DOE aims to make 'low E' windows a must-have for home construction

Ten years ago, few people knew what a compact fluorescent light bulb looked like, but today, the curly bulb is the symbol of a "green" home.

Could high-performance, insulating windows be the next CFL, the next big thing in home energy efficiency?

Energy Department officials are trying to propel so-called low-E -- for low-emissivity -- windows to popularity by bringing down prices.

Windows, and the heating and cooling energy lost through them, account for a whopping 4 percent of all U.S. energy consumption -- about 4 quads (quadrillion British thermal units) of energy, DOE says. That makes them an attractive target for efficiency improvements, especially since existing technology, in the form of better windows, is readily available to reduce that energy loss.

DOE's new tool to do so is a pedestrian-sounding volume purchase program that certifies suppliers whose products meet certain thermal, structural and cost targets and lists them on a single Web page. That page acts as a gateway for buyers, hopefully making the best products easier to find and driving up demand.


But the model is the same used in the 1990s to launch CFL bulbs from the margin to mainstream by prodding manufacturers to make the bulbs meet certain performance targets and then helping them to sell enough to bring down costs.

"We stimulate the market, and then we get out of the market, so it's self-sustaining," said Marc LaFrance, technology development manager for windows with DOE's Building Technologies Program and an architect of the effort.

LaFrance said that in the late 1990s, when the volume purchase program for CFL bulbs started, the technology goals were to make the products smaller and bring the cost below $5 per unit.

"The program started with small, proactive suppliers for CFLs, and a few years after that, major suppliers entered the market," he said. DOE ran the program for about two years, then handed it off to a private group, the Northwest Energy Efficiency Alliance, to manage.

Not long after, CFL bulbs started showing up at home supply and hardware stores, utility rebates cropped up, and the efficient-lighting market was off and running.

LaFrance warns that low-E windows are a different animal than CFL bulbs. CFLs are much easier, he explained, because the product is simpler and distribution channels are less complex.

The new DOE program covers high-performance windows for new homes, retrofits, patio doors and storm windows, and the cost analysis for each product varies by climate. It mainly targets institutional buyers like builders and government agencies with large retrofit portfolios, though individuals are welcome to buy through the program if they can meet individual suppliers' quantity requirements.

By the numbers

The volume purchase program covers windows with an "R-value" of 5, signifying a high resistance to heat passing through. (In the industry, this is more commonly referred to by a "U-factor" rating of 0.2.) That makes the standard more aggressive than the R-3 rating required for a window to be certified under the familiar Energy Star labeling program run by DOE and U.S. EPA.

Officials said the R-5 standard, together with a price target of less than $4 per square foot above the equivalent conventional window price, will make highly insulating windows cost-competitive for many consumers in cold climates in both new construction and retrofits.

DOE's analysis of the data looks promising. A small study in Chicago weatherized six older homes with highly insulating storm windows and found they reduced heating load by 20 percent, for a five-year payback.

Another review, using a sophisticated economic model with an 8 percent discount rate on the value of capital and a 25-year time horizon, found that the use of R-5 windows made sense in Boston, Minneapolis or Spokane, Wash., at DOE's target cost. In Portland, Ore., the analysis found, the windows would have to be priced more competitively with conventional ones at a premium of about $2.50 per square foot for them to make sense.

More simply, DOE's LaFrance said, those figures for cold-climate use correspond to a simple payback time in the range of five to 10 years -- a range in which some, though certainly not all, homeowners would see value in the advanced windows. In hot climates, they are not generally a good investment, he added, noting that a slightly different technology is available to help reflect heat away.

Officials involved with the program are optimistic that it will deliver the jolt needed to bring prices even below these initial target figures. Organizers were expecting five to 10 participants to start out, they said, but got 62 respondents to a solicitation issued in December 2009 and so far have certified 33 suppliers of qualified products.

LaFrance attributes the strong interest to the confluence of increased environmental awareness, and an economic downturn that has put suppliers on the offensive for new business opportunities.

The current program will run for a year, with a decision expected in the coming months about whether to re-up it for another year. LaFrance said the best opportunity in sight at the moment for it to take off would be if the R-5 standard were adopted by Energy Star when its windows program is next updated, expected in 2013. That could carry an initial wave of interest from the volume purchase program into the mass market.

'It's very controversial'

Doug Anderson, EPA's project manager for Energy Star windows, said high-performance windows were included in an early draft of the next phase specification and "really shocked people," spurring program officials to look again at the feasibility. He said the standard will continue to evolve, with research on the implications of such a standard this spring and communication with window manufacturers.

"It's very controversial, and we're going to make our decision based on where the market is [and] where the technology is," in addition to expert analysis and other factors, Anderson said.

One supporter of tough standards that can drive the technology forward is Pella Corp., a manufacturer of premium windows and a heavyweight in the industry.

Martin Wesemann, Pella's director for advanced technology, said the company has been a major partner in the Energy Star program for several years, and has been making high-performance windows for even longer.

Drawing a comparison with the way interest in hybrid-technology vehicles rose when gas prices spiked over the past few years, Wesemann predicted that the biggest push for low-E windows would come if electricity costs rose significantly.

"I think codes would have to change, also," he added, pointing to an updated set of model construction codes, widely used by states and local jurisdictions, that are due out in draft form later this year. This draft will not include R-5 windows, he said; the next revision will be about three years later.

In the meantime, suppliers will have a chance to hone their marketing messages as well as their product offerings and pricing. At the DOE launch event, just a few speakers mentioned a consumer benefit not captured in the R-factor-to-price analyses: The low-E windows also offer more indoor comfort, as residents escape drafts and the sun-baked effect felt in direct sunlight through conventional windows, as well as a quieter environment.

"We produced very highly efficient windows decades ago, but there wasn't demand," Wesemann said. "The customer has to want it."

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