Volume 11, Issue 8 - October 2010

Eye On Energy

Taking a Full-Circle Approach
by Ric Jackson

Today, the majority of in our industry is centered on thermal performance. However, over the next few years, we may begin to see a shift in performance criteria to balance any trade-offs against long-term durability and compromises in the composition of products. This shift will likely come in the form of life cycle assessment (LCA) evaluations.

What is LCA?
LCA is an analytical method used to quantify a product’s environmental impact over its entire life—usually defined from “cradle-to-grave.”

Because of its holistic approach, LCA can play an important role in assessing the true environmental footprint of windows, which are commonly viewed in light of their conservation potential. As an industry, we often communicate how well our windows save energy and, as a result, help to protect the environment. However, if a window is truly going to be touted as sustainable, we need to consider more tfocushan its energy-saving potential. We also need to consider the amount of energy consumed to create the window; the efficiency of manufacturing, installation and distribution processes; product packaging; and its service life.

Wondering where to start? “Life Cycle Assessment of North American Residential and Commercial Windows: Life Cycle Goal and Scope Specification,” a report recently released by the Center for Sustainable Building Research (CSBR) at the University of Minnesota and the Athena Sustainable Materials Institute, can serve as a starting point for defining processes involved in completing an LCA. The report is a precursor to a full cradle-to-grave LCA of residential and commercial window systems. It serves as a road map for collecting, compiling and interpreting that data. This project is being funded partially by the Department of Energy.

"We also need to consider the amount of energy consumed to create the window;
the efficiency of manufacturing, installation and distribution processes; product packaging; and its service life—or, how long it will perform to its full potential in service."

Inside the Study
The CSBR and Athena Institute study will examine more than 150 window variations. Ultimately, the LCA results of these windows may be incorporated into programs like Energy Star® and included in LCA software and calculation tools available to the industry. The primary goal of the study is to provide a standardized, accurate and representative LCA of residential and commercial windows. It also aims to develop a database that would enable the modeling of a specific window type for inclusion in other LCA studies and the development of calculation tools.

Historically, LCA research for windows has primarily focused on two different aspects:
1. Window frame materials with the lowest impacts; or
2. Incremental environmental payback associated with additional window manufacturing inputs (e.g. triple glazing, low-E coatings and gas filling) relative to their long-term performance and energy savings.

However, these studies provide limited cases and don’t lend themselves well to expansive analysis due to disparate data and limited scopes.

Because windows vary greatly from one to the next in their materials, construction methods and other factors, the CSBR and Athena Institute study is necessarily limited to a few representative cases. The range of residential units to be studied includes double-hung and fixed windows, varied by double and triple glazing, low-E coatings, spacer types, gas filling and framing. The units will be modeled in six different climates, including: Miami, Phoenix, Memphis, Seattle, Denver and Minneapolis.

The CSBR and Athena Institute study will model various window types over their entire life cycle, including the window’s manufacture, maintenance, expected service life and disposal for recycling or in a landfill. It will also include an analysis of thermal performance.

Ric Jackson is the director of marketing and business development for Truseal Technologies Inc. He can be reached at rjackson@truseal.com. Mr. Jackson’s opinions are solely his own and not necessarily those of this magazine.


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