When deciding on your replacement windows and which company to purchase from, it is always helpful to be able to understand their unique language. The glossary of terms that follows provides some of the common terms associated with replacement windows that you may encounter when reviewing companies and products.

A

Air Chambers

Small honeycomb spaces within the sash and frame which help to insulate and strengthen the window

Air Infiltration

The amount of air that passes between a window sash and frame. In windows it is measured in terms of cubic feet or air per minute, per square foot of area. The lower the number, the less air the window lets pass through.

Air Latch

Latch mechanism on the interior face of the sash that retains the window in a partially open position for ventilation.

Argon Gas

An odorless, colorless, tasteless, nontoxic gas which is six times denser than air. It is used to replace air between the glass panes to reduce temperature transfer.

Awning Window

A hinged window that swings outward from the bottom for ventilation.

B

Bay Window

An angled combination of three windows that project out from the wall of the home. The windows are commonly joined at 30- or 45-degree angles.

Beveled Exterior

An angled extension from the frame that adds an aesthetically-pleasing dimension to the exterior of the window.

Bow Window

An angled combination of windows in 4- or 5-lite configurations. The windows are attached at 10-degree angles to project a more circular, arced appearance.

Butyl

A rubber material that seals the glass to the spacer, creating an airtight and watertight IG unit. Butyl has the lowest gas permeability of all rubbers.

C

Casement Window

A window with a side-hinged sash that swings out from either the right side or the left side for ventilation

Center of Glass U- and R-values

The U- and R-values measured from the center of the glass to 2-1/2" from the frame. Condensation Resistance Factor A measure of the effectiveness of a window or glazing system to reduce the potential for condensation. The higher the condensation resistance factor, the more efficient the window and glazing system.

Conduction

Energy transfer from one material to another by direct contact.

Convection

Heat transfer by currents that flow from a warm surface to a colder one.

Capping

An extension from the frame that adds an aesthetically-pleasing dimension to the exterior of the window.

D

Dead-air space

The space between the panes of glass of an I.G. Unit.

Double Hung Window

A window that has two operable sash which slide vertically.

Double-strength Glass

Glass with a thickness of approximately 1/3".

E

Egress Code

The code that requires a minimum opening of a window for persons to exit or firefighters to enter a building.

ENERGY STAR?

ENERGY STAR? is an independent U.S. government program establishing a standard set of guidelines to recognize the energy efficiency of various products. ENERGY STAR? guidelines are used in conjunction with a variety of building materials, including windows and patio doors. Over the past ten years, ENERGY STAR? guidelines have helped double the efficiency of windows they endorse

F

Fusion-welded

The process of joining materials by melting them together with extreme heat (over 500F), resulting in the materials uniting into a one-piece unit.

G

Glass

An inorganic transparent material composed of sand (silica), soda (sodium bicarbonate), and lime (calcium carbonate) with small quantities of alumina, boric or magnesia oxides. Available Styles: Clear, Bronze, Grey and Tinted. ? Glazing - The process of sealing the glass to the sash.

Glazing Bead

A strip of vinyl which surrounds the edge of the glass and holds it in place in the frame/sash..

Grids

Decorative horizontal or vertical bars installed between the glass panes to create the appearance of the sash being dividing into smaller lites of glass

H

Header

The horizontal top portion of the main frame.

Haze

Haze is the percentage of transmitted light which in passing through the speci­men deviates from the incident beam by forward scattering. In essence, the higher the haze value, the poorer the product is for clarity. The haze % for Low E2 is 0.14 as compared to any­where from 0.74 up to 1 .40 for pyrolytic Mid-E coatings.

I

I.G. Unit (Insulating Glass Unit)

Two or more lites of glass separated by a spacer and hermetically sealed at the glass edges.

Interlocking Channel

The horizontal/vertical sections of a pair of sashes that meet when the sashes are closed.

J

Jamb

The tent depth or thickness.

K

Keeper Rail

Vertical recessed portion.

L

Laminated Glass

Two or more pieces of glass bonded together over a plastic interlayer.

Lift Rail

A handhold for raising and lowering the sash. Rail implies that the handhold is continuous across the sash.

