Using SIPs to Build High-Performance Homes: Lower ACH and HERS for Maximum Efficiency
Hot off the press, Green Builder Magazine’s 12th annual “Green Home of the Year Awards” has once again awarded projects constructed with Premier Building Systems’ Structural Insulated Panels (SIPs). Premier is a go-to for the high-performance home builder, as their acclaimed panels have been supporting energy efficiency for nearly 30 years. Whether using SIPs in extreme climates like Arizona and Alaska, in mild Mediterranean climates like Palo Alto, California, or rain-laden areas such as Anacortes, Washington, builders are proud to build with the high-performing construction material that’s prepared to meet Mother Nature head-on.
Superior ACH ratings with SIPs
While SIPs can help attain LEED certification — the gorgeous Palo Alto Apartments are a case-in-point, as the project gained LEED Platinum certification — the panels also check off other quantifiable high-performance metrics, such as low air changes per hour (ACH) and Home Energy Rating System (HERS) ratings.
ACH, also called the air exchange rate, “can be calculated by multiplying the building’s (cubic feet per minute) CFM by 60, then dividing by the building volume in cubic feet. (CFM x 60)/volume. The requirement is expressed in ACH, which takes account of the overall size (volume) of the home.” To test ACH, independent third parties attach and seal a powerful fan to a door (blower door) to blow air in and out of a building. They then measure the flow rate at a specific test pressure.
The International Energy Conservation Code (IECC) requires that building envelopes have an air leakage rate no higher than five in Climate Zones 1 and 2. For Climate Zones 3 through 8, this number drops down to three. Nearly airtight, SIPs can often lead to air change results of less than 1 ACH50 when put in by an experienced installer. For example, a passive house in Menlo achieved 0.2 ACH50 thanks to the high-performing panels. In the winning Anacortes Triple Zero Home, sealed with Premier SIPs, the air-blower test was just over 1.0 ACH50. With significantly tight buildings, customers save on heating and cooling bills, while enjoying the less tangible aspects of a consistent, comfortable air temperature throughout the home, regardless of being upstairs, downstairs or other areas where one would typically find changes in temperature. Meanwhile, builders pride themselves in knowing they are doing their part to reduce our carbon footprint.
SIPs equal low HERS scores
Another barometer of a home’s energy performance is the HERS Index. This industry standard involves having a certified Home Energy Rater determine a home’s energy efficiency and assign the building a relative performance score. The index compares a “standard” new home to homes which are either more or less energy efficient. Scores below 100 represent homes that are more energy efficient than the standard, while scores greater than 100 are less efficient. A home that is 35% more energy efficient, based on this scoring system, would have a HERS index of 65. The lower the rating, the more energy-efficient the structure. Since exterior walls and roofs factor into a HERS score, building with tight SIPs in these areas and more can contribute to a lower overall index. Less air leakage means a higher-performing home and, consequently, a lower HERS score.
With low HERS ratings, homeowners are a step closer to qualifying for Energy Efficient Mortgages, which recognize the borrowers’ utility savings and added value to the home. Happy customers are proof of a job well done, and builders can take pride in providing homeowner satisfaction with environmentally friendly, high-performing SIP solutions.
Contact an expert Premier Rep today to learn why leading builder Greg Koepf and architect/designer Ted L. Clifton, winners of Green Builder’s prestigious Green Home of the Year Award, trusted Premier with tightness and resiliency for statement homes.