ABC green home front - building envelope

What is Zero Net Energy Certified

All of the green building code programs differ, but the ABC Green Home will seek to satisfy them all.

A goal of the California Energy Commission is to achieve “zero-net-energy” performance with new residential construction by 2020. Over the past few years, the residential new construction industry has made tremendous progress in constructing higher performance homes, achieving exceptional levels of energy efficiency.

This article provides a forward-looking perspective on the “Certifiable” nature of the ABC Green Home, defined to be a virtual “net-zero energy” model. The certification process generally requires three significant phases, encompassing pre-construction, construction and post-construction stages, though this varies somewhat by program.First, one conducts an objective plan review and evaluation – including a review and discussion point-by-point of the preliminary checklist – through a collective Design Review Charrette. Key team members include the architect, landscape architect and Title 24 consultant, as well as the owner or builder. Next, field observations and documentation at different stages of construction are required. These typically involve at least two separate field reviews at rough and final stages of construction.Finally, field testing and performance verification by a HERS rater is also frequently necessary for a home to be certified.It’s important to remember that Green Raters (LEED for Homes) and Green Point Raters (Built It Green) who are directly responsible for the certifications cannot be engaged in the design or construction process, nor can they have a financial stake in the project.

Evaluation criteria vary with the green building programs offering the certification.We will consider several such programs:Cal Green, Build It Green, California Advanced Homes Program, ENERGY STAR, NAHB Green and LEED for Homes.Of course there are many more, including Earth Craft, Environments for Living, Passive House, Green Globes, etc.Each of these programs has optional levels of “greenness” which builders can pursue.While important differences exist between the primary targeted programs, many share a common DNA of at least five green building elements.The five minimum elements include: 1) sustainable site conditions, 2) energy efficiency, 3) water efficiency, 4) materials and resources, and 5) indoor air quality.Some have a specific focus on energy efficiency alone, such as the California Advanced Homes Program and ENERGY STAR.

CalGreen is the first comprehensive Green Building Code enacted in the U.S., and became effective statewide in January 2011. It has a number of basic mandatory provisions that serve as the code minimum requirements. Green Raters and Green Point Raters call these program The key for success with Build It Green and other similar pointsoriented programs is to start early and engage the various design team members with the owner, general contractor and major rough trades, in an interactive Design Charrette. Green Home Project Partner: Certification A C B www.GREENHOMEBUILDERMAG.com 69 elements “Pre-requisites.” Cal Green also provides optional Tier 1 and Tier 2 levels of performance should builders wish to pursue “greener” building practices. An important difference between the three levels will affect the energy efficiency of The ABC Green Home.

Code minimum requires compliance with the California Energy Commission’s 2008 energy efficiency provisions (Part 6, Title 24). The most recent changes took effect on January 1, 2010. Tier 1 raises the bar, with a pre-requisite of energy efficiency performance which is 15 percent above that standard. Tier 2 further raises the bar to a level 30 percent above that standard. Twelve other prerequisites and five elective measures are required for Tier 1 and Tier 2. Higher performance standards in Tier 2 are all organized around the five elements. These encompass planning and design, energy efficiency, water efficiency and conservation, material conservation and resource efficiency, and environmental quality. Please note that the measures necessary to achieve Tier 2 status could vary by project location. In striving toward the higher standards of Tier 1 and 2, the builder’s costs will vary accordingly.

Build It Green is a California-based nonprofit organization dedicated to promoting green building in California, which pre-dates the new Cal Green Code. Like others, the Build It Green program relies upon a pointbased system, “Green Point Rated,” which has many similar features as CALGreen. Although CALGreen measures do not earn points in the GreenPoint Rated program, Build It Green has included the mandatory CALGreen Code measures in their manual and checklists for the convenience of local jurisdictions and building professionals. Build It Green also relies upon independent plan and field verifications by third party raters, encompassing an extensive matrix checklist of many items organized within the five categories, and broken out by functional disciplines. These disciplines include: site, foundation, landscaping, structural frame and building envelope, exterior finish, insulation, plumbing, HVAC, renewable energy, building performance, finishes, flooring, appliances and lighting. In addition, “Innovation Measures” are recognized and encouraged relative to in-fill sites, cluster home developments, home sizing, subdivision layout and orientation to improve natural cooling and passive solar attributes, design for walking and bicycling, design for safety and social gathering and design for diverse households.

The key for success with Build It Green and other similar points-oriented programs is to start early and engage the various design team members with the owner, general contractor and major rough trades, in an interactive Design Charrette. Formally defined, this Design Charrette process is a series of intensive, hands-on workshops that brings people from different disciplines and backgrounds together to explore various design options for enhancing the final design solution.

