Latest trend for LEED Exams

 Recently, there are quite a few readers run into the versions of the LEED exams that have many questions on refrigerants (CFC, HCFC, and HFC), the following advice will help you answer these questions correctly:

For more information, see free pdf file of “The Treatment by LEED of the Environmental Impact of HVAC Refrigerants” that you can download at link below:

This is a VERY important document that you need to become familiar with. Many real LEED exam questions (CFC, HCFC, and HFC, etc.) come from this document. You need to download it for free and read it at least 3 times.

Pay special attention to the Table on ODP and GWP on page 3. You do not have to remember the exact value of all ODPs and GWPs, but you do need to know the rough number for various groups of refrigerants.”

This latest trend regarding refrigerants (CFC, HCFC, and HFC) for LEED Exams has a lot to do with LEED v3.0 Credit Weighting. EA (including refrigerants) is the biggest winner in LEED v3.0, meaning the category  has MORE questions than any other areas for ALL the LEED exams. See pages 16 to 17 of my book, LEED BD&C Exam Guide quoted below:

How are LEED credits allocated and weighted?

Answer: They are allocated and weighted per strategies that will have greater positive impacts on the most important environmental factors:  CO2 reductions and energy efficiency.

They are weighted against 13 aftereffects of human activities, including carbon footprint / climate change (25%), indoor-air quality (15%), resource/fossil-fuel depletion (9%), particulates (8%), water use/water intake (7%), human health: cancer (7%), ecotoxity (6%), eutrophication (5%), land use/habitat alteration (5%), human health: non cancer (4%), smog formation (4%), acidification (3%), and ozone depletion (2%).“, a mnemonic for “Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts.”

2) The USGBC also used a tool developed by the National Institute of Standard and Technology (NIST) to prioritize the TRACI

3) The USGBC also created a matrix to show the existing LEED credits and the TRACI
 categories, and used data that quantify building impacts on human health and environment to allocate points for each credit.  

These 13 aftereffects were created by the U.S. Environmental Protection Agency (EPA), and are also known as “TRACI

1) The USGBC used a reference building to estimate environmental impact in the 13 categories above.

The points for Energy and Transportation credits have been greatly increased in LEED 2009, primarily because of the importance to reduce carbon or greenhouse gas emissions. Water Efficiency is also a big winner in the credits, doubling from 5 to 10 points for some LEED rating systems.

In addition to the weighting exercise, the USGBC also used value judgments, because if they only used the TRACI-NIST tool, some existing credits would be worth almost nothing, like the categories for human health and indoor air quality. The USGBC wanted to keep the LEED system somewhat consistent and retained the existing credits including those with few environmental benefits. So each credit was assigned at least one point in the new system.

There are NO negative values or fractions for LEED points.

20% reduction of indoor water-use used to be able to gain points, now this is a prerequisite in LEED 2009.


Gang Chen, AIA, LEED AP BD+C, Author of “LEED GA Exam Guide,” “LEED GA Mock Exams,” “Architectural Practice Simplified,”  and other books on various LEED exams, architecture, and landscape architecture

See all my published books at:

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