Additional Information

A window is glass held in a sash that fits into a frame.

Buying windows is not simple. Whether it's for a new home or an addition, the range of options can be confusing.

The good news is that windows are better than ever. There a wide variety of styles, frames that hardly ever need maintenance, and glazing systems that can slash energy costs. Double-pane insulated glass, heat-resistant coatings, and airtight frames can cut household energy expenditures by as much as 15 percent compared with the leaky single-pane models used in the past.

That improved technology comes at a price. While windows once accounted for 3 to 5 percent of a new home's cost, today 8 to 10 percent is more common. 

Here are some pointers to help you cut through the confusion and spend your money wisely.

The style of its windows sets the tone for a house. Punctuate a wall with two symmetrical rows of small, double-hung windows, and it looks Colonial. Fill the same wall with casements, and it is Arts and Crafts. An all-glass wall says contemporary. When choosing a style, it's important to consider the house's architecture, and also the window's locations — certain types work better in some settings than in others. 

Double-hung windows are the most popular. Modern versions have a tilt-in sash for easy cleaning of the outside panes. These all-around favorites have some limitations; for example, they're not the best choice in locations where you have to stretch to open them, such as over a kitchen sink.

Casement windows are hinged at the side and typically swing out. The full-height opening provides excellent ventilation. But casements, especially those made of wood, can suffer damage if left open in the rain. They're a poor choice where they would open onto patios or other traffic areas. 

Sliding windows function like double-hungs turned sideways. They look best in contemporary homes, and work well opening onto a deck or exterior stairway, where a casement's swing would cause trouble.

Awning windows are hinged on the top and open out from the bottom. They're often used for ventilation under large, fixed-pane picture windows in contemporary-style homes. They keep out rain even when open, as long as the wind isn't blowing too hard.

Keep Comfort in Mind

What works best on the outside to give your house a sense of scale and visual identity isn't always ideal on the inside, where windows should respond to how rooms are used and the orientation of the house to the sun and wind. 

For instance, windows facing east and west accept the very low angle of spring and fall sunlight, which can often be blinding — especially troublesome in a room used for watching television or working on a computer. 

For windows on those walls, you will need shades or curtains, or to set the sill more than 4 feet off the floor to reduce glare. Similarly, if you know in which direction the prevailing wind blows, you can increase the amount of operable glass in that area, allowing for more passive ventilation and cutting down on air-conditioning bills.

Today's windows are far superior to their older counterparts in terms of blocking unwanted drafts, but you still need to take into account radiant heating and cooling. No matter how well insulated, large panes of glass will suck heat in winter and invite it in during summer. 

For maximum comfort in cold climates, it may be necessary to have large areas of glass directly washed by a heat source, such as convective heat from a radiator or blown heat from a forced-air system (just know that this will raise your heating bill). 

On the flip side, the best way to guard against heat gain in warm weather, especially with south-facing windows, is to shade the glass with long overhangs so that the high angle of the sun during summer cannot penetrate deeply into your room. Curtains and shades are another defense.