What builders want in a window

II/HEN selecting a manufacturer Y V of windows, doors and skYlights, builders are concerned most about on-time shipment and the availability of product, according to a new survey by the National Fenestration Rating Council.

The survey sked builders to indicate the importance of each of l6 attributes in selecting a fenestration manufacturer, with "very important" assigned a score of 5 and "not important" assigned a score of l.

On-time completion and shipment and availability tied for first with an average score of 4.6. Warranty and service terms (4.5), durability of products (4.3), and manufacturer's reputation (4.1) rounded out the top five.

Most builders buy their windows from a dealer, lumberyard, home center or local distributor. A smaller percentage (187o) buys directly from the manufacturer. More than eight out of 10 said that they use the same manufacturer on a regular basis, and those who switch do so mostly because their regular manufacturer doesn't have the right product for a given job or the price is not right.

The survey was mailed to more than 4,100 members of the National Association of Home Builders in all 50 states and the District of Columbia. More than 807o indicated that they build single-family homes (437o customer and 39Vo specltract), with the remainder buildine multi- family housing.

The survey also found that when it comes to fenestration energy performance, builders care most about air leakage (4.3 on a five-point scale), comfort (4.2), and long-term energy performance (LTEP) and condensation resistance (tied at 4.1). NFRC currently offers an air leakage rating to manufacturers (NFRC 400), and its ratings for U-Factor (NFRC 100) and solar heat gain coefficient (NFRC 200) are directly related to comfort. In addition, NFRC is working on ratings for LTEP and condensation resistance.

Most home buyers have some say over the windows installed in their new homes, according to the survey. A little over 357o can choose from a set of options offered by the builder, whi\e 247o can choose any window they want. In all other cases, the windows are already installed when the buyer purchased the home.

"Ultimately," said one window firm representative, "it's the homeowner or home buyer who says, 'Hey, I want that particular window.' But a lot of the trends are driven by the architectural community."

The survey also found:

. Builders use energy performance ratings to help select fenestration products less often than architects. When asked to indicate how often they do so on a scale of I to 4, with I that detects the sun's intensitv and automatically raises and lowers the shhdes to prevent glare and heat gain. defined as "never" and 4 as "frequently," builders' average response was 3.2. while architects' was 3.4.

. Clients express interest in fenestration energy performance less often to builders than to architects. When respondents were asked how often clients ask about fenestration energy performance on a scale of I to 4, with I defined as "never" and 4 as "fre-

Low-E coatings - Develop new generation of scratch-resistant, cleanable coating materials

Modular windows - Design window systems with permanent frames and modular windows

Power supply miniaturization

- Develop miniature, self-contained power supplies for active windows

Recyclability - Improve ability to disassemble dissimilar window materials for recycling

Slope U-factor - Develop a Ufactor rating for sloped skylights

Solar heat gain - Develop a solar heat gain rating for skylights

Stronger sealant - Strengthen the bond in structural windows

Sunscreening - Develop skylight accessories to control conductive and radiant heat transmission

Vacuum glass - Develop commercially viable vacuum glass

Ventilation - Develop fenestration systems that regulate or condition outdoor air for indoor use

Window selection softwareDevelop software to select windows based on effects of building energy consumption

As a result, the agency has several joint industry/government projects underway, including:

Affordable highly insulating ssrogel windows

Aspen Systems is developing a equipment to produce continuous sheets of transparent, resilient aerogel with an R- l0/inch performance rating. The sheets will be used to produce clear glass double glazing windows with an R-6 rating at affordable prices.

Durable large-area EC glazing quently," the average response from builders was 2.6 and from architects 3.r

The biggest energy barrier preventing builders from gaining access to fenestration energy performance ratings is that they simply don't know where to find them (32Vo). Another 20%o said that the biggest barrier was the fact that energy codes where they work don't require ratings.

Builders mostly wanl to receive NFRC ratings in manufacturer marketing materials (457o) or a hard copy of the Certified Products Directory (32Vo). Electronic versions of the Directory, both online and CD-Rom, came in a close third.

Schott Donnelly is researching EC technology for energy efficient architectural glazing applications, focusing on improving EC device size, pedormance, durability, manufacturabilify, and cost. EC technology allows windows to lighten or darken in response to the amount of daylight and solar heat.

Integrated energ5r efficient building window and wall system

Aspen Research is testing a windodwall system that combines material and construction processes including wall construction, HVAC, framing, window installation, and utility coordination.