Understanding the 40/60 rule when choosing between LEED rating systems
Wondering what to do when choosing a rating system isn't as simple as black and white?
LEED v4 addresses 21 different types of buildings and spaces, but how do you know which one to choose when you've got a mixed use space?
Enter the 40/60 rule. This model provides guidance for making a decision when several rating systems appear to be appropriate for a project.
- Step 1: Assign a rating system to each square foot or square meter of the building
- Step 2: Choose the most appropriate rating system based on the resulting percentages
- If a rating system is appropriate for less than 40% of the gross floor area of a LEED project building or space, then that rating system should not be used.
- If a rating system is appropriate for more than 60% of the gross floor area of a LEED project building or space, then that rating system should be used.
- If an appropriate rating system falls between 40% and 60% of the gross floor area, project teams must independently assess their situation and decide which rating system to use.
Don't forget, the entire gross floor area of a LEED project must be certified under a single rating system, and it is subject to all prerequisites and attempted credits in that rating system, regardless of mixed construction or space usage type.
Need more information about the LEED rating systems? Read the LEED v4 Rating System Selection Guidance.