index Target.
Home size adjustment
Large homes are subject to an additional size adjustment factor that will lower the HERS Index Target (the lower the HERS Index, the more efficient the home) to compensate for the higher carbon footprint of a larger home. The EPA defines large homes as those exceeding the size of the average “Benchmark” home as described in the table below. Homes larger than the Benchmark can use renewable energy to towards reaching the HERS Index Target, but only for the incremental change derived from the size adjustment.
Visit Energy Star for Homes for more information on the 2011 program requirements.
