What is impact glass?

Impact glass is a laminated glazing product, produced by bonding a combination of plastic vinyl layers and polyester film between two pains of glass into a single sheet. Laminated glass looks like ordinary glass, but protects like a shield against accidental impact, forced entry, sun damage and unwanted noise. Tests show that specially designed laminated glass products pass windborne debris impact tests, and when broken the glass fragments tend to remain integral, adhering to the plastic interlayer, helping to preserve the integrity of the building envelope. Impact glass is provided in a Low-E configuration, but it does not have an open space between the two glass panes.

What does Low-E stand for and how does it benefit my project?

Low-E stands for low-emissivity, which is the power of a surface to emit heat by radiation. This type of glass cuts the loss of heat during the winter and cuts the absorption of heat during the summer by reflecting the heat back to its source, thus providing year-round savings by lowering utility bills. Low-E glass also selectively filters the sun’s energy, blocking up to 84% of the sun’s ultraviolet rays in the summer, thereby reducing the degree of fading of upholstery, carpet and drapes. Low-E also reduces heating costs reflecting room side heat back into the room with a resulting in a lower winter U-value.

What is insulated glass?
Technically, there are two or more panes of glass separated by insulation at the edges and air in the center to provide greater thermal efficiency to a window.

What is a gas-filled window?
Modern window technology permits an inert gas, usually argon, to be sealed between the panes of glass in a window instead of air. The gas is a far better insulator that just air, thus further increasing the thermal value of a window.

What are some common styles of windows on the market today?
Depending on region and personal style, single-hung, double hung, casement, awning, slide-by, bay and bow windows are the most frequently used. A number of other style windows are frequently employed as accent windows.

How does a double hung window differ from a single hung window?
A double-hung window has two vertically moving sashes, each opening and closing a different part of the window. While a single hung window has only one moving sash, which is the bottom portion of the window.

What is a casement window?
A casement window is a window unit hinged at the side that swings outward, operated by a cranking mechanism.

What is an awning window?
An awning window is hinged at the top and swings out at the bottom to open, operated by a cranking mechanism.

What is a bay window?
A bay window is a series of usually three windows assembled in a polygon shape that projects outward from the side of a house.

How does this differ from a bow window?
Bow windows are very similar to bays, in that they also project from the side of a house. However, they are usually composed of a series of five window units assembled in an arc, rather than a polygon.

You mentioned that a number of special units are also available for use either separately or in conjunction with the units above. What are some of these units?
Many of these are special shapes. For example, they include hexagonal windows, round windows, half and quarter-rounds (which are exactly what the name implies), dormer windows, French windows (two casement sash hinged together to allow them to be opened into a confined space), lancet windows (tall narrow windows with a pointed arch top frequently used in Gothic architecture), and transoms, which are window units usually located above a door.

What are mullions?
Mullions are vertical members between window units. They are sometimes confused with muntins, which are secondary framing members that hold multiple panes of glass in the sash. Other parts of the sash include stiles (the outside vertical members) and rails (the top and bottom horizontal members).

I have heard windows referred to as lights, is this another type of window?
Lights (sometimes also spelled lites) are individual panes of glass within a window. Windows are usually designed/measured by the number of “lights” it has in each sash.

What are jambs?
Jambs are framing members used to support the window in the wall. Those framing members on the side are, logically enough, called side jambs. The framing member at the top is a head jamb. There are no jambs at the bottom. This framing member is referred to as a sill.

There are many general terms that I hear quite often, but some of them I do not understand. For example, what is a sash?
A sash, simply put, is the entire window, including the glass and the surrounding pieces that hold it together. The sash fits into a frame that is actually tied into the surrounding wall and holds the sash in place.

Why do my new insulated-glass windows "sweat" during cold weather?
Even the best-insulated windows can condense moisture from the air if the outdoor temperature is low enough and the indoor relative humidity is high enough. You're probably using a room humidifier or a humidification system connected with your furnace. Assuming that the windows were properly installed, try reducing the humidity setting during very cold weather.

Here are a few tips on reducing the moist air in your home:
- Use fans in bathrooms, kitchens and laundry rooms to circulate the air.

- Air out your home frequently by opening doors and windows.

- Reduce the number of indoor house plants, as plants increase humidity levels.

- Use a dehumidifier to remove excess humidity from the air.