WINDOW ENERGY RATING AND LABELING

Many windows, skylights, and glazed doors now bear energy ratings or labels, similar to those being placed on household appliances, to assist consumers in selecting energy-efficient products. The labels have been developed by a non-profit group, the National Fenestration Rating Council (NFRC). The following interview with NFRC staff, provides homeowners, architects, and builders with some important information on these new window energy ratings.
 

• Question: Why are energy ratings or labels important for windows and skylights?
   
  Answer: Fenestration-windows, skylights, glazed doors, etc., can account for over 25% of the heating and cooling energy bills in a typical home. Designers, builders, and homeowners have never had a tool for determining or comparing the energy performances of fenestration products to assist them in their purchase decisions. Many manufacturers offer a variety of energy-efficient products but have not been able to demonstrate their superiority through comparable performance ratings.
  
   

• Question: How will designers and homeowners use these energy labels?
   
  Answer: Energy labels will show a variety of product performance attributes, enabling designers to compare and select products directly, based on each project's specific energy performance needs. Until now, designers have had to spend too much time trying to understand a mixed bag of rating techniques, test methods, and performance claims. A nationwide system for rating whole-product energy performance will not only give designers the energy information they seek, but will also permit direct product comparisons.
  
  Homeowners have faced a similar dilemma. When selecting fenestration products for a remodeling project or new construction, homeowners have had no way to compare the energy performances of two products directly. This difficulty has been compounded by the different energy rating techniques employed by the various industry segments. Window energy labels will enable consumers to compare products directly, regardless of glazing and frame type.
  
   

• Question: How will the energy ratings be determined?
   
  Answer: The energy ratings are determined using advanced computer tools developed in the United States and Canada, combined with standardized product performance testing. The WINDOW 4.1 program, developed at Lawrence Berkeley National Laboratory, is one of the fundamental building blocks of the rating system. This program is used to calculate the U-factors and solar heat gain coefficients of windows. Air leakage and other energy performance attributes are also being rated. Soon, homeowners will see two new ratings, Fenestration Heating Rating (FHR) and Fenestration Cooling Rating (FCR), which provide a comparative index of heating and cooling season energy use. The RESFEN program, also developed at Berkeley Lab can also be used to estimate the annual energy consumption and utility costs associated with a particular window type and orientation in a specific geographic location based on local utility costs.
  
   

• Question: Who is responsible for implementing the window energy performance rating and labeling program?
   
  Answer: The National Fenestration Rating Council has developed and is implementing this rating and labeling system. NFRC is a non-profit coalition of manufacturers, builders, state and federal energy officials, private and government laboratories, utilities, consumers, and others working together to develop a nationwide energy performance rating system that is fair, accurate, and credible. As a result of this effort, consumers across the country now have energy rating labels on windows, skylights, and glazed doors analogous to those on automobiles, appliances, and insulation.
  
   

• Question: Where might I see NFRC labels referenced or used?
   
  Answer: Several state building codes and other organizations with an interest in promoting energy efficiency, such as utilities, are already referencing NFRC ratings. NFRC ratings are a prerequisite for some special programs, such as low interest financing to purchase energy efficient windows. Look for labels on products displayed in your local building materials supply store or window store. NFRC ratings are listed in the product literature you can request from many window manufacturers, or from your architect or builder.

Note: This section is information published by The Department of Energy - it does not imply an endorsement to The Window Place.

Author: DOE Windows and Glazings Research Program Program contact: webster-btp@lbl.gov Last Update: Jan. 29, 1996