This green building program was created by the Investor-Owned Utilities (IOUs) as directed by the California Public Utilities Commission (CPUC). The primary goals of California Advanced Homes are for “50 percent of the residential new construction to be built at least 20 percent better than the 2008 Title 24 Energy Code and 10 percent of the residential new construction to be built at least 40 percent better” than this code. As such, this is an energy focused green building program with financial incentives to encourage builder participation. The project sponsor must contract with a Certified Energy Plans Examiner (CEPE) and a HERS rater for appropriate plan analysis, building envelope testing and performance evaluations. The single advantage of this program is the economic incentives available from the utilities, which are expected to continue until December 31, 2015.

The “ENERGY STAR for New Homes Program” requires a Partnership Agreement between the builder and the EPA (Environmental Protection Agency). Builders must construct one ENERGY STAR qualified home every 12 months to stay in the program. This program is clearly energy focused, but the EPA has related green building program elements rolling out such as “Water Sense” (addressing indoor and outdoor water efficiency) and their “Indoor Air Package.” The advantage for the ABC Green Home to participate in the ENERGY STAR program is the great brand recognition nationally. That said, there are stringent pre-requisites to enroll and participate. For example, builders must submit their detailed architectural plans to a Home Energy Rater (HERs rater) for review and analysis. A prescriptive package of energy improvements developed by EPA helps facilitate this review process.

The “Thermal Bypass Inspection Checklist” must be completed to earn the ENERGY STAR label. Quality Insulation Installation (QII) is yet another program requirement of ENERGY STAR. Examples of items requiring visual inspection during the construction process include framing, proper insulation, and continuous air and thermal barriers to confirm there are no gaps or voids which would compromise the energy performance of the completed home.

The energy performance of the home is field verified by HERs raters using blower door and duct blasting equipment to measure leakage in the building envelope and within the HVAC ducting system. Upon passing these tests and verifications, the home can earn the ENERGY STAR label. We anticipate that the ABC Green Home could achieve the ENERGY STAR label.

Through their research arm, the National Association of Home Builders (NAHB) Research Center, has created a points-based green rating system which meets the criteria of the ICC 700-2008 National Green Building Standard (NGBS). This program establishes design and construction practices for a variety of new and renovated residential homes and communities. There are four green certification levels -Bronze, Silver, Gold and Emerald. Verifications and certifications are by third party NAHB accredited inspectors called Verifiers.

An interesting element of the NAHB program is that home size drives the point scales. For example, a given level of certification has fewer points required for homes of 2,500 square feet or less. More points are required for that same level of certification for houses over 4,000 square feet. Also, similar to the LEED for Homes program, energy certification can be pursued through either a “Prescriptive Path” or “Performance Path.” “The Prescriptive Path lists specific strategies and level of performance of strategies that have to be attained in order for the building to reach the successively higher tiers of certification. The Performance Path describes how well the whole building must perform.” There is a software-modeled minimum energy performance, but no requirement of a site-tested minimum energy performance level. Also, like LEED for Homes, the NGBS program has many points and credits organized by climate zone as defined by the International Energy Code Council (IECC).

The U.S. Green Building Council (USGBC) created a family of green building programs, including LEED for Homes. As one of the first created, this program is one of the most widely recognized nationally. It was developed as a comprehensive program focused on the top 25 percent of green home builders. Within California, Davis Energy Group (DEG) is the LEED for Homes Provider. DEG is a mechanical engineering and consulting firm that works with builders to achieve higher sustainability and efficiency for their housing projects. The Provider reviews and approves all Green Rater project submittals prior to forwarding them on to the USGBC for final on-line project certification. Like the other green building programs, LEED for Homes has prerequisites and electives. ENERGY STAR is one of 18 such pre-requisites. As such, there are the same fees for ENERGY STAR, but also additional fees to register in the LEED for Homes program. In addition, it has eight program elements: 1) Innovation and Design, 2) Location and Linkages, 3) Sustainable Sites, 4) Water Efficiency, 5) Energy and Atmosphere, 6) Material and Resources, 7) Indoor Environmental Quality, and 8) Awareness and Education. Regarding item number five, LEED for Homes recognizes two energy efficiency levels: 1) ENERGY STAR for Homes; and, 2) Exceptional Energy Performance (15 percent above Title 24). Within the LEED for Homes program, there are four performance levels, including certified, “Silver,” “Gold” and “Platinum.” Each of the four has increasingly stringent requirements to achieve and costs will vary accordingly. Builders and project sponsors should also consider the value of dual branding. For example, through DEG, a number of builders are enrolled in both LEED for Homes and Build It Green – taking advantage of dual branding program to enhance the marketing appeal of their homes. The ABC Green Home will aim to be certifiable in all of the above programs.

Don Neff is president and CEO of La Jolla
Pacific Ltd. He may be contacted at
don@lajollapacificltd.com.