Volume 34, Number 3, March 1999


re•de•fin•ing High Performance Glass

Innovative Technologies Enable a New Level of Customization

by Rick Bodette

Twenty-five years ago, the glass industry was revolutionized by the global energy crisis with architects, builders, and consumers demanding new high-performance glass systems. Today, our industry is again seeing a dramatic shift in the way we develop new products and meet our customers’ changing needs. This time, it is glassmakers who are leading this revolution, armed with innovative technologies and new insights about the effect of different climatic conditions on year-round energy consumption.

The Goal: Minimizing Year-Round Energy Consumption

The glass industry, along with our customers, has traditionally focused on narrow performance criteria in developing energy-efficient, high-performance glass systems. For homes or commercial buildings in warm climates, the goal has been to decrease the use of air conditioning by minimizing solar energy transmittance. Similarly, for buildings in colder climates, we have focused our attention on maximizing radiant heat reflection. These strategies have proven successful and have allowed architects and builders to use high-performance windows instead of traditional clear insulating units to increase both the number and size of windows without increasing energy costs.

However, the limitation of our traditional approach is that it overlooks overall energy consumption during the year, and considers only one aspect of energy efficiency. Too often, our perceptions have not been correct. For instance, while Los Angeles would seem to be a city where air conditioning usage is the primary concern, in actuality, more BTUs year-round are dedicated to generating furnace heat, even in this Sun Belt location. Given this fact, in Los Angeles and in many other warm-climate areas it would be a mistake to recommend or install a glass system that fails to take advantage of passive solar heat gain to reduce annual furnace usage.

The Solution: Custom-Tailored Glass Systems

As glass manufacturers have studied energy efficiency and seasonal BTU requirements in different areas of North America, we have responded with a new, wider range of glass systems that offer custom-tailored energy-efficient solutions for both commercial buildings and homes. For example, our company has just introduced a new residential glass system that is the first to incorporate ultrahard titanium as a coating material. To help residential builders and homeowners choose the right product for their specific climate and BTU requirements, we are offering them three distinct product options: Comfort Ti-AC is a solar heat blocker for regions where air conditioning is used most of the year, Comfort Ti-PS provides high levels of passive solar transmission in colder regions, and Comfort Ti-R provides balanced year-round energy efficiency throughout North America.

For commercial builders and architects, we offer a similar range of custom-tailored product options Comfort-ES, Sunbelt Comfort-ES, Comfort-ES52, and Comfort-ES40.

We believe this kind of product customization is the wave of the future. Not only is it the only way to achieve true energy efficiency, it is the only way we can communicate complex energy efficiency issues effectively to those who purchase and install glass products. As glass manufacturers, we naturally have a good understanding of the ways in which different coating systems can add value and increase efficiency and we owe it to our customers to share this insight with them.

In 1998, the Department of Energy and the Environmental Protection Agency began to include windows in its Energy Star® program of residential energy consumption, which approves products that are determined to be energy efficient. Recognizing that different products are needed in different geographic areas, the Energy Star program has approved a diverse array of glass products by dividing the United States into three regions: North, Central, and South. While glass manufacturers may be supplier partners of Energy Star, only the actual window can be certified for use within a specific region. This matches the customized product approach adopted by AFG and many companies in our industry and recognizes the new direction in which our industry is heading.

Improving Other Aspects of Performance

But it is important to recognize that the high-performance revolution in the glass industry doesn’t end with energy- efficient improvements. Other technological innovations are also making glass products easier to temper, handle, cut and wash, reducing fabrication costs and helping manufacturers to increase their yields. The use of titanium in our products, for example, has helped us address the traditional difficulties involved in tempering sputter-coated glass products, as well as improving durability throughout the fabrication process. Despite the hardness of the coating, however, the use of titanium ensures that the glass color remains neutral in both transmission and reflection. This is just one example of the technological improvements that are occurring throughout the industry, as we explore new materials and new manufacturing processes that enhance overall performance.

For commercial applications many manufacturers have created coatings and product innovations that allow architects and builders to meet the highest energy efficiency standards.

Rick Bodette is vice president of technical development for AFG Industries Inc., headquartered in Kingsport, TN.

 A Vi•sion of the Future

While the last revolution in the glass industry may have been driven by a worldwide energy crisis, today’s dramatic changes are being created by forward-looking glass manufacturers whose goal is to create value for those who use our products from window fabricators to commercial architects and homeowners. Armed with an array of new technologies and product innovations, we must help our customers understand what these improvements mean for them as well as help them take advantage of the best solutions we have available.

There is much talk in our industry about the "smart windows" we will see in the next century featuring state-of-the-art glass products that sense and respond to daily changes in solar radiation, HVAC system requirements, and interior comfort preferences. I believe the recent changes we’ve made in the way we view energy efficiency and the product innovations we’ve developed as a result are an enormous step toward smarter windows, as well as a new, more realistic way of defining high-performance glass products. —RB


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