Whether you are looking to buy or build a green home you may quickly realize that the word “green” has many meanings. It could be a home that saves energy or is energy conscious in its design, or it could be a home made from recycled materials. It could also be a home with a rainwater harvesting system or designed with a low-water use landscape. But what about other green or sustainable factors such as net zero energy usage, non-toxic high performing building materials or passive design?
Although it isn’t always easy to do an apples-to-apples comparison between green homes, there are many green building certification programs that can help you understand what, exactly, makes a home green. Below are some of the most common and current green building certification programs in the US. It is important to note that while you may see similarities between these programs, some of these certification programs are proprietary, and cannot be duplicated. Therefore you won’t necessarily see the same checklist or qualifiers from program to program.
Perhaps one of the most recognizable names in green building is LEED, which stands for Leadership in Energy and Environmental Design, and was started in 1998 under the umbrella of the U.S. Green Building Council. LEED is known for certifying commercial and residential buildings, homes and neighborhoods. There are varying levels or degrees of LEED certification: Certified, Silver, Gold and Platinum. Like most certification programs, a building or home must pay for the assessment and their website is full of reference material and guidelines for accreditation. LEED certified homes focus on energy savings and indoor air quality, with an emphasis on a highly functional but efficient building design. One of the more commonly criticized aspects to LEED certification is that the certification process is granted upfront, and there is no follow up certification to ensure that the home is performing efficiently after being lived in for a period of time. LEED is very often used with new building and land development of large multi-family homes or commercial projects. There is an emphasis on ecological and environmental design and conservation, as well as walkability scores.
Energy Star Rating
An EnergyStar certified home is one that has been built with an EnergyStar partner and independently verified. EnergyStar began rating homes for energy efficiency in 1995 and over the years has increased their standards as well as their measuring. In order for a home to be EnergyStar rated, it must adhere to the strict guidelines of the Environmental Protection Agency (EPA), and include the following:
- A complete thermal enclosure system: comprehensive air sealing, properly installed insulation, and high-performance windows work together to enhance comfort, improve durability, reduce maintenance costs, and lower monthly utility bills
- A complete heating and cooling system: high-efficiency systems that are engineered and installed to deliver more comfort, better moisture control, improved indoor air quality, and quieter operation
- A complete water management system: a comprehensive package of best building practices and materials protects roofs, walls and foundations from water damage, provides added protection, and reduces the risk of indoor air quality problems
- Energy-efficient lighting and appliances: EnergyStar certified lighting, appliances, and fans are commonly installed throughout EnergyStar certified homes, helping to reduce monthly utility bills, while providing high-quality performance
Founded in 1990 and based in Germany, the Passive House Institute is an independent research organization that offers a certification program for buildings and homes. The premise of a passive house is a home that doesn’t leak air, and therefor uses very little energy to heat or cool the indoor spaces. In fact, heat loss should be so minimal that little or no additional heating (aside from the sun) should be needed. This type of efficiency is created through better building techniques and insulation but not advanced technology, so this building should be simple to operate and user-friendly. Here are some other facts about passive homes:
- It employs continuous insulation through its entire envelope without any thermal bridging
- The building envelope is extremely airtight, preventing infiltration of outside air and loss of conditioned air
- It employs high-performance windows (typically triple-paned) and doors
- It uses some form of balanced heat- and moisture-recovery ventilation and uses a minimal space conditioning system
- Solar gain is managed to exploit the sun’s energy for heating purposes and to minimize it in cooling seasons
Despite the air-tight design, passive homes are known for being very well ventilated and having excellent indoor air quality. One of the most celebrated attributes of a passive home is that comfort (as in temperature comfort) is ideal. But homeowners should be aware that they may need to purchase appliances and fixtures, like fireplace inserts or ventilation hoods, that comply with the passive home features. Because passive house design relies upon natural heat sources (like the sun), the specific regional climate may influence the exact design of the home.
International Living Future Institute
The International Living Future Institute is an organization whose aim is to certify the sustainability of a building, both residential and commercial. They envision a much broader realm of sustainability and green building, and aim for net-positive performance for buildings. Beyond the specific performance of a structure, they believe in the importance of health, for the people who constructed the building as well as the health and well-being of those who occupy the building. How that building interacts with the surrounding environment are equally important. So not only is the building constructed in an energy efficient manner, non-toxic materials are a requirement (in fact they have a published Red List of 21 banned chemicals that cannot be used). Attention is given to the interaction of the building to the occupants, like how this Seattle building included a wetland area to invite nature into the city and a fully equipped bicycle center to encourage bike transportation. The certification process is more involved and is actually a two-part process (the final audit is actually completed after 12 months of occupancy). They have created a number of organizations that are helping to revolutionize the building and construction process. Their organization has been endorsed by the US Green Building Council.
- Living Building Certification This certification verifies a structures ability to be resiliency, regeneration, equity, community, materials transparency, living future. “Living Buildings™ are intended to be examples of the highest level of environmental performance currently possible.”
- Net Zero Energy Building Certification (NZEB), the only program in the world that independently certifies a net zero energy building performance. The importance of an NZEB certification is based on actual performance, not simulation reports or projections. Not allowed in an NZEB home is the combustion of fossil fuels or nuclear energy, neither of which are renewable.
- Just: Social justice label for organizations that encourages companies to be transparent about their ethical treatment of employees as well as their investments
- Declare: Materials “nutrition” label, maintains a Red List of harmful and hazardous chemicals that should be kept out of buildings
- Reveal: Energy efficiency label for buildings
NGBS – National Green Building Standard
Another well-recognized certification organization is NGBS, which is independently certified by Home Innovation Research Labs, a 50-year old organization. The NGBS certification is focused on performance of a home or building and considers the following:
- site design
- resource efficiency
- water efficiency
- energy efficiency
- indoor environmental quality
- building operation and maintenance
The NGBS is the only residential green building rating system approved by ANSI as an American National Standard. Like many other green building certification programs, this one focuses on creating a home that is healthy, has lower operating costs, and promotes sustainability through design such as walkability and responsible land development.
Is building a green home more expensive?
There tends to be a misnomer in the green building industry that constructing a sustainable, energy efficient or net zero energy home is more expensive than building a traditional home. That is simply not true. Some green homes are custom built, and therefore may have some of the higher costs associated with any custom home. But there are plenty of opportunities to make green decisions along the construction path like choosing eco-friendly or locally sourced materials, installing EnergyStar rated appliances or utilizing geo-thermal energy. Some cities even have a fast-track for green building permits to encourage these types of projects. Keep in mind that green building techniques aim to save money in the long run by designing a high-performance home, so electrical, gas and water costs should be lower than average. Some cities even offer significant rebate or tax incentives, which can further reduce overall operational costs. It’s important that you turn to the expert advice of a green builder, contractor or architect. They will be knowledgeable about various certification programs, will know how to find green building materials, and can help get you the home you want. For an insider’s look at what it means to build and live in a net-zero home, check out this one constructed for $114 per square foot.