A

Air and Water Infiltration

The amount of air and water that passes between a window sash and frame. With windows, it’s measured in terms of cubic feet of air per minute, per square foot of area. The lower the number, the less air the window allows through.

Air Chambers

Small, honeycomb spaces within the sash and frame, which help insulate and strengthen the vinyl window.

Argon Gas

Argon gas is commonly used in windows as an insulating material to enhance energy efficiency. It is a colourless, odourless, and non-toxic gas that is denser than air.

Astragal

The central member of a double door, attached to a fixed or inactive door panel.

Awning Window

An awning window is a top-hinged window you crank to open outward from the bottom, with the top edge fixed in place, resembling an awning when opened. This design allows for ventilation while keeping rain and debris out, making it ideal for areas where airflow is needed but protection from the elements is a concern. Awning windows are often installed above or below other windows, or above doors in basements, bathrooms, or over sinks, where space may be limited, but natural light and ventilation are important.

Balance System

A device that holds a vertically sliding sash in any desired position. Its main functionality is counterbalancing the weight of the sash during opening and closing.

Bay Window

Large windows that come in angled sections; the middle pane is fixed, while some models feature outer panes that open up for airflow. Bay windows are often found in living areas; they are inviting, create depth, and can significantly increase the amount of light that a room receives. These windows are large and often feature inner ledges that can be decorated.

Bow Window

A bow window is a curved, multi-panel window structure that extends outward from a home’s exterior wall, creating a rounded appearance. It typically consists of four to six connected window panels arranged in a gentle curve and joined at a 10-degree angle. This design creates a panoramic view of the outside and allows more natural light to enter the room from multiple angles.

Brick Mould

A brick mould is an exterior (milled) trim or casing that surrounds the outer edge of a window or door frame, filling the gap between the frame and the exterior wall. Traditionally used in brick homes, it serves as a transition piece between the window or door and the surrounding brickwork, but it is also found in homes with siding or stucco exteriors.

Bronze-Tint Glass

Glass tinted with a light bronze colouring, which reduces the amount of light allowed through the pane.

Butyl Rubber

Butyl rubber is a synthetic combination or polymerization of 98% isobutylene and 2% isoprene. It offers physical durability, low gas and moisture permeability, and shock absorption. This material also resists aging, ozone, weathering, water, chemicals and heat. Its high adhesive level allows butyl rubber to stick on surfaces like glass, wood, plastic, aluminum, and galvanized metal even during low temperatures. Contractors favour butyl rubber due to its diverse applications, which include vehicle improvements, household repairs, and window sealing.

Cam Lock and Keeper

A mechanism that pulls the sash together when placed in the locked position.

Caming

A grooved, usually H-shaped, rod of cast lead used to hold window panes or pieces of glass together.

Capping

Cosmetic covering, usually found on the exterior of a window or door for aesthetics, or to integrate the window or door system into a building surface or weatherproofing system. Also known as ‘cladding’. Usually made of aluminum.

Casement Window

A casement window is an operable window with one or more hinges attached to its one side and the window frame. Contractors usually fit this in single or double panels and install hinges on its left or right side, making it possible to open outwards or inwards to the left or right. This window type is also known as a crank window because of its crank, cam, or lever handle that turns or operates the supporting arm of the window.

Caulk

Sealing cracks and joints around window and door frames to prevent air and water infiltration.

Caulking

Caulking means sealing gaps between components and materials using caulk—a flexible sealant made up of latex, silicone, rubber, or any polymer combination. Its consistency prevents water, air, dust, and insects from entering quarter-inch-wide gaps, making it a good choice for securing windows, doors, plumbing, and more.

Centre of Glass - U-values and R-values

U-values and R-values, measured from the center of the glass to 2-1/2″ from the frame.

Conduction

Transmission of energy (heat and cold) through a solid material via direct contact.

Convection

Window convection is a cyclical heat transfer process in which the hot air from a heating source comes into contact with the cold glass of the windows. Upon contact, the warm air loses heat, gains density, and sinks into the floor. The heating source sucks the now-cooled air, heats it, and releases it into the room, repeating the cycle.

Cladding

Cladding is a protecctive material applied to the outside faces of doors and windows (exterior skin), providing a durable, low-maintenance exterior surface. Typically made from materials like aluminum, vinyl, or fiberglass, cladding acts as a shield for the underlying structure, preventing damage from moisture, UV rays, and temperature changes. This added layer helps extend the life of the window or door while reducing maintenance needs.

Dead-Air Apace

The space between the panes of glass of a sealed unit.

Deadbolt

The locking mechanism installed on entry doors. It features a throw (the bolt) that locks into place within the frame. Deadbolts provide greater security than standard door locks, as they are very difficult to open through forced entry.

Desiccant

A desiccant is a moisture-absorbing material used to remove humidity from the air or enclosed spaces. In window manufacturing, desiccants are often found inside the spacer bars of double or triple-pane insulated glass units (IGUs). Their primary function is to prevent condensation from forming between the panes by absorbing moisture from the air trapped within the sealed unit.

