Volume 11, Issue 6 - July/August 2010

Energy and Environmental News

DOE Officials Say They Plan to Market R5 Volume Purchase Program Aggressively
Department of Energy (DOE) officials plan to market the R5 Volume Purchase program aggressively, and offered additional details on the program during a recent webinar titled “Cost-Effective Triple Pane (R-5) and Low-e Storm Windows— Available Now.”

The speakers highlighted DOE’s effort to bring affordable triple-pane and low-E storm windows to the marketplace at a competitive price (see related story in June 2010 DWM, page 34).
Speakers included Marc LaFrance, DOE’s technology manager for Building Envelope and Windows Research and Development, who talked about the purpose of the program.

“All of these policies are so triple-pane windows become more cost-effective,” said LaFrance. “What is cost-effective? Most windows in program have a U- factor of .22 or lower (depending on whether they are fixed or operable) and the price would have to be lower than $4 per square foot.”

On the manufacturing side, LaFrance pointed out that the DOE has been working with manufacturers on production issues, “to help them develop high-volume factories.”

LaFrance also commented on the R-value versus U-value debate, which has come up again in the industry in recent weeks (see related article on opposite page).

www.windowsvolumepurchase.org offers online information on the R5 program.

“All windows have to be based on a whole window U-factor,” said LaFrance. “We use the term R5 to give people a general perspective of window performance. It also gives people perspective of how windows relate to other building components with R values.”

He also cautioned manufacturers from offering misleading information when it comes to R-values.

“We know that there are some companies [that] report center-of-glass performance, such as an R-value of 15, and this very misleading. This program requires whole window performance,” said LaFrance.

Nils Petermann, project manager, Efficient Windows Collaborative, also pointed out to attendees that R5 windows will make the biggest impact “when there is a substantial heating season.”

Graham Parker, senior staff engineer, Pacific Northwest National Laboratory, addressed webinar attendees to stress that awards were not made to manufacturers based on price.

“You could offer whatever you were comfortable with,” he said. “Prices may not be increased during the program, but, of course, then can be decreased [if a manufacturer chooses to do so].”

He also pointed out that prices are not listed by vendor. Additionally, Terry Mapes, engineer for Pacific Northwest National Laboratory, said that 95 percent of the products offered by manufacturers are vinyl-based and that the products had to be offered minimally in a white. Some manufacturers may offer additional colors and this may or may not require an extra cost, as that is up to the manufacturer. Many of the speakers stressed that buyers will have to do research.

“It’s not set up like Amazon or buy.com,” said Mapes. The site offers list prices, but does not include shipping, taxes, etc. However, the site is set up so that buyers can choose based on shipping regions to help narrow down the search.

Phase Two of the program, which will be looked at next year, may incorporate different window types, possibly including a solar heat gain coefficient requirement, and may even expand into the commercial market, said Mapes.

But for now, the DOE needs to work to get the word concerning Phase One out. Jason Bogovich, manager of DOE contractor Energetics Inc., said he welcomes input from the industry on how to do that.

He reported that stakeholders and partners will work to get the message out to possible buyers and that includes three regional workshops that are in the works, though locations have not yet been set.

“We will be very aggressive in getting out on the street and marketing the program,” Bogovich added.

Many attendees had questions about price, but Parker reiterated that the “prices are quite wide-ranging” and clarified that there are “no subsidies to vendors.”

“We know manufacturers have been working for several years on this to lower manufacturing costs,” said Parker. “We are simply using market forces to bring high-performance products to market at lower prices.”

“The whole point is to offer these at an affordable price,” added LaFrance.

“Obviously this program doesn’t address all window types. It’s to get to mainstream and to offer at an affordable price,” said LaFrance.

Industry Discusses U-Factor Versus R-Value for Window Performance
Historically, the term U-factor, the rate of heat transfer of a material, has been used to explain window performance. However, questions have arisen recently as to whether the term R-value, which measures the thermal resistance of a material, could be used as an alternative.

It is critically important that product performance is communicated
consistently to all interested parties.
–Jim Benney, NFRC

Dr. Brandon Tinianov, P.E., LEED AP, chief technology officer with Serious Windows, has written a paper titled “The Use of R-Value Versus U-Value to Describe Window Performance,” and states “if the use of U-value is established, why would one have a desire to use R-value as an equivalent alternative?”

Tinianov explains that first, “U-values [U-factor] are small, usually less than one, with diminishingly smaller values as performance improves. In contrast, R-values are presented in a number range of highest comfort for a consumer-between 1 and 10 (possibly 20) … Second, the inverse relation of U-value and performance is counter intuitive. As U-value diminishes, performance increases.”

He also states, “There is good public reason and good technical precedence for the interchangeable use of R-value and U-factor to describe windows. With only slight modification to terminology associated with R-value, the public will be empowered to make smarter, more intuitive energy efficiency decisions.”

Recently, the National Fenestration Rating Council (NFRC) sent out a bulletin explaining why it chooses to use U-factors for windows. In the bulletin, Jim Benney, NFRC chief executive officer, says “From a technical perspective, there are numerous philosophies about whether R-value applies only to homogeneous materials and should be measured in terms of surface to surface heat transfer—i.e., making it the true inverse of conductance—by a guarded hot plate (ASTM C177). Or, should it be used for composite materials and measured in a calibrated hot box in accordance with ASTM C236? Or, should it be measured by means of a heat flow meter (ASTM C 518)?”

Benney continues, “U-factor is not a material property value. It is the result of a calculation that combines the conductance values of the numerous materials in a fenestration product. This includes glazing materials, gas fills, spacer materials, framing materials, weather strips, sealants, etc. In addition, it includes the convection and radiation elements that occur within and adjacent to the fenestration product surfaces that dramatically influence its energy rating.”

Benney adds, “It is critically important that product performance is communicated consistently to all interested parties. U-factor is the recognized term for relating the thermal transmittance of windows, doors, skylights, curtainwalls and fenestration attachment products. NFRC will continue to recognize U-factor-and U-factor only—for fenestration products.”

Some window and energy experts in the industry also have thoughts on the matter.

“U-factor takes into account not just conduction but also airflow, absorption and radiation (emissivity). Unlike most building materials that use an R-value rating and are made up of a single material component (such as insulation, roofing materials, etc.), windows are made up of many components that create the window assembly and the U-factor more accurately measures the heat transfer of this assembly of components,” says Kerry Haglund, a senior research fellow with the Center for Sustainable Research, University of Minnesota.

Tom Culp of Birch Point Consulting LLC adds, “While R-value does have greater meaning to consumers, there are also technical issues when applied to windows which have the potential to also mislead consumers if oversimplified information is given.”


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