Over its entire life cycle, a building has tremendous impact on the environment. Natural resources such as ground cover, forests, water, and energy are depleted to give way to buildings. So by itself, a building can be a hazard to the environment as a whole. However, a Green Building, also known as green construction or sustainable building, is
One that is created using processes and materials that are environmentally responsible and resource-efficient. This practice expands and complements the classical building design concerns of economy, utility, durability, and comfort.

The purpose of a green building design is to minimize the demand on non-renewable resources, maximize the utilization efficiency of these resources, and maximize the reuse, recycling, and utilization of renewable resources.

In summary, the following aspects of a building design are looked into in an integrated way while constructing a green building:

• Site planning
• Building envelope design
• Building system design ((HVAC) heating ventilation and air conditioning, lighting, electrical, and water heating).
• Integration of renewable energy sources to generate energy onsite.
•  Water and waste management.
• Selection of ecologically sustainable materials (with high recycled content, rapidly renewable resources with low emission potential, etc.).
• Indoor environmental quality (maintenance of indoor thermal & visual comfort and air quality).

Elements of Green Buildings

1. Site Planning

• Start by selecting a site well suited to take advantage of mass transit.  
• Protect and retain existing landscaping and natural elements. Select plants that have low water and pesticide needs, and generate minimum plant trimmings. Use compost and mulches to save water and time.
• Recycled content paving materials, furnishings, and mulches help close the recycling loop.

2. Design

Energy-efficient buildings have efficient components and systems that are properly designed and sized and are actively managed once occupied. It is important to make sure that these investments are not subverted in the name of green design or value engineering.

Energy-efficient design strategies encompass a wide range of traditional building construction elements, including building envelope design, mechanical systems, HVAC, lighting, controls systems, and so on.

A project may spend green funds on a few solar panels at the expense of better window glazing, which dollar-for-dollar yields far greater energy savings and pollution prevention.

3. Energy Efficiency

• Passive design strategies can dramatically affect building energy performance. These measures include building shape and orientation, passive solar design, and the use of natural lighting.  
• Develop strategies to provide natural lighting. Studies have shown that it has a positive impact on productivity and well being.
•  Install high-efficiency lighting systems with advanced lighting controls. Include motion sensors tied to dimmable lighting controls. Task lighting reduces general overhead light levels.
• Use a properly sized and energy-efficient heat/cooling system in conjunction with a thermally efficient building shell. Maximize light colors for roofing and wall finish materials; install high R-value wall and ceiling insulation; and use minimal glass on east and west exposures.
• Minimize the electric loads from lighting, equipment, and appliances.
• Consider alternative energy sources such as photovoltaic’s and fuel cells that are now available in new products and applications. Renewable energy sources provide a great symbol of emerging technologies for the future.
• Computer modeling is an extremely useful tool in optimizing design of electrical and mechanical systems and the building shell.

4. Water Efficiency

• Design for dual plumbing to use recycled water for toilet flushing or a gray water system that recovers rainwater or other nonpotable water for site irrigation.
• Minimize wastewater by using ultra low-flush toilets, low-flow shower heads, and other water conserving fixtures.
• Use recirculating systems for centralized hot water distribution.
• Install point-of-use hot water heating systems for more distant locations.
• Use a water budget approach that schedules irrigation using the California Irrigation Management Information System data for landscaping.
• Meter the landscape separately from buildings. Use micro-irrigation (which excludes sprinklers and high-pressure sprayers) to supply water in nonturf areas.
• Use state-of-the-art irrigation controllers and self-closing nozzles on hoses.

5. Waste Reduction

Green architecture also seeks to reduce waste of energy, water and materials used during construction. For example, in California nearly 60% of the state's waste comes from commercial buildings. During the construction phase, one goal should be to reduce the amount of material going to landfills. Well-designed buildings also help reduce the amount of waste generated by the occupants as well, by providing on-site solutions such as compost bins to reduce matter going to landfills.

To reduce the impact on wells or water treatment plants, several options exist. "Greywater", wastewater from sources such as dishwashing or washing machines, can be used for subsurface irrigation, or if treated, for non-potable purposes, e.g., to flush toilets and wash cars. Rainwater collectors are used for similar purposes.

