The LEED™ (Leadership in Energy and Environmental Design) green building rating system was originally developed by the U.S. Green Building Council (USGBC) to provide a recognized standard for the construction industry to assess the environmental sustainability of building designs. Canadian Green Building Council (CaGBC) has since adapted the USGBC LEED™ rating system to the specific concerns and requirements of buildings in Canada.
LEED™ is a point-based rating system; points are earned for building attributes considered environmentally beneficial. LEED™ differs from other rating systems in that it has quantified most of the "green credits". For example, 5% of the building materials must be from salvaged materials to earn a point for the salvaged materials credit.
LEED™ 69 points (70 for LEED™ Canada) covering six topic areas. Each topic area has a statement of associated goals.
Site Development: minimize storm water run-off, encourage carpooling and bicycling, increase urban density and green space
Water Efficiency: eliminate site irrigation, reduce water consumption, minimize or treat wastewater
Energy Efficiency:reduce building energy consumption, use renewable energy, eliminate ozone-depleting chemicals, commission building systems
Material Selection:minimize construction waste, re-use existing building facade, use recycled and salvaged materials, use renewable construction materials, design and build more durable buildings
Indoor Environmental Quality: incorporate daylighting, use low-emitting materials, provide operable windows and occupant control of workspace, improve delivery of ventilation air
Innovation in Design: use a LEED Accredited Professional, greatly exceed the requirements of a credit, incorporate innovative environmental features not covered in other areas
Designers can choose the credits most appropriate to their project to achieve a rating. LEED™ has four performance ratings:
Certified: 26 to 32 points
Silver: 33 to 38 points
Gold: 39 to 51 points
Platinum: 52 or more
The LEED™ system can be used in three ways to improve the "greenness" of a building design:
LEED™ can serve as a design guide for the design team. The LEED™ credit system is a systematic way of ensuring that the most important environmental issues are considered during the design of a building.
LEED™ reports are a valuable means of showing the client and other interested parties that the design has effectively addressed environmental issues.
A building design can be certified by the USGBC or CaGBC.
Certification provides increased market exposure and places the building in elite company among the most green buildings in North America. LEED™ registration and certification fees are 4 cents U.S., or 7 cents CDN, per square foot. In addition, LEED™ requires calculations and documentation to validate each LEED™ credit claimed. In many cases, the CBIP energy efficiency incentive is sufficient to cover all the costs of CBIP and LEED™ certification.
LEED™ is the most recognized green building rating system in North America. There are over 200 buildings that have been registered with the CaGBC (over 2000 are registered with the USGBC to become LEED™ certified). Many developers, particularly those working on federal government and leading-edge private sector buildings, are requiring that building designs meet LEED™ Silver performance. Given that conventional new buildings would likely score only a few LEED™ points, achievement of any LEED™ level represents a significant reduction in building environmental impact and improvement of indoor environment.
The Canadian version of LEED™ is similar to the U.S. version with the exception that energy efficiency is relative to the Canadian Model Energy Code for Building (CBIP and the associated program materials requirements reference Canadian building standards. (The CBIP program of Natural Resources Canada provides financial incentives of up to $100,000 to make a building energy efficient.)
While LEED™ has no financial incentives directly attached to it, any building vying for LEED™ Canada certification must meet the stringent requirements of the Natural Resources Canada's Commercial Building Incentive Program (CBIP) - reducing energy consumption by 25% relative to the Model Energy Code for Buildings. CBIP provides financial incentives of up to $60,000 for buildings that meet, or exceed, program requirements.
The larger benefit of LEED™ buildings is an improved indoor environment (lower absenteeism, greater productivity, better thermal comfort), lower maintenance costs (commissioned building, more durable materials, smaller or eliminated building systems), higher corporate profile (increased product sales, marketing advantage, improved employee morale), and reduced risk of remedial measures (to deal with sick building syndrome or environmental contaminants). The table below summarizes typical costs and payback periods for LEED™ buildings. The payback includes only annual utility energy savings.
|Leed™ Points||26 to 32||333 to 38||39 to 51||52 to 69|
|Energy Savings||25 to 35%||35 to 50%||50 to 60%||>60%|
|Annual Utility Savings||$0.75/ft²||$1.00/ft²||$1.25/ft²||$1.50/ft²|
|Typical Payback||Under 3 yrs||3-5 yrs||5-10 yrs||10+ yrs|
|Incremental Construction Cost|
It is possible to improve the environmental "footprint" of existing buildings-a practice known as "greening." The greening of existing buildings requires different approaches and technologies than with new buildings. In most cases, the building structure and systems must remain as is, and sustainability options must fit within these constraints. On the other hand, existing buildings present opportunities for improvement in building operations and occupant behaviour to minimize environmental impact.
Recently, the US Green Building Council released LEED EB (Existing Buildings), an 83-point rating system that assesses the "greenness" of building operations. Britacan is able to help building owners and operators achieve LEED-EB certification.
Greening existing operations begins with an energy audit to reduce energy consumption and a green audit to identify opportunities to reduce operational waste, improve the indoor environment and reduce building environmental impacts. Often, the most cost-effective option is to re-commission the building systems. As buildings age and maintenance staff change, the building systems no longer function as originally intended, and this can result in high energy use, poor air quality and increased maintenance costs. Re-commissioning corrects these problems and ensures that current maintenance staff understands how the building should be operated and maintained.
More comprehensive measures can be implemented during building renovation. As part of the renovations, improvements in the building envelope and mechanical and electrical systems can be easily and cost-effectively implemented. The choice of renovation materials can have a large impact on indoor air quality, durability and maintenance.
Energy audits are the first step in improving the operation of existing buildings. Energy audits identify and determine the economic viability of measures to reduce annual energy costs. An energy audit is the first step in achieving LEED EB certification (LEED for Existing Buildings)
An energy audit consists of four main steps.