Comparing and Contrasting Residential Green-Building Certifications

This online-only article is a supplement to the November/December 2015 print edition of Home Energy Magazine.

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In residential construction—much more than in commercial construction—there are a surprising number of green building rating systems. These systems have different criteria to rate green buildings. This leaves homebuyers, builders, and the general market confused as to which rating system to use.

Before deciding which green-building rating system to choose, you should understand why these systems exist. More and more states and municipalities are adopting energy codes, and many of them are using the International Green Construction Code (IGCC), which covers more than energy efficiency and renewable energy. Builders and designers who commit to green building now are positioning themselves for the time when energy codes are updated in their area.

The state of Michigan is considering using a green-building rating systems to help meet energy code in 2016 for renovations that include energy upgrades. According to a smart market report conducted in 2014 by McGraw-Hill, green residential new- construction will account for 30% of the $100 billion construction industry market by 2018 Surveys show that nine out of ten home buyers are willing to pay a lot more for a home with guaranteed energy savings and a seven-year return on investment. These surveys also show that home buyers place a high value on environmentally friendly features. According to Green Builder Media, “79.8% of consumers say that they would look for a green rating/credential or designation (such as LEED or the NGBS) when buying a new home.”

New incentives and financing are becoming available for home buyers interested in buying a green home. Examples of new incentives include tax abatements in major areas of Ohio for certified green homes, expedited permitting for green registered projects in Chicago, and reduced fees in Indianapolis for green homes. As for new financing, home buyers and developers can now obtain financing by using appraisers who utilize the Appraisal Institute’s addendum for evaluating green homes; and by borrowing from lenders who use green appraisals and energy models to secure the higher up-front costs. (For more on appraisers who value energy efficiency, see “Hidden Benefit of Home Performance,” HE Sept/Oct ’15, p. 18.)

Finally, programs like Property Assessed Clean Energy (PACE) and on-bill financing, where financing for home energy improvements is added on to a consumers energy bill and paid off over time, are available in some areas. The added amount on the consumer’s energy bill is around the same as the cost of the monthly energy savings. This enables homeowners to achieve higher sustainability goals.

Baseline Energy Certification and Rating Systems

Typically, green-building rating systems specify measures in the areas of energy, health, water use, location, and materials. Other energy certification and rating systems address regional priority issues, innovation, reduced electromagnetic loads, accessibility, and climate resiliency. Each rating system uses an energy-modeling program as the backbone of the certification. Cake Systems’ Energy Performance Score is an effective tool for estimating a home’s energy use in kWh per year and has been used on over 20,000 homes in over 20 states. The DOE Home Energy Score has is a similar tool that is equally widely used in existing homes (see “DOE’s Home Energy Score: Looking Back and Forging Ahead,” in this issue).

The largest and most widely recognized rating system is the HERS Index. This tool works best on new construction or major rehabs and is now being used to rate one-third of all new projects in the country. Using a floating HERS, the EPA Energy Star for Homes rating system now goes beyond energy and reviews durability and HVAC commissioning. A water management checklist ensures that the built home controls moisture so that it doesn’t damage a home or create indoor air quality problems. Energy Star for Homes works best with major rehabs, new construction, low-rise multifamily buildings, and four- or five-story buildings with decentralized HVAC systems and water heating. EPA also has two other certifications. These are Indoor Air Plus (IAP), which requires Energy Star 3 (ESV3) as a baseline, and Water Sense for homes, which is a standalone program. The DOE Zero Energy Ready Home program incorporates ESV3, Water Sense, International Energy Conservation Code (IECC) 2012, and a checklist on how to maximize solar gain and PV exposure for the project. It also requires prewiring for renewable energy so the homeowner can add electricity production from renewable energy when the installation is affordable—ideally allowing the home to use net zero energy. And the Passive House certification from the Passive House Institute US requires DOE Zero Energy Ready certification and other prerequisite measures, including modeling very low kBtu per square foot per year, low ACH based on floor area, and other mechanical efficiencies.

National Green Building Standard.

The National Green Building Standard (NGBS) is administered by the Home Innovations Lab, which is associated with the National Association of Home Builders. This four-tiered rating system currently requires that the project be 15–60% beyond IECC 2009 energy code requirements. Builders have the option of using HERS or Energy Star to score energy points. NGBS has fewer prerequisites and more options than most programs. NGBS uses a third-party verifier to inspect the project. This verifier is audited for quality assurance through a desktop paperwork review. NGBS is growing in popularity, with over 50,000 certified homes, and acceptance in many state programs. It is the only green-home-rating system approved by the American National Standards Institute. According to the Home Innovations Lab, NGBS can be used for residential projects of all types and sizes. NGBS is unique in that it is tied to the International Green Construction Code, so a Silver-certified NGBS project meets the IGCC code requirements, making the transition from code to voluntary program very easy.

