NFRC Update

Manufacturers Continue to Improve Energy Performance of Fenestration Products

Energy lost through windows accounts for 15 percent of the energy consumed by the nation’s residential and commercial buildings, according to the U.S. Department of Energy’s (DOE) Building Technology Program. As a result, energy efficient fenestration products – doors, windows, skylights, and curtain walls – are a top priority for the public and private sectors.

“Using high performance fenestration in new construction or renovated buildings can help homeowners, businesses, and others save money on utility bills and reduce greenhouse gas emissions,” says NFRC Executive Director Jim Benney.

Many technologies used today have been around for years, but they are continually being refined and today’s high performance residential windows offer better energy savings than products from a decade ago. Window companies want to achieve the highest performance they can because it gives them a competitive advantage, explains Mike Mooney, director of residential glass programs for Guardian Industries Corp.

“We’ve been able to lower the solar heat gain numbers significantly and improve the U-values,” Mooney says. U-value, or U-Factor, is a measure of heat loss through a product. For colder climates, windows with low U-values minimize the heat that escapes through windows in the heating season.

Low-e Coatings
A low-emissivity (low-e) coating – an incredibly thin layer of metal applied to a pane of glass – is an important component of today’s high performance windows because it reduces the heat transfer through the glass. The percentage of low-e windows on the market is still growing, says Mooney. Consumers would be surprised at the number of different low-e windows available, he explains, and may not realize that different low-e windows can be installed on different sides of a house to maximize energy savings throughout the year.

And, those residential products for the home don’t necessary look like the tinted glass commonly found on large office buildings. Manufacturers are striving to make products as clear as possible, using spectrally selective low-e coatings.

Jim Larsen, director of technology marketing with Cardinal Glass Industries, points to the flexibility of sputtered silver coatings as an example. Larsen explains that his company offers several products using this technology, which provide the insulating value of a quad pane unit with the appearance of clear glass.

This month, Guardian Industries introduced a product with high visual transmittance optimized for homes in northern climates to take advantage of passive solar heat gain in the winter. This could help homeowners reduce their heating bills.

Efficient Technologies Spur Other Features
As low-e coating technology becomes more common, it has provided an opportunity for manufacturers to add new features to glass. For example, Cardinal Glass Industries can apply a low-e coating to one side of a pane of glass – to save energy – and a photo-catalytic coating to the other side, so that water sheets off and dries quickly without spotting. The low-e process enables the other feature to be cost-effectively added to the product thanks to production efficiency.

There are also many different types of frames on the market, offering a range of energy performance. DOE’s Office of Energy Efficiency and Renewable Energy provides consumers with information online about the benefits and disadvantages of different framing materials. Larsen observes that many manufacturers are shifting to more efficient framing materials in an effort to maximize window performance while keeping pace with the advances in glass technology.

Today’s energy efficient windows often feature two or three panes of glass to save energy as well. These products may be called insulated, double-glazed or triple-glazed windows. Sometimes inert gases are sealed in the spaces between those panes to minimize the energy transferred through the window. While these types of windows are a dramatic improvement over old, single-pane glass, there is still room for improvement.

Fenestration’s Future
Some researchers are studying windows that have had air entirely removed from the spaces between the panes of glass. The vacuum created in the space would greatly reduce the transfer of energy.

When it comes to advancing low-e coating, “we’re going to see more and more low-e designed for specific climates,” says Mooney. “As technology to lay down sputtered film has improved, you can make low-e do more.”

In the near future, the ENERGY STAR® windows program may play an important role in high performance fenestration products. Mooney thinks that proposed revisions to ENERGY STAR criteria could spur significant changes in the marketplace. On the residential side, Mooney says that the industry is “very focused on how we reach those levels of performance.” Manufacturers may need to use different low-e products for different climates, he explains.

As a share of the marketplace, “we’re continuing to see energy efficient windows grow,” says Mooney.

“Many states reference NFRC’s rating and labeling procedures in their energy codes,” says Benney. “We are proud to have programs that help consumers and builders select the right high performance products for their needs,” he adds.

Larsen thinks that improving energy efficiency codes and/or adopting them where they don’t exist would do more to increase window efficiency than ENERGY STAR. “Real world market transformation with long-term energy benefits happen when code minimums are rigorously enforced for both new construction and replacement,” he says.





