Features
The traditional single sheet of clear glass offers little insulation against frigid winters and frying summers. With energy
conservation a major issue these days, the market
Double or triple glazing
Double-glazed windows have a sealed space between the two panes of glass, and the air in the space provides an added layer
of insulation. Compared with a single pane, double glazing can cut heat loss nearly in half. The insulating value of triple-glazed
windows is higher still, but the extra layer adds to weight and cost.
Low-E coating
heat out from your house in winter. A low-E, or low emissivity, coating is a microscopically thin metallic film that acts
something like a two-way mirror, reflecting heat back into the house in winter and blocking heat from the sun in summer. Which
it does better depends on how the coating is applied. The windows can be fine-tuned for different climates, producing Southern
or Northern windows, for example. Some coatings may darken the glass, like tinted glass in a car, an effect some people might
not like. Check a sample at the store.
Gas filled
Instead of air in the sealed space between glass panes, these windows use argon, krypton, or other inert gas. These gases
are denser than air, so they provide better insulation.
Cladding
This is the vinyl or aluminum that covers the exterior of a wood window so that it doesn't have to be painted.
Tilt-in sashes
On windows with this feature, the sash (moving part of a window) can be tilted for easy cleaning.