What's the difference between LEED certifications for homes and businesses?

LEED guidelines are structured similarly for both homes and businesses. They separate credit points and prerequisites into several areas of compliance, including water efficiency, indoor environmental quality, site selection, use of materials and resources, and energy use. The difference between the two rating systems shows up in the specific requirements and credit points described in each of those areas, and those variations arise in how homes and businesses are used by their tenants or owners. A business has a lot more people moving around throughout the day, and it uses more energy. A home usually has more outdoor spaces, uses more water per person, and has household appliances that businesses usually don't. So, the differences in the two sets of guidelines reflect those variables.

For example, sustainable site selection is one of the subdivisions of the LEED guidelines. This focuses on making sure that the structure is built in a place where it won't have a negative environmental impact. Businesses are awarded points for reducing light pollution from outdoor lighting, providing underground parking and creating shade that reduces ambient heat in their neighborhoods [source: U.S. Green Building Council]. Businesses also receive credits for locating facilities closer to mass transportation, and for offering onsite bike storage and changing rooms to encourage employees to bike to work [source: U.S. Green Building Council]. None of those improvements apply to residential construction, however homes do get points for maintaining 40 percent of a lot as a "no-disturbance zone" where plants and trees are left alone. Generally, LEED has more guidelines for landscaping when it comes to residential construction, including a ban on "invasive plants" that don't fit with the regional ecosystem and credits for landscaping that resists erosion and drought [source: U.S. Green Building Council].

Water efficiency is another area of LEED certification, and the guidelines establish different priorities for homes and businesses. Businesses are required to meet specific water efficiency standards for all toilets and faucets as prerequisites to certification. Water use for toilets is set at a maximum of 1.6 gallons per flush (gpf), or 1 gpf for urinals. Faucet pressure is capped at .5 gallons per minute [source: U.S. Green Building Council]. Homes can earn credits for water efficiency, but there are no prerequisite usage standards. Instead, LEED for homes has tiered standards -- the more efficient a home's toilets, faucets and washing machines are, the more credits it can receive. LEED guidelines also include credits for homes (but not businesses) that use rainwater harvesting systems, or gray water recycling systems [source: U.S. Green Building Council]. Gray water recycling is the process of reusing water from clothes washers, sink drains and showers [source: Barker].

Energy and atmosphere guidelines set up to improve a LEED building's energy efficiency and reduce its carbon footprint are very different for homes and businesses. Homes are required to meet federal ENERGY STAR standards for home energy use [source: U.S. Green Building Council]. ENERGY STAR standards establish a baseline for energy efficiency for homes, based on a target of 20 to 30 percent improved efficiency over the average home [source: U.S. Environmental Protection Agency]. Exceeding those standards earns a project credit points [source: U.S. Green Building Council].

Since different business facilities use energy in different ways, businesses have to meet a much more detailed and complicated prerequisite requirement called "commissioning." Commissioning involves taking on a professional whose job is to oversee the energy planning for a project to make sure it is designed as efficiently as possible. The process is customized to the specific business, since a factory and an office building have very different energy needs. Businesses also have to meet requirements like using HVAC systems that don't emit harmful CFCs and making sure at least half of all the building's equipment is ENERGY STAR certified [source: U.S. Green Building Council].

LEED guidelines also cover materials and resources used during and after construction. Both businesses and homes are encouraged to reduce waste and recycle any unused materials. They are also required to keep wasted building materials below a maximum level. Commercial buildings have credits available that don't apply to homes. For example, a business facility can claim points if at least 30 percent of the furniture used in the building comes from "salvaged, refurbished or used" sources [source: U.S. Green Building Council].

One of the more offbeat areas of the LEED guidelines is the set of requirements and point credits surrounding indoor environmental quality. Those standards are based around the idea that the health and comfort of the people who use a building is important. The guidelines for homes include credits for systems that control moisture and temperature levels, and keep air clean of contaminants and impurities. In addition to those guidelines, businesses can claim credits for a range of improvements focused more on employee comfort than safety. For example, points are awarded to facilities where 50 percent of workers have access to individual temperature and lighting controls in their workspaces [source: U.S. Green Building Council]. They can also claim credit points for providing a certain amount of sunlight to employees. Credits are even available for designing work areas so that at least 90 percent of employees have a view out the window [source: U.S. Green Building Council].

LEED guidelines are extremely intricate for both businesses and homes. Keep reading for more information on these complex standards.