Centralized wastewater treatment systems can be costly and use a lot of energy. An alternative to this process is converting waste and wastewater into fertilizer, which avoids these costs and shows other benefits. By collecting human waste at the source and running it to a semi-centralized biogas plant with other biological waste, liquid fertilizer can be produced. This concept was demonstrated by a settlement in Lubeck Germany in the late 1990s. Practices like these provide soil with organic nutrients and create carbon sinks that remove carbon dioxide from the atmosphere, offsetting greenhouse gas emission. Producing artificial fertilizer is also more costly in energy than this process

6. Materials Efficiency

• Select sustainable construction materials and products by evaluating several characteristics such as reused and recycled content, zero or low off gassing of harmful air emissions, zero or low toxicity, sustainably harvested materials, high recyclability, durability, longevity, and local production.  Such products promote resource conservation and efficiency.  Using recycled-content products also helps develop markets for recycled materials that are being diverted from California's landfills, as mandated by the Integrated Waste Management Act.
• Use dimensional planning and other material efficiency strategies.  These strategies reduce the amount of building materials needed and cut construction costs.   For example, design rooms on 4-foot multiples to conform to standard-sized wallboard and plywood sheets.  
• Reuse and recycle construction and demolition materials.  For example, using inert demolition materials as a base course for a parking lot keeps materials out of landfills and costs less.  
• Require plans for managing materials through deconstruction, demolition, and construction.  
• Design with adequate space to facilitate recycling collection and to incorporate a solid waste management program that prevents waste generation.

7. Indoor Environment Quality Enhancement

The Indoor Environmental Quality (IEQ) category in LEED standards, one of the five environmental categories, was created to provide comfort, well-being, and productivity of occupants. The LEED IEQ category addresses design and construction guidelines especially: indoor air quality (IAQ), thermal quality, and lighting quality.[22]
Indoor Air Quality seeks to reduce volatile organic compounds, or VOC's, such as microbial contaminants. Buildings rely on a properly designed HVAC system to provide adequate ventilation and air filtration as well as isolate operations (kitchens, dry cleaners, etc.) from other occupancies.

During the design and construction process choosing construction materials and interior finish products with zero or low emissions will improve IAQ. Many building materials and cleaning/maintenance products emit toxic gases, such as VOC's and formaldehyde. These gases can have a detrimental impact on occupants' health and productivity as well. Avoiding these products will increase a building's IEQ.

Personal temperature and airflow control over the HVAC system coupled with a properly designed building envelope will also aid in increasing a building's thermal quality. Creating a high performance luminous environment through the careful integration of natural and artificial light sources will improve on the lighting quality of a structure.

Environmental Benefits

• A green building presumably provides short as well as long term savings for the organization. According to the surveys from corporate market report operating costs decreases 8-9% while building value increase 7-8% where ROI value improves 6-7% for green buildings. These drivers also impact the occupancy rate for the overall building up to 4%.
• The tangible savings especially come from areas such as reduction in energy use, CO2 emission, water use and solid waste which help us to calculate and to measure the advantages of green building. Other than tangible savings, there are also intangible savings that green building provides.
• Higher revenue due to higher rents and occupancy rates. Vacancy rates of green buildings are lower than existing buildings. The CoStar Group found that LEED-certified buildings occupancy rate is 92 percent versus 87 percent for traditional buildings.
• Lower operating costs by reducing waste output and energy consumption. The Environmental Protection Agency found that green buildings with a recycling focus can reduce waste output by 90 percent and use 30 percent less energy, which equates to a five percent increase in net operating income.
• Attract and retain quality tenants. Improved indoor air quality in green buildings result in reduced absenteeism, and possibly higher productivity that could increase sales. Green buildings also make it possible to have government tenants.
• Better insurance risk. Green buildings suffer fewer losses and are safer to insure because of the commissioning process required to become LEED certified.

Economic Benefits

A green building may cost more upfront, but saves through lower operating costs over the life of the building. The green building approach applies a project life cycle cost analysis for determining the appropriate up-front expenditure.  This analytical method calculates costs over the useful life of the asset.

These and other cost savings can only be fully realized when they are incorporated at the project's conceptual design phase with the assistance of an integrated team of professionals. The integrated systems approach ensures that the building is designed as one system rather than a collection of stand-alone systems.

Some benefits, such as improving occupant health, comfort, productivity, reducing pollution and landfill waste are not easily quantified. Consequently, they are not adequately considered in cost analysis. For this reason, consider setting aside a small portion of the building budget to cover differential costs associated with less tangible green building benefits or to cover the cost of researching and analyzing green building options.