For the past two weeks, we’ve covered the basics of the Leadership in Energy and Environmental Design (LEED) building program; it is a certification process to promote green building practices in residential, commercial, retail and service buildings. LEED standards can apply to both new projects and existing structures, and each building is assigned a rating based on how well it follows the guidelines. Last week we looked at what’s necessary to certify your residential home with LEED; this week, we’ll tackle the more complex requirements for commercial spaces. LEED has several different rating systems for commercial structures; they are designed to accommodate the complexities of commercial buildings, and work hand in hand to ensure green practices across a building’s lifetime.

Across all of these varying LEED systems, the main components are consistent: the structure is rated by a certified USGBC member, who assigns points in five different categories (Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, and Indoor Environmental Quality). The details of each category can be found in our first blog post here.

LEED Core and Shell
When a residential home is built from scratch, it’s often a single process from design to construction. Some large buildings are constructed with one or two specific occupants in mind; in this case, the LEED for New Construction guidelines are the most appropriate. However, the speculative development market for commercial buildings is a different story; one developer may oversee the core mechanical components of the building at large, but leave the design of each interior space to the tenants. It’s difficult to know if your building will house a medical lab, a consulting firm, or both. LEED for Core & Shell applies to the main components of a speculative development project, where the developers will not be occupying a significant portion of the new construction.

Core & Shell requires a pre-certification application process, which gives the owners a chance to attract potential tenants to a LEED building. Developers must also take into account the potential occupancy of the building, which is important when calculating water use and parking capacity. The development team must do some extensive modeling tests for energy efficiency, taking into account the different potential tenants and what percentage of the space they will use.

LEED Commercial Interiors
Once the development is finished, a tenant can outfit their space to meet the requirements of LEED for Commercial Interiors, picking up where Core & Shell leaves off. Commercial tenants do not have control over the fundamental parts of their building, such as the HVAC system or the insulation materials. However, they can optimize their space in other ways: they can install high-efficiency lights, use Energy Star qualified appliances, and use environmentally friendly materials when decorating the space. In order to earn a LEED certificate, the applicant must satisfy an extensive list of prerequisites and earn a minimum of 40 points across the five credit categories.

These two systems give you an idea of how LEED works within the commercial industry. There are separate ratings systems for hospitals, schools, and retail spaces; each may occupy a Core & Shell-developed building, and all of them must meet the requirements in the same five basic categories. The differences will come in the necessary equipment, occupancy, and intended use of the space. Next week we’ll look at what it takes to retro-fit an existing building to meet LEED standards, and why some older structures are causing the construction industry to look at green building in a whole new way.