What are the major sources of Air Infiltration or Air Leakage in a building?

The amount of air leaking in and out of a building through cracks in walls, windows and doors. The lower a window’s air infiltration rating, the more airtight it is. A measure of the rate of air-leakage around a window, door, or skylight in the presence of a specific pressure difference. It’s expressed in units of cubic feet per minute per square foot of frame area (cfm /sq ft). The lower a window’s air-leakage rating, the better its airtightness. For more information go to this page.

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What are Argon and Krypton gases?

Argon and Krypton are odorless, colorless, non-toxic inert gases that can be used instead of air between panes of glass to increase insulation and energy efficiency. Argon is cheaper, more readily available gas, but Krypton is a better insulator and more expensive. Manufacturers often use Argon or a blend of Argon-Krypton to balance cost and performance.

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What is Condensation?

The deposit of water vapor from the air on any cold surface whose temperature is below the dew point, such as a cold window glass or frame that is exposed to humid indoor air. For more information about this physical phenomenon go to this page.

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What is Dew Point?

The temperature at which water vapor in air will condense at a given state of humidity and pressure.

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What is the meaning of Double Glazing?

In general, two thicknesses of glass separated by an air space within an opening to improve insulation against heat transfer and/or sound transmission. In factory-made double glazing units, the air between the glass sheets is replaced by Argon or Krypton gas or mixture of them and the space is sealed airtight, eliminating possible condensation and providing superior insulating properties.

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What is ENERGY STAR® Symbol?

The international ENERGY STAR® symbol is a simple way for consumers to identify products that are among the most energy-efficient on the market. Only manufacturers and retailers whose products meet the ENERGY STAR® criteria can label their products with this symbol. Choosing an ENERGY STAR® labeled product over a conventional model could save you hundreds of dollars in energy costs.

Canada and the United States have long been involved in the ENERGY STAR® program and utilize a zone default qualification schedule. For more information go to this page.

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What is Exterior Condensation?

Energy-efficient windows will occasionally have condensation on the exterior glass surface. This usually happens during periods of warm weather and high humidity near the time of sunrise. Because energy-efficient windows greatly reduce the amount of heat escaping to the outside (which is good during the long periods of cold weather), the exterior glass surface is cool enough to allow condensation to form for a short period of time.

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What is a Laminated Glass?

Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken. Used for safety glazing and sound reduction.

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What is Low-emittance (Low-e) Coating?

Microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U-factor by suppressing radiative heat flow. A typical type of low-E coating is transparent to the solar spectrum (visible light and short-wave infrared radiation) and reflective of long-wave infrared radiation. In other word Low-E stands for low-emissivity. Emissivity is a measure of how much a glass surface transfers radiant heat.

Glasses with this type of coating called Low e Glass. For more information about this type of glasses go to this page.

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What is Polyvinylchloride (PVC)?

An extruded or molded plastic material used for window framing and as a thermal barrier for aluminum windows.

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What does R-value represent?

The R-value represents the resistance a material has to heat flow. It measures the effectiveness of insulation in stopping heat flow. It measure of the resistance of a glazing material or fenestration assembly to heat flow. It is the inverse of the U-factor (R = 1/U) and is expressed in units of hr-sq ft-°F/Btu . A high-R-value window has a greater resistance to heat flow and a higher insulating value than one with a low R-value.

What is Relative Humidity?

The percentage of moisture in the air in relationship to the amount of moisture the air could hold at that given temperature. At 100 percent relative humidity, moisture condenses and falls as rain.

What is Solar Heat Gain Coefficient (SHGC)?

The fraction of solar radiation admitted through a window or skylight, both directly transmitted, and absorbed and subsequently released inward. It is expressed as a number between 0 and 1. The lower a window’s solar heat gain coefficient, the less solar heat it transmits, and the greater its shading ability. In other word, the lower SGHC, the better a product at blocking unwanted heat gain. SHGC can be expressed in terms of the glass alone or can refer to the entire window assembly. When cooling is needed, the key rating parameter is the SHGC. SHGC measures how well a product blocks heat from the sun. Blocking solar heat gain is particularly important during the summer specifically in warm areas. For more information go to this page.

What is a Tempered Glass?

Treated glass that is strengthened by reheating it to just below the melting point and then suddenly cooling it. When shattered, it breaks into small pieces. Approximately five times stronger than standard annealed glass; is required as safety glazing in patio doors, entrance doors, side lights, and other hazardous locations. It can’t be recut after tempering.

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What is a Tilt Window?

A single or double (hung or slider) window whose operable sash can be tilted into the room for interior washability.

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What is U-factor (U-value)?

A measure of the rate of non-solar heat loss or gain through a material or assembly. It is expressed in units of Btu/hr-sq ft-°F (W/sq m-°C). The U-factor may be expressed for the glass alone or the entire window, which includes the effect of the frame and the spacer materials. The lower the U-factor, the greater a window’s resistance to heat flow and the better its insulating value. It is the inverse of the R-value (U = 1/R). The U-factor describes how well a product prevents heat from escaping a home or building. When heating is needed, the key rating parameter is the U-factor. The rates of U-factor generally fall between 0.2 and 1.2. The lower the U-factor the better a product is at keeping heat in. U-factor is particularly important during the winter heating season.

What is a Weather stripping?

A strip of resilient material such as rubber or soft PVC for covering the joint between the window sash and frame or door gaps in order to reduce air leaks and prevent water from entering the structure.

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What is Weep Hole?

A small opening in a wall or window sill member through which water may drain to the building exterior. You should not fill weep hole between bricks. The path behind the weep hole in your windows or patio door should be cleaned regularly.

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