Lite

A unit of glass in a window.

Lock Rail

The horizontal/vertical section of the sash where the cam lock is attached.

Low E Glass

Low E glass stands for Low Emissivity Glass. This type of glass coating was developed to provide improved solar heat gain coefficient performance.

Low E2 Glass

Low E squared was developed to provide better summer daytime per­formance with only a slight reduction in visible light transmittance. Because of the excellent win­ter nighttime and summer daytime performance of Low E2, it is becoming the popular choice for many residential window applications. .

M

Main Frame

The head, sill and jambs sections of a window.

Mechanically Fastened Frame

Refers to frames fastened with screws.

Mesh

Fabric made of either fiberglass or aluminum, used in the making of screens.

Mullion

A vertical or horizontal connecting unit between two or more windows.

N

Nail-Fin

An extrusion attached to the main frame of a window used to secure the unit to the rough opening.

O

Obscure Glass

Glass that has been made translucent instead of transparent.

P

Patio door

A glass door that slides open and close on adjustable brass rollers. Available in 2-3 or 4 lite configurations with the operable panel available in any position.

Picture Window

A window that has no moveable sash.

Pull rail

A handhold for sliding the sash back and forth. Rail implies that the handhold is continuous across the sash.

R

R-value

Resistance a material has to heat flow. The higher the R-value, the greater the resistance.

Radiation

Wave energy transmitted directly from one object to another through the atmosphere or through transparent or translucent materials. The energy radiated is transmitted, absorbed, reflected or a combination of all three.

S

Sash

The part of the window which contains the glass.

Sill

The horizontal, bottom section of the main frame.

Sill Extender

An extrusion that is attached to the bottom of the window to cover the gap between the sill and the rough opening.

Single Hung

A window in which one sash slides vertically and the other sash is fixed.

Single-strength Glass

Glass with thickness between 0.085 and 0.100 inches.

Slider Window

A window in which the operable sash(es) move horizontally. Sliders are available in a 2 or 3 lite configuration, with the 3 lite having operable end vents.

Solar Heat Gain Coefficient (SHGC)

The fraction of incident solar radiation which enters a building as heat. It is based on the sum of the solar energy transmittance plus inwardly flowing fraction of absorbed solar energy on all lites of the glazing. It can be expressed in terms of a window or the glazing alone.

Solar Energy Transmittance

In the solar spectrum, the percentage of ultraviolet, visible and near infrared energy from the sun that is transmitted through the glazing.

Spacer

Material placed between two or more pieces of glass in order to maintain a uniform width between the glass, and prevent sealant distortion.

Spiral Balance

Device for holding vertically sliding sash in any desired position through the use of a spring or weight to counterbalance the weight of the sash.

Sputtered Coatings (Soft Coat)

This is how Low E2 is made. The advantage of this coating is that it provides overall qualities of high visible light transmission, neutral color, coating uniformity and low emissivily. This combination provides a nearly invisible coating with the highest level of performance possible.

Solar Energy Reflectance

In the solar spectrum (300 to 2500 nanometers), the percentage of ultraviolet, visible and near infrared energy from the sun that is reflected from the glazing surface(s).

T

Tape Glazing

Two-sided tape used to secure and seal the glass to the sash.

Tempered Glass

Glass with a surface compression of not less than 10,000 psi, or an edge compression of not less than 9,700 psi. When broken, the glass breaks into pebbles instead of shards.

Tilt Latch

Mechanism that unlocks the sash and allows it to tilt in from the main frame.

Tilt-in/lift-out sash

A sash that can be tilted to the interior and removed for cleaning and is manufactured by welding.

Trapezoid

Specially designed windows with geometric shapes .

U

U-value

Amount of heat transferred through a material. The lower the U-value, the slower the rate of heat flow and the better the insulating quality.

uPVC

Unplasticized Vinyl Chloride.

V

Vinyl

Generic term for Polyvinylchloride or PVC, an extruded material used for window and door framing.

W

Weather-stripping

Nylon material..

Weep Holes

Slots or holes in the sill (bottom) member of the sash frame that provides an outdoor release of infiltrated rainwater.