At work I'm frequently tasked with providing empirical support for sustainable design strategies for clients who may be on the fence or don't really understand what this LEED thing is all about. Over the next few months I'm going to be providing what I've found to be some of the most convincing arguments. Today we begin with an excellent new study out of California (go figure)...
A joint CBRE and University of San Diego study examining the impact of LEED and Energy Star buildings on occupant productivity provides an excellent argument for sustainable design that a CEO could understand that isn't based on expected utility savings... a rare study indeed! Even more interesting, the study provides a strong argument for a more comprehensive concept of sustainability, one including indoor environmental quality efforts in particular, by showing how LEED projects far surpass Energy Star buildings with regard to reduced absenteeism.
Summarizing the Old
Documentation of the economic benefits of indoor environmental quality measures have been few and far between, and the best part of this study is that it does an excellent job of succinctly laying out what previous research has already determined:
- Temperature: "The highest productivity is at temperature of around 22 degrees C (71.6 degrees F)..." (page 9)
- Indoor Air Quality: "It has now been shown beyond reasonable doubt that poor indoor air quality in buildings can decrease productivity in addition to causing visitors to express dissatisfaction... The size of the effect on most aspects of office work performance appears to be as high as 6 - 9%, the higher value being obtained in field validation studies." (page 9)
Exposing the New
What CBRE and USD added to this investigation is a survey of 154 buildings holding over 2,000 tenants in office environments spread across the nation. 99.5% of respondents reported equal or increased productivity in LEED or Energy Star labeled environments, and 90% reported equal or reduced absenteeism. Here is the quote that I found most interesting:
“The 10% that reported more sick time after moving were in Energy Star-labeled buildings and not LEED certified. It appears that they suffer what often happens to new buildings when ventilation systems are not kept clean or VOCs are not eliminated from new construction materials and finishes… we should emphasize that these are not LEED buildings.”
The bottom line: if you want to harness all of the benefits of a sustainable building, you cannot focus on energy efficiency alone! So just what are those benefits from an economic standpoint?
Mo' Money, Mo' Money, Mo' Money! (see page 17)
Of those reporting increased productivity, the average productivity increase was 4.88%, resulting in an annual benefit of $5,204 per worker. When considering LEED only buildings, the average impact was 5.24% ($5,588).