While Department of Energy (DOE) officials say they would love for all consumers to have access to more energy-efficient windows in their homes, Marc LaFrance, building envelope and windows research and development manager for the DOE, says he “knows that is unrealistic.” But that doesn’t mean there aren’t other options that can work alongside windows, such as attachments, which can help consumers reduce their energy usage.

“We are aiming to provide other options,” says LaFrance. Exploring these alternatives was the topic of the recent Technical Analysis Workshop for Window Attachments held in Washington, D.C.

LaFrance explains that the National Fenestration Rating Council (NFRC) provides ratings for window film, and that future ratings could include those for low-E storm windows, solar shades, exterior blinds, interior blinds, awnings and highly insulating cellular shades.

“The main ones we are looking at are exterior shading and that is a high priority for hot climates,” he says. “DOE’s mission is to help promote those products to consumers. We want them to have other options.”

Toward that end, LaFrance says the DOE, working with other interested parties, have been busy analyzing these products in the lab to move this along. The main purpose of the workshop was to give representatives of the national labs, consultants and contractors, an opportunity to lay out the technical game plan as far as priorities.

“This was a technical focused workshop,” says LaFrance. “The main action item down the road is that DOE wants to get ratings on these products in place, and to figure out how we do this while working with a third party.”

Those who attended the meeting that can help in these efforts represented various industries including window film, window coverings, low-E storm windows and even a “mainstream window company that was interested in attachments as well,” says LaFrance. Members of organizations such as the NFRC also were in attendance.

The ultimate goal, according to LaFrance, would be to give the consumer performance characteristics of other products that could be considered as a method of reducing energy usage. He cited window film as an option that would achieve this goal while also being cost-effective.

“Several elements are highly variable, however,” says LaFrance. “The performance of these attachment products will be different based on the type of windows a consumer has.”

How consumers use these products also plays a role.

“Once you put a window in, if the homeowner keeps the shades closed they won’t get passive heating, or in the summer if they leave a shade open they will get more solar heat gain,” he says. “The operating behavior is important. So not only do we have to look at the technical aspects we have to look at what conditions these are being installed.”

Is an Energy Star rating for some of these attachment products a possibility? LaFrance says this is what some associations are after, such as the Window Coverings Manufacturers Association.

“While we think Energy Star would be good, there are also other things like rebates, tax credits, and voluntary programs,” he says. “There are many other avenues for supporting these products in addition to Energy Star.”

To view the presentations from the workshop visit the DOE’s website.


1 Comment

  1. As far as summer time energy savings for air conditioning, DOE is on target by focusing on external attachments to reduce infrared heat loads from sunlight. Solar scrrens are already in the market and reduce IR heating by 80-90%. They mount externally and are recommended for permanent installation. They maintain a view and darken the room some. Solar grates produce similar savings but leave the room bright while maintaining a view. This is because they operate through selective reflectivity. Grates are designed for seasonal use. Thus free solar heating in winter is maintained. Maintenance is nil. Other options include awnings and functional shutters. New shutter designs leave the room bright while maintaining a view. The brightness is important for the interior and leaves open the possibility for reduced artificial lighting while the sun shines, thus creating addtional savings possibilities.

    It will be useful for DOE/LBNL to indicate where updates on their work may be found so that the public can track the progress. So far, it looks like they are offf to a good start.

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