There are a variety of ways to lean green or to go totally green. There are just as many types of certifications that quantify greenness. The most popular are:
NAHB Research Center Certified certificate, the homeowner's guarantee that the home was built according to one of the levels of green outlined in either the ICC 700-2008 National Green Building Standard or the NAHB Model Green Home Building Guidelines. The NAHB Research Center is the sole certifier recognized by NAHB's National Green Building Program.
Many of the energy-efficient qualities of a green home are easy to spot. Appliances, windows, and water heating systems will likely have ENERGY STAR® ratings. The home should also include efficient lighting fixtures and bulbs. Renewable energy sources, such as photovoltaic electricity and water heating systems, further decrease the overall energy consumption within the home.
Fixtures and appliances such as low-flow showerheads, faucets, and toilets, and ENERGY STAR® dishwashers and washing machines all conserve water. Programmed, low-volume irrigation systems, rainwater collection systems, wastewater treatment systems, and hot water recirculation systems also save water.
These decisions—from home size, to orientation on the lot, to floor plan layout—are made in the design of your home and development of the lot. The house orientation and design should take advantage of natural daylight to reduce lighting needs, and should use strategies to reduce heat gain in the summer and heat loss in the winter. The home should contain renewable materials, including rapidly-renewable wood species such as bamboo, and recycled-content materials in carpets, tiles, and concrete formulations.
Indoor Air Quality Features
The heating, air conditioning and ventilation system (HVAC) must be appropriately sized for an efficient and properly ventilated home. Fans in the kitchen and bathrooms should cycle fresh air inside, and release stale air. Low-VOC paints and finishes and wall papers should be used as well.
Outside the Home
In a green home, care should be taken to preserve trees and other vegetation native to the area. Landscaping should contain plants that are appropriate for the climate, and grouped according to water needs. Driveways and other impervious surfaces should be reduced as much as possible, and may be composed of gravel, permeable block pavers, grids, or other permeable systems.