		Manufacturers Continue to Improve Energy Performance of Fenestration Products Energy lost through windows accounts for 15 percent of the energy consumed by the nation’s residential and commercial buildings, according to the U.S. Department of Energy’s (DOE) Building Technology Program. As a result, energy efficient fenestration products – doors, windows, skylights, and curtain walls – are a top priority for the public and private sectors. “Using high performance fenestration in new construction or renovated buildings can help homeowners, businesses, and others save money on utility bills and reduce greenhouse gas emissions,” says NFRC Executive Director Jim Benney. Many technologies used today have been around for years, but they are continually being refined and today’s high performance residential windows offer better energy savings than products from a decade ago. Window companies want to achieve the highest performance they can because it gives them a competitive advantage, explains Mike Mooney, director of residential glass programs for Guardian Industries Corp. “We’ve been able to lower the solar heat gain numbers significantly and improve the U-values,” Mooney says. U-value, or U-Factor, is a measure of heat loss through a product. For colder climates, windows with low U-values minimize the heat that escapes through windows in the heating season. *Low-e Coatings* A low-emissivity (low-e) coating – an incredibly thin layer of metal applied to a pane of glass – is an important component of today’s high performance windows because it reduces the heat transfer through the glass. The percentage of low-e windows on the market is still growing, says Mooney. Consumers would be surprised at the number of different low-e windows available, he explains, and may not realize that different low-e windows can be installed on different sides of a house to maximize energy savings throughout the year. And, those residential products for the home don’t necessary look like the tinted glass commonly found on large office buildings. Manufacturers are striving to make products as clear as possible, using spectrally selective low-e coatings. Jim Larsen, director of technology marketing with Cardinal Glass Industries, points to the flexibility of sputtered silver coatings as an example. Larsen explains that his company offers several products using this technology, which provide the insulating value of a quad pane unit with the appearance of clear glass. This month, Guardian Industries introduced a product with high visual transmittance optimized for homes in northern climates to take advantage of passive solar heat gain in the winter. This could help homeowners reduce their heating bills. *Efficient Technologies Spur Other Features* As low-e coating technology becomes more common, it has provided an opportunity for manufacturers to add new features to glass. For example, Cardinal Glass Industries can apply a low-e coating to one side of a pane of glass – to save energy – and a photo-catalytic coating to the other side, so that water sheets off and dries quickly without spotting. The low-e process enables the other feature to be cost-effectively added to the product thanks to production efficiency. There are also many different types of frames on the market, offering a range of energy performance. DOE’s Office of Energy Efficiency and Renewable Energy provides consumers with information online about the benefits and disadvantages of different framing materials. Larsen observes that many manufacturers are shifting to more efficient framing materials in an effort to maximize window performance while keeping pace with the advances in glass technology. Today’s energy efficient windows often feature two or three panes of glass to save energy as well. These products may be called insulated, double-glazed or triple-glazed windows. Sometimes inert gases are sealed in the spaces between those panes to minimize the energy transferred through the window. While these types of windows are a dramatic improvement over old, single-pane glass, there is still room for improvement. *Fenestration’s Future* Some researchers are studying windows that have had air entirely removed from the spaces between the panes of glass. The vacuum created in the space would greatly reduce the transfer of energy. When it comes to advancing low-e coating, “we’re going to see more and more low-e designed for specific climates,” says Mooney. “As technology to lay down sputtered film has improved, you can make low-e do more.” In the near future, the ENERGY STAR® windows program may play an important role in high performance fenestration products. Mooney thinks that proposed revisions to ENERGY STAR criteria could spur significant changes in the marketplace. On the residential side, Mooney says that the industry is “very focused on how we reach those levels of performance.” Manufacturers may need to use different low-e products for different climates, he explains. As a share of the marketplace, “we’re continuing to see energy efficient windows grow,” says Mooney. “Many states reference NFRC’s rating and labeling procedures in their energy codes,” says Benney. “We are proud to have programs that help consumers and builders select the right high performance products for their needs,” he adds. Larsen thinks that improving energy efficiency codes and/or adopting them where they don’t exist would do more to increase window efficiency than ENERGY STAR. “Real world market transformation with long-term energy benefits happen when code minimums are rigorously enforced for both new construction and replacement,” he says.				*ALSO IN THIS ISSUE* Back to Home Page >>> Executive Director’s Message >>> Manufacturers Continue to Improve Energy Performance of Fenestration Products >>> Utilities’ Incentive Programs Help Customers Save on Efficient Windows >>> CMA Software to be Unveiled at NFRC Summer Meeting >>> DOE Completes Initial Analysis for Proposed ENERGY STAR® Criteria Revisions >>> NFRC Discusses Energy Codes and Fenestration at AIA Show >>> Codes Update >>> Industry Trade Publication Launches Green Web Site >>> NFRC Membership Meeting Set for Chicago, Illinois >>> NFRC in the News >>>



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