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Thermo-Bilt Windows and Doors Glossary

All the industry terms simplified for you.

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Thermo-Bilt Windows and Doors Glossary

Industry-related most used terms explained.

Awning Window

A top-hinge window operated by a crank to open and close. Awning windows are commonly installed above or below other home windows, or above doors for extra ventilation and natural light.

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Bay Window

A combination of three windows that project outward from the wall of the house. These replacement windows are usually attached at 30- to 45-degree angles.

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The formation of moisture on or inside the window. Moisture that builds up on the exterior of the window is a normal byproduct of the weather; moisture between two panes of glass indicates a problem with the window or frame.


Heat loss through the window as a result of air moving between the window’s glazing.


When heat is lost through the window, typically through the edges of the glazing and/or the sash and frames.

Dead-Air Space

Space between the glass parts of an insulated glass unit.

Door Jamb

Each of the two upright parts of a doorframe, one of which the door is hung from.

Door Slab

A door panel minus the frame, sweeps, and lites.

Door Sweep

A simple weather-stripping system on the bottom of the door that keeps air and water from entering the home.


ENERGY STAR is the mark of high-efficiency products in Canada. The established symbol makes it easy to identify and choose the best energy performers on the market.

End Vent Window

A home window characterized by its fixed center sash, with two sliding outer sashes on either side. Best suited for areas where the outside space would be inconvenienced by the out-swinging window.

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Door Slab

A door panel minus the frame, sweeps, and lites.

Door Sweep

A simple weather-stripping system on the bottom of the door that keeps air and water from entering the home.


A window installer’s process of sealing glass to the sash. Double glazed window units are suitable for most homes, while triple glaze is recommended for colder climates.

I.G Unit

Insulating glass units are comprised of two or more lites of glass, separated by a spacer and then sealed at the edges of the glass.


A single unit of glass in a window.

Low E (Emissive) Glass

A thin metallic layer – just a few atoms thick – that’s applied to the glazing surface of a window. This element reflects energy back to its source (i.e. UV rays).

Patio Door

A glass exterior sliding door that opens and closes via adjustable tandem rollers. Available in two- or three-lite construction.

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The area of window holding the glass.


The horizontal section at the bottom of the window frame.

Slider Window

A window in which the sash moves horizontally. Available in two- or three-lite options. The latter includes operable end vents.

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Solar Heat Gain

Expressed as a percentage, the amount of heat gained from both sunlight and absorbed heat. The smaller the percentage, the better the window reduces solar heat gain, keeping the home cool and comfortable.


Material placed between pieces of glass that prevents sealant distortion, while keeping a uniform width between the glasses.

Steel Entry Door

A heavy exterior door made of steel that heightens home security, provides high thermal insulation, and needs no consistent maintenance.

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Storm Door

Strong exterior doors made to withstand heavy wind, rain, and other elements thrown at your home. Excellent security and ventilation.

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Choose from a wide variety of energy efficient replacement windows to suit the unique requirements of your Toronto home. As one of the few window companies in Toronto that utilizes Cardinal Glass, you can expect some of the best replacement windows in Toronto in terms of energy efficiency and value.

Tempered Glass

Glass that, if broken, will crumble into pebbles rather than shattering into large, dangerous shards.

Tilt Latch

A window mechanism that unlocks the sash, allowing the window to tilt in from the main frame.


The amount of heat transferred through a material. A lower U-value indicates a slower rate of heat flow, and therefore better insulation.


Material that creates a weather-proof seal around the operable sash of a window.


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The Thermo-Bilt Advantage

Over 20 years serving the Greater Toronto Area

 Equipped with a sturdy visibility screen for better airflow with an unobstructed view.  High-quality fusion welding on all corners for strong, insulating frames and sashes. Infrared-applied, white polyester warm edge seal for top thermal performance and smooth finish and energy efficient.

Lifetime warranty included. One of the few window companies in Toronto that uses Cardinal glass in all replacement windows and doors products; 7/8″ overall Cardinal I.G. sealed units. CSA rated. Available with self-cleaning Neat® glass.

Window installers will plan a Toronto window installation fit to your schedule. Custom awning window sizes and designs and materials available to suit your décor, including aluminum awning windows and vinyl awning replacement windows.

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