Beyond R-value

Energy efficiency is more than just one number
Jenni Chase
September 7, 2010

Growing up amidst her father's metal cutting business, Charlotte Broussard developed a love of manufacturing at an early age. For the last 11 years, she's applied that love to the commercial window business as owner and CEO of Universal Window and Door, Marlborough, Mass. In the following interview, she discusses the need for a comprehensive thermal efficiency rating system, as well as the growing commercial retrofit market, with Glass Magazine Editor Jenni Chase.

JC: The Department of Energy is promoting R-5 and looking to have such products specified, particularly in multifamily projects. That's a tough number for an aluminum window manufacturer. What's Universal's perspective on this initiative?

CB: First of all, it's not just difficult for the manufacturers. It is also difficult for the builders, developers and homeowners, who are concerned with durability, life cycle assessment and sustained operability, in addition to thermal efficiency.

The assignment of an R-5 by itself defeats the spirit for which the code is written, which is to save energy.

Expansion and contraction rates, durability, wind-load and window performance in extreme temperature conditions all need to be considered along with the R-value. The durability of a product, for example, can drastically affect the rate of air leakage, which can negate the benefits of an R-5 rating. Using an R-5 as the sole attribute of a product's energy efficiency limits fenestration options, thereby ignoring the overall building envelope's performance.

The AAMA [American Architectural Manufacturers Association, Schaumburg, Ill.] standards that the aluminum industry has been [subject to], test energy efficiency by measuring both conduction and air infiltration at various wind speeds. There is also an AW standard that measures the energy performance of a product after years of use. We believe that this provides a more real-world standard. There is no such accountability with an R-5 rating. Indeed, many of the products that can easily achieve an R-5 rating find it impossible to meet commercial building codes for structural performance and water resistance.

JC: What is Universal's stance on the ever-tightening codes and standards? How do you anticipate the industry will respond?

CB: Tightening the codes and standards is absolutely necessary, but the standards need to be the same for all products. Mandating products' viability solely on conduction is not the answer. We believe that the industry should be able to comply with the codes without compromising safety and owner-driven requirements in regards to aesthetics, cost performance, maintenance, etc.

JC: What questions does Universal commonly field from contract glaziers?

CB: Many of the questions often involve value engineering. In these economic times, value engineering is important, but not at the expense of thermal efficiency. Therefore, we are constantly educating people about building codes and the importance of new, improved technologies.

JC: As a supplier of windows for historic applications, are you seeing demand for commercial retrofit projects increasing?

CB: Yes, we've seen an increase due to both energy savings and historic tax credits. Historic tax credits have really benefited many towns. People are taking buildings that have been abandoned and converting them into commercial and residential space. Years ago, mills, for example, had huge windows because they needed the passive light. However, over time, these historic buildings have been boarded up. Now, we are seeing a resurgence of these abandoned buildings being re-opened and given a new life. The architects' and developers' visions for these abandoned properties have achieved phenomenal results.

JC: Are there any product trends that you are particularly excited about?

CB: In addition to reducing U-factors with gases and triple glazing, we currently have achieved a .2 U-factor for a fixed aluminum window and a .32 for an operable aluminum window. But the most exciting trend is the launching of our new Universal FiberView Series Windows. Our FiberView Series made of fiberglass combines durability, sustainability and thermal efficiencies that are so necessary for our future. We are also testing an aluminum/fiberglass hybrid to enhance the assets of both materials. 

Jenni Chase is editorial director of Glass Magazine, e-glass weekly and Write her at