Energy codes mandating more efficient use of buildings—and, by extension, of building enclosures—are already being adopted by many states as a logical step in the reduction of energy consumption.
On a national scale, the impetus to improve building energy performance is manifest in the latest and most far-reaching model energy code from the International Code Council, the 2015 International Energy Conservation Code (IECC). Compared with energy standards of just a few years earlier, the 2015 IECC sets a high benchmark for energy performance.
In 2010, the required insulative value for a new roof on an existing commercial building was R-20, per the IECC. Today, it’s R-30, a 50% increase. Replacement fixed windows in 2010 needed to perform at R-1.82. Now, that number is R-2.38, 30% greater.
This trend toward increasingly stringent energy performance standards is likely to continue. Several states and municipalities, including New York, New Jersey, and Maryland, were early adopters of the 2015 IECC. Others have already passed legislation to roll out the new, more demanding energy standards over the coming months.
For design professionals, designing and detailing building enclosures to meet these strict performance benchmarks demands knowledge not only of building envelope systems, but also of the requirements and objectives of the energy code, the fundamentals of thermodynamics and energy transfer, and high-efficiency enclosure detailing.
For property owners and facility managers, understanding the code requirements for energy-efficient design, the science behind those standards, and the process involved in achieving energy performance goals is critical to an informed and judicious approach to planning construction that meets stringent energy mandates.
After reading this article, you should be able to:
+ Balance energy use goals with practical considerations, such as constructability, performance, and product availability.
+ Apply principles of thermodynamics and energy transfer to the appropriate design of energy-efficient building enclosures.
+ Determine energy code compliance by demonstrating thermal efficiency through calculations or energy modeling.
+ Account for sites of thermal bridging by incorporating high-efficiency detailing that addresses sources of energy loss and insulates against heat transfer.