Breaking Down Window Terminology

From on May 02, 2007 in Window Replacement

When You’re Window Shopping, Know These Terms

When you’re choosing windows for your new home, you’re likely to feel a bit overwhelmed with all the terminology. Here’s a short list to get you up the learning curve:

Aluminum: Very popular in mid to late 20th century construction, aluminum-framed windows are relatively economical and durable. Their main downside, aside from not looking right in many architectural styles, is that their metal frames tend to retain heat and cold more than the alternatives, and hence may not have the best insulation properties. Newer wood or composite windows sometimes incorporate aluminum’s durability by enclosing (cladding) the exterior surfaces in aluminum, which offers superior protection against the elements.

Argon (or sometimes krypton): An inert gas that’s often used to replace air between two panes to improve the window’s insulation properties. If the seals holding the panes in place fail, the argon rushes right out and is lost — hence, if you’re buying argon-filled windows, be sure to have them installed by an expert, and pay particular attention to the warranty on the seals.

Awning window: Close relative of the casement window, it’s hinged at the top and swings out from the bottom.

Bay window: A window, usually with three sides, that extends past the exterior wall of your house. It not only creates a sense of more space — and often an inviting window seat — it also allows more light into the room than a window that’s flush with the wall.

Bow window: Close relative of the bay window, usually made by joining multiple windows in a gentle curve.

Casement window: A window that’s hinged on one side and swings out (or, in some cases, in).

Clad: In an effort to improve the weather resistance of wooden windows, many manufacturers now offer them with the exterior surfaces coated in vinyl or aluminum, i.e. “clad.”

Composite: An alternative to both vinyl and wood frames and falling between their price ranges, these frames are made of wood strips or particles mixed with high-tech resins; they offer excellent insulation properties and durability. Unlike vinyl, they can also be painted.

Double-hung window: Window with top and bottom panels that slide up and down. Its relative, the single-hung window, has only one sliding panel; the other, usually the top, is fixed in place.

Fiberglass: Another option for frames; durable and comparable to vinyl in its insulation properties.

Glider/sliding windows: Similar to patio doors, these windows are placed in tracks and slide back and forth to open and close.

Light (also lite): Pane of glass in a window. True divided light windows feature individual panes of glass set in a grid and are referred to by the number of panes; e.g. a six-light window has six panes. A number of less expensive, faux divided light options give the illusion of separate panes to a single-light window — e.g. exterior grid overlays and grids sandwiched between panes.

Low E2: Glass that limits solar heat gain by blocking infrared and some ultraviolet light. It also allows more visible light to pass through the window than would be allowed by tinted window coatings.

NFRC label: The National Fenestration Ratings Council, an industry group, rates windows for various types of energy efficiency. Its distinctive rating label tells the particular window’s U-rating (heat transference — the lower the number, the better), solar heat gain coefficient (how much heat it lets in with the light — again, lower is better), visible transmittance (how much light it lets in — higher is better), and air leakage (lower is better).

Picture window (also fixed window): A window that doesn’t open. Used to add light and a view where ventilation isn’t an issue; often used in combinations with double-hung or casement windows. Custom shapes are popular.

Self-cleaning glass: Glass manufactured with a coating that causes water to sheet instead of accumulating in drops, and also prevents dirt and grime from adhering to the glass. The result: windows that stay clean with just rain or a squirt from the garden hose.

Tilt-wash: This welcome innovation eliminates most of the backbreaking work of cleaning windows by allowing them to be tilted horizontally for easy access.

Vinyl: Windows with vinyl frames are economical, energy-efficient and stand up very well to the elements. Possible downsides: while they now come in several colors, including faux woodgrain, they can’t be painted. Also, particularly for historic houses, their look may not work with your home’s style.

Wood: Especially for historic homes striving to maintain their authentic look, wood windows are often the best choice. They can be painted, stained and/or varnished to suit your interior and exterior preference, and offer excellent insulation. The downside: they’re relatively high-maintenance, as they’ll need to be repainted numerous times over their life to keep them from deteriorating.

Take this list with you when you’re shopping for windows. It’ll help you get through all the jargon, and ultimately make the best choice for your particular needs.

[tags]windows, window terminology, window glossary, types of windows[/tags]