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LEED for Homes is a rating system that promotes the design and construction of high-performance green homes. A green home uses less energy, water and natural resources; creates less waste; and is healthier and more comfortable for the occupants. Benefits of a LEED home include lower energy and water bills; reduced greenhouse gas emissions; and less exposure to mold, mildew and other indoor toxins. The net cost of owning a LEED home is comparable to that of owning a conventional home.

The REGREEN Guidelines is not a rating system. The developers of these guidelines have dovetailed as much as possible with the content and resources of the LEED for Homes Rating System, but not to the extent that any sort of rating or certification can be applied to green residential remodeling projects completed using these Guidelines. Where applicable, we have referenced standards and certifications used by the LEED for Homes Rating System, including the following:

• Energy ratings – HERS, EPA Energy Star
• Water efficiency criteria – EPA WaterSense
• Material selections – Forest Stewardship Council (FSC) wood certification, GREENGUARD Children and Schools, Green Seal
• Indoor air quality – ASHRAE 62.2

The REGREEN Program and the REGREEN Residential Remodeling Guidelines are about products and process, about synergies and unintended consequences. In green building, it is rarely a single product or building component or a collection of attributes that results in a building’s being labeled “green.” Green building is almost always about how systems work together to reduce environmental impacts. In the REGREEN guidelines, systems thinking and integration are encouraged by the cross-listing of strategies by project and environmental category, as well as by the “potential issues” section. In the electronic version of the REGREEN guidelines, electronic links emphasize the systems nature of green residential remodeling.

Green remodeling is the design and construction of projects that reduce the environmental impacts of remodeling, including energy, water, and materials consumption; waste generation; and harmful emissions, both indoors and out. Although the principles that govern green residential remodeling are shared with all other design and construction projects, more than a few aspects are unique to green remodeling:

• Range of projects. Residential remodeling covers everything from painting a room to refitting a kitchen to gutting a whole house down to the framing and then rebuilding.

• Existing conditions. In new home construction we generally have just the site to consider, but in residential remodeling there are existing conditions that range from room configuration to hazards such as mold, lead, and asbestos.

• Custom work. Whether in design or construction, just about every residential remodeling project is custom, with very little opportunity for the sorts of economies of scale that occur in production building.

• Professional-client relationship. Remodeling professionals almost always have a client; “spec” remodeling projects are rare. The closer relationship with homeowners requires skills and perspectives not generally required for new construction projects.

• Occupants. Remodeling professionals must plan and often conduct their work based on the health, safety and schedules of real people. Even if the work requires that the home be vacated, the timing and duration of such a period must be very carefully orchestrated.

• Sequenced or staged projects. Many residential remodeling projects are phased or sequenced projects (“we want to do the bathroom and then the kitchen”), and this can make for challenging orders of operation in both design and construction, often requiring innovation and improvisation by remodeling professionals.

• Integration. A cornerstone of all types of green building is systems integration, and residential remodeling adds a new dimension to this integration: integrating the old or existing with the new. Those unique aspects of residential remodeling mean that a best-practices guide, rather than a rating program, is appropriate.

In 2007 the National Association of Home Builders (NAHB) and the International Code Council (ICC) partnered to form to establish a much-needed and nationally-recognizable standard definition of what is meant by "Green Building."
A consensus committee was formed to develop this standard in compliance with the requirements of the American National Standards Institute (ANSI). The resulting ANSI approved ICC-700-2008 National Green Building Standard defines green building for single and multifamily homes, residential remodeling projects and site development projects while still allowing for the flexibility required for regionally-appropriate best green practices.

Similar to the NAHB Model Green Homebuilding Guidelines, a builder, remodeler or developer must incorporate a minimum number of features in the following areas: energy, water, and resource efficiency, lot and site development, indoor environmental quality, and home owner education. The more points accrued, the higher the score.

The Standard, however, includes more mandatory items and suggests that higher thresholds be met in several categories. A new threshold - "Emerald" - was added to denote the highest achievement in residential green construction. The following tables highlight the point values required in each area for green buildings and subdivisions.

First published in 2005, the NAHB Model Green Home Building Guidelines were written by a group of builders, researchers, environmental experts, and designers to provide guidance for builders engaged in or interested in green building products and practices for residential design, development, and construction. The Guidelines were also written to serve as a "baseline" so that NAHB members could easily develop local green building programs.

Divided into two parts, the Guidelines cover seven areas, or guiding principles:

• Lot Design;
• Resource Efficiency;
• Energy Efficiency;
• Water Efficiency,
• Indoor Environmental Quality;
• Homeowner Education; and
• Global Impact.

The Guidelines offer three levels of green building- Bronze, Silver, and Gold.

Part One of the Guidelines contains a checklist of all these items; builders navigate through the checklist, assigning point values for each line item completed. At all levels, there is a minimum number of points required for each of the seven guiding principles to ensure that all aspects of green building are addressed to some degree and that there is a balanced, whole-house systems approach. After reaching the point thresholds, an additional 100 points must be achieved by implementing any of the remaining line items.

Part Two is a User Guide that helps explain each concept of the checklist, including intent, how to implement, and additional resources.

The Green Scoring Tool allows scoring a building to the Guidelines (as well as the National Green Building Standard), and includes all of the Checklist items and their respective points from Part One, plus all of the User Guide information from Part Two.

Local green homebuilding program guidelines may be available. Use the Find a Local Program feature to locate local programs and guidelines in your area.

A Passive House is a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. An energy recovery ventilator provides a constant, balanced fresh air supply. The result is an impressive system that not only saves up to 90% of space heating costs, but also provides a uniquely terrific indoor air quality.

A Passive House is a comprehensive system. "Passive" describes well this system's underlying receptivity and retention capacity. Working with natural resources, free solar energy is captured and applied efficiently, instead of relying predominantly on ‘active’ systems to bring a building to ‘zero’ energy. High performance triple-glazed windows, super-insulation, an airtight building shell, limitation of thermal bridging and balanced energy recovery ventilation make possible extraordinary reductions in energy use and carbon emission.

Performance Characteristics

• Airtight building shell ≤ 0.6 ACH @ 50 pascal pressure, measured by blower-door test.
• Annual heat requirement ≤ 15 kWh/m2/year
• Primary Energy ≤ 120 kWh/m2/year

In addition, the following are recommendations, varying with climate:

• Window u-value ≤ 0.8 Watt/m2/K  
• Ventilation system with heat recovery with ≥ 75% efficiency with low electric consumption @  0.45 Wh/m3
• Thermal Bridge Free Construction ≤ 0.01 W/mK

What is a HERS Rating?

A home energy rating involves an analysis of a home’s construction plans and onsite inspections. Based on the home’s plans, the Home Energy Rater uses an energy efficiency software package to perform an energy analysis of the home’s design. This analysis yields a projected, pre-construction HERS Index. Upon completion of the plan review, the rater will work with the builder to identify the energy efficiency improvements needed to ensure the house will meet ENERGY STAR performance guidelines. The rater then conducts onsite inspections, typically including a blower door test (to test the leakiness of the house) and a duct test (to test the leakiness of the ducts). Results of these tests, along with inputs derived from the plan review, are used to generate the HERS Index score for the home.

The HERS Index

The HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home’s HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.

Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus a home with a HERS Index of 85 is 15% more energy efficient than the HERS Reference Home and a home with a HERS Index of 80 is 20% more energy efficient.