3 Rules for Choosing Windows

Windows play a critical role in the three most important aspects of home design. The first is appearance. Next to the shape of a house (Colonial, ranch, Cape Cod), windows are the most significant factor influencing how the place looks to the outside world. The second element is site embrace. Windows capture views and make the connection between the indoors and the natural world beyond. Last, windows are about comfort. They let in light and air and protect against extremes of weather. 
The power of windows is often most evident when the size, type, or location is miscalculated. Then rooms are either glaringly bright, depressingly dim, or stultifyingly stale. But if planned right, windows can be the key to enjoying your home's ambience, inside and out. Here's how to think about them.

Don't Be Bound by Tradition

Most people think of their houses — and the windows that go in them — as representative of an iconic "type," like wooden arch . But it's important to remember that virtually all traditional house styles have window designs that originated at a time when walls were not insulated, there was no central heat, and glass didn't come in pieces bigger than a dinner plate. Early builders didn't forgo picture windows by choice; the technology simply wasn't available. Does that mean that only modern houses can feature large expanses of glass? No. It's not wrong to think about big windows facing wonderful views in even the most historically "correct" houses — you just have to pick your spots wisely. In most traditional homes, that means away from the street-facing facade. (Fortunately, many street-scapes aren't worth bringing inside.) 

The Front Doesn't Have to Determine All the Other Sides

The front of a house should be friendly to visitors and convey a sense of the home's inhabitants. For many people that means a traditional, symmetrical approach, especially in a neighborhood where existing homes set a style you would like to respect (or is mandated by code). But the pattern of windows on the front of your house doesn't have to be repeated on all the other sides. If your windows are consistent in the way they are treated — basic type, grille patterns, and trim — they can handle great variations in quantity and style. 

The big mistake is to treat windows so differently that something is clearly "wrong" — say, a plate-glass window set directly adjacent to a double-hung eight-over-eight Colonial window. If you give that outsized window its own wall, and keep the trim and muntins simpatico with those in the rest of the house, you can enjoy your big view without compromising the integrity of your home's design. 

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.