Design for Sustainability, Part 2

Continuing from last month’s blog focusing on workplace trends and challenges, I ask the question: What are the cost impacts and paybacks of having high-quality work environments?

A helpful tool to understand these challenges and complexities was created by the National Institute of Building Sciences (NIBS) called the Whole Building Design Guide (WBDG). Many of you have heard of it. It gets updated section by section over time. Initial building costs account for approximately 2 percent, operations and maintenance costs equal 6 percent, and personnel costs equal 92 percent (PDF download: Sustainable Building Technical Manual). It doesn’t take a math whiz to figure out that minor investments in building costs to create highly satisfying, productive and healthy work environments can have huge paybacks. It’s also worth noting that by March 2014 the WBDG had more than 625,000 users downloading approximately 7 million documents per month!

Another perspective on calculating the investment payback of high-performance buildings was provided by the New Buildings Institute (NBI) in its recently released study “Net Zero and Living Building Challenge Financial Study” (PDF download). NBI studied buildings in Washington, D.C., “to investigate costs, benefits and approaches necessary to improve building performance in the District of Columbia from LEED Platinum to zero energy, zero water and Living Building status” and “to advise District government on policy drivers related to deep green buildings…”

The NBI study concluded: “the cost premium for energy efficiency was approximately 1-12% depending on building type”… which “rose to 5-19% for net zero energy.” If an owner is willing to employ various tax and energy credits, the return on investment can be approximately 30%, “whereas the return on investments for energy efficiency alone was in the range of 5-12%.”

Regarding glazing, the study model chose to reduce window to wall ratio from 48 percent to 35 percent for new construction buildings, though this change introduces challenges regarding daylighting design. The amount of opaque spandrel area of the total curtainwall used in the study was approximately 10 percent, with improved thermal insulation of the spandrel area using rigid insulation. The whole unit U-values they used for both new construction and remodeling were 0.22 though the study acknowledged this could be improved on with the use of triple glazing.

These choices left me with two thoughts:

  1. It would be quite interesting to see the impact on this analysis of keeping the higher percentage of window to wall ratio, while using higher performing glazing. Customers of our company are achieving substantially lower unit U-values using our frame and glass insulation technologies, with many success stories of installed jobs.
  2. A higher percentage of opaque spandrel area is commonly used to improve whole building energy performance. Up to 50 percent ratio of spandrel to vision area is often used to meet or exceed codes, depending on the performance targets. Additionally, how much better of an outcome would have been attained if one the new methods of insulating spandrel area were used in addition to the rigid insulation that was added?

I have a high degree of respect for the objectives of net zero buildings and the aspirational goals of the Living Building Challenge. These efforts are raising the bar within the built environment’s understanding and measurement of holistic energy performance. It is crucial that we evolve corresponding analytical and evaluation methodologies for the human impacts of buildings on their occupants. Only then will a comprehensive, scientific understanding of the true contribution of glass and glazing evolve.

As an industry, we understand the benefits that high-performance glass and glazing systems can offer building owners in terms of energy and operational savings. Now that owners, government agencies and research organizations are amplifying our messages of the critical performance contribution of glass and glazing, we have an even greater opportunity to influence buildings’ most important and most valuable assets – the people who occupy these spaces. Let’s make a positive impact in their lives for generations to come.


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