Windows and Skylights

Whether you'd like to build a sunroom, add on an old-fashioned bay, or light up a dark corner, you're in luck. Manufacturers, home improvement centers, and window stores showcase literally thousands of window styles, including arched casements and fixed windows in semicircles, ovals, trapezoids, and other shapes, all with a dizzying assortment of framing and glazing options.

If the window you want isn't standard, many manufacturers will make one to your specifications.

Window options

If you're switching to a different window style or size, check local building codes before buying; codes specify ventilation requirements and often insist on enough window space for access by firefighters. Also, energy codes govern the allowable ratio of glass to floor area.

Operable windows include double-hung, casement, sliding, and awning types. Which you choose depends partly on your home's style and partly on your ventilation needs. Frames come in wood, clad wood (encased in aluminum or vinyl), aluminum, vinyl, steel, or fiberglass. Generally, aluminum windows are the least expensive, wood and clad wood the most costly. Vinyl- or aluminum-clad wood windows and all-vinyl windows require little maintenance.

Many of the greatest strides in window technology are taking place in glazing. Ordinary flat glass can be strengthened, coated, and tinted to block solar heat yet offer pleasant light inside and a clear view outside. Insulating glass is made of two or more panes of glass sealed together with space between the panes to trap air. Low-emissivity (low-e) glass adds a transparent metallic coating that deflects heat -- outward in warm weather, inward in cold weather -- and blocks the sun's ultraviolet rays. Low-e glass is nearly as clear as untreated glass. Some manufacturers use argon gas between the panes of insulating glass to increase energy efficiency even more.

If you'd like to have some ambient daylight but don't want to lose your privacy, check out another glazing option, glass block. It provides an even, filtered light that complements many room designs.

You can buy 3- or 4-inch-thick glass blocks in many sizes; rectangular and curved corner blocks are also available in a more limited selection. Textures can be smooth, wavy, rippled, bubbly, or crosshatched. Some blocks are clear, others softly translucent.

To locate glass block, look in the yellow pages under Glass -- Block Structural, Etc. You may be able to special-order blocks through a regular glass or tile dealer.

If you live in a cold climate, consider another advancement, warm-edge windows. Instead of an aluminum spacer between panes of insulating glass, these windows have a less conductive spacer that doesn't transfer heat as readily. The result is less buildup of condensation around the edge of the window.