LEED for Homes.

The LEED certification, delivered by the United States Green Building Council, is the only global residential green-building certification program. Over 60,000 buildings, with over 150,000 residential spaces, are LEED certified. The residential certification began as a pilot in 2005. It is much less widely recognized than the commercial system. Despite the lack of recognition, many residential projects of up to 12 stories are LEED certified. LEED Version 3 requires a HERS index of 70 and the use of the Energy Star Version 2 Thermal Bypass checklist. A LEED midrise project that lacks a decentralized system requires going above ASHREA 90.1 2007 using energy modeling. Beyond that, the LEED system has bare-minimum requirements in every category as well as minimum points needed for certification. LEED has one of the most stringent quality assurance oversight structures. These structures utilize a provider model, a quality assurance director, and third-party green raters. All these help to guarantee that what is on the checklist is actually installed and working. LEED will launch Version 4 in 2016; this new version will reduce paperwork requirements, add a unique water performance pathway, and require Energy Star Version 3 compliance.

Enterprise Green Communities.

The Enterprise Foundation’s Green Communities rating system is designed for developers of affordable housing. New construction and major rehab single-family and low-rise multifamily require a baseline of Energy Star certification. Moderate rehabs do not require Energy Star but do require a HERS of 85; moderate masonry rehabs require only 100, due to the difficulty in adding insulation. This rating system can also be used on mid- and high-rise buildings utilizing that utilize ASHREA 90.1 2010 energy modeling. Green Communities has many more prerequisites than most rating systems. It does not have a tiered award level; it just requires 30–35 extra points above the prerequisites to certify. The Enterprise Foundation has developed a free online work flow/project management tool for green home building that is useful for applying for Green Communities certification. Green Communities certification is free, but it can be very difficult to obtain and organize all the required documentation, especially for teams new to green building. While an energy rater is required on low-rise projects, there is no other third-party on-site inspector reviewing anything but the energy aspects of the building. This rating system is fairly strong in the Midwest, and it is becoming more widely used nationwide, as state-based affordable-housing program incentives start to require it. Some unique aspects of Green Communities 2016 are that it will add net zero energy, beyond-ADA accessibility, and climate resilience strategies.

GreenStar Homes Certification.

The GreenStar Homes Certification system is an expansion of Minnesota’s GreenStar and is now available nationwide. This certification does not have any direct energy requirements, but it has an optional performance pathway utilizing an energy use index from an approved tool such as the ones described above. This helps bring about an energy awareness on the part of homeowners and it can help to normalize energy usage across all climate zones. GreenStar requires minimum credits in each of the five green criteria. It also has basic prerequisites for the entire home, along with prerequisites for areas of the home that you plan to remodel. The biggest benefit of GreenStar is that it is specifically designed for remodels and additions. It helps homeowners and contractors to develop work scopes, bids, specifications, and accountability forms to guide renovation projects. The certification can be used on new construction and multifamily rehabs as well. It is available for free online, and certification is optional. Other unique features of GreenStar are guidance and options for reducing electrical loads and electric and magnetic field radiation, and details on accessibility options for building or remodeling. Unlike the other certifications described in this section, GreenStar is overseen by an organization that is strictly apolitical, and that does not engage in lobbying of any kind.

The Living Building Challenge.

The most recent certification system coming out of the Cascadia Green Building Council and developed by the International Living Future Institute is the Living Building Challenge. The Challenge was first used on small educational or demonstration facilities, but it is now being used worldwide on many types of residential construction. To receive Challenge certification, the home must produce net positive energy at least 5% over what it uses in a given year, and must be able to maintain power during a short blackout, such as one week. The home must also use only as much water as it captures on-site, and it will be tested for performance based on indoor air quality after construction. Other unique aspects of the Challenge include ratings on net positive waste, beauty, social justice, accessibility, and carbon and land use offsets. Other ratings are based on the location of the home; urban, suburban, and rural homes each have a few different requirements, benefits, and restrictions. The ultimate goal of this certification is to help reduce the barriers to sustainable living. These barriers include ingrained beliefs, code restrictions, use of unsustainable products, and anything that serves as a barrier to authentic restorative design and construction practices.

Which Rating System Is Best for You?

At the GreenHome Institute we encourage you to research each rating system to determine which one is best for you and your clients. Each of these rating systems provides free tools and guidance. Talk with your clients to determine which one makes the most sense to them. All that we ask is that you consider taking the step to become a beyond-code builder, rater, designer or remodeler—and start using these tools to help you take that next step.

Brett Little is the executive director of the GreenHome Institute, which offers training and support for designers, builders, and contactors who work on single- and multifamily residential new construction and in existing buildings.

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