With buildings accounting for nearly 40 percent of global energy consumption, the building sector should play a key role in effective climate policy. Efficiency measures in new and existing buildings provide an enormous opportunity for countries to reduce their energy intensities while simultaneously driving improvements in public health, labor productivity, and job creation. According to the International Energy Agency, energy efficiency measures have the potential to deliver two-thirds of the energy-related CO₂ emissions reductions needed to achieve climate protection.

Green building is the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle from siting to design, construction, operation, maintenance, renovation and deconstruction.

This practice expands and complements the classical building design concerns of economy, utility, durability, and comfort. Green building is also known as a sustainable or high performance building.

What makes a building green?

In the U.S. real estate market there are a  number of green building rating systems and guidelines currently competing to provide the definitive answer to this question. Of these, the most widely recognized program is the U.S. Green Building Council's Leadership in Energy & Environmental Design (LEED) certification. Other programs include Green Globes, administered by the Green Building Inititative, and the Federal Sustainable Buildings Principles.

Most green building certification systems rate the "greenness" of buildings by awarding points for clearly-defined, environmentally preferable construction, design and systems. These attributes include a range of factors in addition to energy efficiency: choice of materials and location, indoor air quality, water usage, emissions, etc.. Most systems offer tiered levels of recognition, such as Gold, Platinum, 3 Globes, 4 Gloves, and so om, depending upon the number of points a building earns.

Green rating systems differ in their definition and weighting of the various environmental attributes, their means for assigning points, and their certification process. Additionally, these rating systems have varying minimum requirements, relationships to building codes, certification processes and costs and certifier training requirements.

What Are the Economic Benefits of Green Buildings?

A green building may cost more up front, 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.

Even with a tight budget, many green building measures can be incorporated with minimal or zero increased up-front costs and they can yield enormous savings.

Built Environment: Tools and Resources

Rocky Mountain Institute is a great resource for all things related to energy efficiency and sustainability. They have an excellent list of tools and resources for improving resource efficiency in built environment. Since new tools are constantly emerging, they recommend to periodically return to the page or follow them on twitter.