Greening Your Building through Windows and Doors

New window and door technologies make it easier to control a building's energy efficiency.

Windows are often one of the larger building items considered in a retrofit because of how much energy can be lost through older windows. Conserving energy, lowering operating costs and complying with various codes has pushed the industry toward a mindset of using fewer windows.

“As the codes ratchet down and become more stringent it puts design hindrances on them in terms of how valuable their space is,” says Erich Klawuhn, vice president of business development at Soladigm. “They see smart glass and technologies as an enabler to both get what they need from a value of the building as well as getting that energy performance.”

The majority of glass that comprises windows is static, consequently compromising the performance of the glass to balance light, visible clarity and energy performance. But the advent of smart windows, which can change their performance based on certain conditions, such as a change in heat or light, is changing that.

Currently there exist three different technologies in use in smart glass products: photo-chromic technology responds to different light conditions—similar to transitional eyeglasses—thermal-chromic responds to glass temperatures and electro-chromic uses an applied electrical charge to change its properties.

“It electronically has the ability to tint, which gives you the most flexibility on how you control that glass … It can be very intelligent based on occupancy, light, temperature or HVAC loads,” explains Klawuhn. Soladigm is developing what it calls dynamic glass, which uses electro-chromic technology. The product is expected to be ready for sale in early 2012.

Rather than applying a low-emissivity coating to the glass, Soladigm applies an electro-chromic coating and forms an insulated glass unit of two panes of glass with a gas gap in between.

“If you have a variable tint glass in your window that controls both light or glare and heat load, it gives some big benefits. Today in multifamily homes you apply some sheer blind or an integrated privacy blind to control the amount of glare that comes into the space. If you think of high-rise dwellings, there’s a lot of glass used in those because you usually have a nice view from that building. With that large glass and view comes a lot of glare,” points out Klawuhn.

With smart windows, he adds, “you can completely change the way occupants feel and interact in a space because you are able to do glare control without blocking the views.” At the same time, the building’s peak load is reduced, thus allowing 30 percent less HVAC equipment to be installed.

Product picks

NanaWall Systems recently introduced NanaGlass SL25, a frameless opening glass wall system installed on the exterior of balconies and patios, and under second-story decks. With no vertical stiles, the NanaGlass system provides uninterrupted views and natural light while forming an insulating air pocket over the building facade. The NanaGlass SL25 ½-inch glass panels are engineered to withstand wind loads up to 80 stories in 90 mile-per-hour wind zones. Additional features include hundreds of finish options; SL25 version units can be supplied glazed with either 3/8” (10 mm) or 1/2” (12 mm) thick single tempered glass; all weather stripping consists of APTK and brush seals and is provided for sealing between panels and frame; top-hung sliding/turning hardware; two-point locking with concealed top and bottom latches operated by the pull of a spring tensioned cable (

Ply Gem’s energy-efficient Ply Gem Windows Premium Series 1000 vinyl new construction and replacement windows are now available in the western United States. The series includes double-hung, sliding, fixed and geometric shapes, as well as the 960 Hinged Patio Door. The series features a flush mount lock system and is available in a new, darker beige color. Offered as a standard feature is a patented R-Core insulation in the frame, and for added energy efficiency and durability, the Energy Package option upgrade includes R-Core in the sash and frame along with Interforce II fiberglass reinforcement in the meeting rails of double hung and sliding windows. The Ply Gem Windows Premium Series 1000 for the replacement and new construction windows markets meets the Energy Star standards for 2010 (

Solar Gard’s architectural solar control window films can help buildings consume up to 30 percent less energy for cooling by stabilizing interior temperatures and transforming existing standard glass into high-performance windows. Its window films are carbon-negative. Solar Gard recently made available its environmental product declaration (EPD) (

The offerings in Integrity Windows and Doors’ All-Ultrex series are made from Ultrex, a pultruded fiberglass that’s stronger, more fade-resistant and more energy-efficient than vinyl. The Sliding Patio Door (pictured) features tempered Lo-E insulated glass and is available in two- or three-panel configurations, in heights up to 8’. The finishing process yields a finish three times thicker than competitive finishes to resist scratching and marring, while five times the UV resistance protects against the fading, chalking, streaking and cracking common to vinyl windows (

JELD-WEN’s FiberLast exterior doors are Scientific Certification Systems (SCS)‐certified to contain at least 35 percent pre‐consumer recycled wood for the door slabs. FiberLast is engineered to save energy and meets 2010 Energy Star requirements for a tax credit of up to $1,500. Its solid wood stiles are made with JELD‐WEN’s AuraLast process that reportedly releases 96 percent fewer volatile organic compounds (VOCs) than traditional dip treatment processes. The line offers dozens of glass types, sidelights and doors styles, including seven‐ and eight‐foot doors and stainable options (