Monday, July 7, 2008

Windows & Window Design in Your Energy Efficient Green Home (Part 1)

Windows are an important design, energy, and cost consid-
eration for a green home – whether you’re building a timber frame home, post and beam, or sustainable home using recycled and/or energy efficient material. We expect windows to enhance the beauty of our home and perform many functions: admit natural light, block summer solar heat gain, resist condensation and capture solar heat in winter (and prevent its loss).

The most common kinds of windows available are wood, clad-wood, vinyl, and aluminum.

Wood windows are traditional (wood on the interior as well as the exterior), however, wood swells and shrinks, so the window must be carefully and properly constructed and installed per the manufacturer’s guidelines. Warping and rotting will occur over time unless the window is protected. You can order wood windows either finished or unfinished. Solid ‘un-clad’ wood windows are not a typical selection.

Clad-wood windows have a wooden frame typically with extruded aluminum or vinyl cladding on the outside. The cladding completely covers the frame – meaning it won’t need maintenance for years. Most claddings have 15-year warranties on the finish and some manufacturers offer as many as 50 color selections to choose from. Clad windows are one of the most common window types.

Vinyl windows, made from rigid polyvinyl chloride (PVC), have hollow spaces inside to help them resist heat loss and condensation. While they cannot be painted, the color permeates the material so scratches do not show. Some windows have a tendency to warp when exposed to extreme heat or cold, which makes them harder to operate and allows air leakage. Vinyl windows are also a common choice and tend to be less expensive than clad windows.

Aluminum windows are thinner, lighter, and easier to handle than wood. A thermal break of extruded vinyl insulates the window, and sometimes includes foam, reducing heat loss and condensation in the window. Aluminum windows are typically more common in commercial construction than residential.

In typical residential or light commercial projects, aluminum clad wood windows are the preferred choice. The wood offers good thermal performance characteristics while the aluminum cladding protects the window from the elements. The finishes on the aluminum are available in a wide choice of colors and the interior wood finish may be left natural, stained or painted. Aluminum clad windows are also available in the typical configurations of awnings, sliders, double & single hung and casements as well, and most manufacturers offer sliding and hinged doors to match and complement their window selections.

Need help designing your new energy efficient home? Check out our architectural services and fees. In our next few blogs, we’ll talk about window styles, kinds of window frames, and energy efficiency.

Jackie Lampiasi, Marketing Director
Bonin Architects & Associates, PLLC

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