Ludwig Mies van der Rohe's Farnsworth House and Philip Johnson's Glass House stand as seminal works of minimalist architecture. Few who laud the uninterrupted roofs and floor planes, however, would want either house as their home: The large expanses of glass make both houses demanding and expensive places to live.

But that was glass technology as we knew it in the 1940s. Today, glass is no longer the energy-hogging product it once was. Advances in manufacturing techniques have led to a new generation of products that conserve energy, block UV rays, minimize heat gain or radiate heat, and offer privacy with the flick of a switch.

Thanks to its transparent quality, glass has and always will play a vital role in architecture. “It's a natural human desire to be connected to the outside world,” says Chip Fogg, brand communications manager for laminating solutions at Wilmington, Del.–based DuPont, a maker of the interlayer used in laminated glass. “More natural light means less energy used for artificial lighting. People prefer bright spaces, and glass makes that possible.”

But as glazing has evolved, so its usage has increased, says architect Bruce Norelius. “As an architectural element it's everywhere,” the principal of Elliott Elliott Norelius Architecture in Blue Hill, Maine, says. Norelius' firm has started shifting toward more architectural glazing systems as it takes on more commissions for Modern projects. “We still use our share of Marvin, but we do a lot more with [other types of glass],” he says.

New York City architect Louise Braverman is a longtime fan of the architectural possibilities of glass and specs it in her work whenever she can. “It works in a Modernist way that allows you to do a layering of space,” she says. “It can be used anywhere because it's universal.”

Twelve years ago, DuPont launched the DuPont Benedictus Awards to recognize innovative architectural projects that use laminated glass. A prominent member of the glazing family, laminated glass provides impact resistance and UV- and sound-reducing benefits. That's why New York City–based James Carpenter Design used it in its Dayton House project—a DuPont Benedictus Awards honorable mention in 2001. The firm sought security, a connection between indoors and out, and something environmentally efficient. The solution: Four extra-clear ¼-inch sheets of glass were laminated to form one doubled-layered insulating unit.

Lorcan O'Herlihy's interest in glass began while working at Steven Holl's New York City office in the 1980s, but moving out to the sunny climes of California allowed him to do more experimentation with glazing. “The nature of the place allows you more opportunity to do a transparent house,” says the principal of Lorcan O'Herlihy Architects in Culver City, Calif. Today, O'Herlihy is known for homes in which the interplay of transparency and opacity is a prominent characteristic. Although he prefers regular glass used in interesting ways, one of O'Herlihy's favorite products is Profilit, a translucent linear structural glazing system made from self-supporting glass channels. Manufactured by Toledo, Ohio–based Pilkington but marketed by West-crowns in Sunset Beach, N.C., the product lets in light but preserves privacy.

glazing inferno Profilit is just one of the interesting new specs on the scene. German glass manufacturer Schott North America, which has an Elmsford, N.Y., office, boasts a variety of revolutionary products, including semitransparent photovoltaic glass panels that lower energy costs, provide glare protection, and supply heat insulation. The company also offers LightPoints, which incorporates light-emitting diodes into transparent glass.

Pilkington's Activ self-cleaning glass has a coating that helps the surface stay clean for longer, while its latest iteration, Pyrodur 20-200, blocks 90 percent of radiant heat during a fire. If solar control is your need, Pittsburgh-based PPG Industries' Solarban line of solar control low-E glass reduces heating and cooling costs but still maintains transparency. PPG also offers a self-cleaning glass. IQ Glass, a Belgian company with U.S. headquarters in Arlington, Va., manufactures a glass that is hardwired to produce radiant energy for warming a room. The manufacturer says the product can be a room's primary source of heat.

Most architects think of using laminated glass when they need an impact resistant product, but it also has architectural possibilities, Fogg says. “An architect could order laminated glass that is etched or frosted for decorative effects,” he says. But pros may also spec laminated glass with decorative film. Paragon Glass Industries, for example, makes Naturalam decorative laminated safety glass using natural wood interlayers.

Frosted or etched glass is good for privacy, but also available is glazing with suspended particle device (SPD) light-control technology by Research Frontiers in Woodbury, N.Y. A thin SPD film containing microscopic particles is laminated between standard panes of glass so that when a small voltage is applied to the film, the particles “line up” and allow light to pass through. Adjusting the voltage controls the amount of light passing through the window.

Architects also are fans of textured and corrugated products from such outfits as Bendheim in Passaic, N.J., Richmond, British Columbia–based Nathan Allan Glass Studios, and Joel Berman Glass Studio in nearby Vancouver.

taking panes This just etches the surface of new products available, but it's enough to generate excitement. However, you'll have to dig deep into your budget to spec them; many of these products cost up to five times more than regular glass. Economics often relegates them to the upper end of custom work.

Architect Dan Rockhill knows this all too well. The principal of Rockhill and Associates in Lecompton, Kan., loves glass, but often cannot use the fancy stuff because of cost. “For our modest projects, we cannot find a way to make it inexpensive,” he says. Rockhill, however, has found a way to create the look without the loot. Ordering regular glass from his supplier, he uses a machine to sandblast the glass on site for a fraction of the cost of frosted or etched glass.

Bendheim is one of Braverman's favorite glass suppliers for colored satin-etched glass, but the high price means she uses it sparingly. “It's not something you put in every project,” she says. “The budget has to sustain it.” When the budget is tight, she uses a local supplier for a variation on the product.

In addition to cost, architects also must weigh when to use glass. “You just can't build a glass house anywhere and in any climate,” O'Herlihy says. “You need to look at issues of heat, you need to look at privacy, and you need to think about the position of the house on the site.” In addition, consider how the clients live in the space and what their personal thresholds are for exposure.

The good news, Bruce Norelius says, is that there are glass options to solve almost any problem. All it takes is a little planning and a lot of research. The bad news, however, is that the truly tantalizing glass products are currently restricted to the European and Asian markets. There are still great products here, he says, “but we see stuff in European magazines, and we just can't get information on how it works and how they did it.”