Divided Lite

A window with a number of smaller panes of glass, separated and held in place by muntins.

Door Jamb

A door jamb is an essential component of a door frame, providing structural support and a stable base for the door itself. It is the vertical portion of the door frame that runs alongside the edge of the door and helps to hold it in place when closed. The door jamb is crucial for maintaining the integrity and functionality of the door, ensuring it fits securely within the door frame and opens and closes smoothly.

Door Slab

A door panel without lites, a frame, or sweeps installed.

Double Glazed Units

Units consisting of two lites of glass, and one air space in between.

Double Glazing

Double glazing—also known as a double pane—refers to a window with two glass panes separated by a spacer bar, creating a thin gap to be filled by air or an insulating gas. This window type became standard in homes in the 1970s because an insulation layer provides better temperature regulation, noise reduction, and security.

Double Hung Window

A double-hung window is a type of window with two movable sashes that slide up and down within the frame. Both the upper and lower sashes can open, allowing for versatile ventilation. This design differs from single-hung windows, where only the bottom sash is operable.

Dry Glazing

An alternative method of placing glass in a door or window. Dry glazing is recommended whenever reflective coatings are glazed on the first surface.

Dual-Durometer

A material that has two or more levels of flexibility. An example is the weather stripping used between the frame & sash of a casement window.

Door Sweep

A door sweep is a weather-stripping system installed at the bottom of a door that prevents air and water from passing under the door. It seals the gap between the door and the floor, serving as a barrier against drafts, dust, pests, and even noise, helping to improve a room's insulation and overall comfort. Door sweeps are especially useful in exterior doors or doors that lead to unconditioned spaces, such as basements or garages, where maintaining a tight seal is important for energy efficiency.

Dormer

A dormer is a structural element that protrudes vertically from the sloped roof of a house, typically including one or more windows. Dormers are used to increase the usable space in the upper levels of a building, such as attics or lofts, by adding headroom and natural light. They are often seen in traditional or colonial-style homes, but modern designs also incorporate dormers to enhance architectural character and functionality.

Easy-Clean Glass

A specialty option that can be applied to the glaze; refers to the coating that helps prevent moisture and grime buildup. Rain that comes into contact with these windows will be sheeted off. This option is recommended for high up or hard to reach units.

Egress

Egress means “the act of going out,” “the right to go out,” or “the means of going out.” In architecture, this term refers to an exit or escape route for building occupants in case of an emergency. Building codes require egresses placed strategically in different areas of a residential home, ensuring everyone inside has quick and easy access to emergency exits.

Egress Code

The code that requires a minimum opening size of a window for people to exit, or for firefighters to enter.

Egress Window

A window with an opening size as required by the local building code, to allow occupants to escape through the window in case of a fire.

Electronic Deadbolt

A type of deadbolt that features an automatic locking system. Electronic models come equipped with keypads that can store a number of code combinations for user convenience. They can be programmed to automatically lock when you leave your home, too. They feature all the same hardware as traditional deadbolts; the throw is released electronically, although it can be manually turned as well.

Emissivity

The measure of a material’s effectiveness in emitting thermal energy. In the case of glass, it refers to its ability to cool itself from sources of heat, such as the sun.

End Vent Slider

A window that features a fixed center sash, flanked by two sliding outer sashes. The sliding panes can be tilted inward for cleaning purposes; these windows are perfect for ventilating spaces. They are best suited where outside space would be compromised by an out-swinging window.

Energy Efficiency

Energy efficiency refers to using less energy to do more. For example, LED (light-emitting diode) and CFL (compact fluorescent lamp) lightbulbs are energy-efficient products that illuminate your homes as effectively as their incandescent counterparts while using significantly less energy to do so.

ENERGY STAR®

The ENERGY STAR® label signifies that a product, such as appliances, electronics, windows, and more, meets of exceeds energy efficiency guidelines set by the Environmental Protection Agency (EPA) in the United States. This label indicates that the product has undergone testing and verification to demonstrate its ability to significantly reduce energy consumption without compromising performance.

Entrance Door

An entrance door is the primary door used to access a home, commercial building, or other structure from the outside. It serves as a point of entry and exit while also providing security, insulation, and aesthetic appeal. Entrance doors are typically larger, stronger, and more decorative than interior doors to create a welcoming first impression and enhance curb appeal.

Exact Window Size

The dimensions of a window or door unit measured along the outside of the frame.

Exterior Stop

The removable glazing bead that holds the glass or panel in place when it’s on the exterior side of the light or panel.

Extrusion

Extrusion is a manufacturing process in which a material, such as metal, vinyl, or plastic, is pushed through a die to create continuous shapes with a consistent cross-section. This process is widely used to produce window and door frames, as well as other building materials like pipes, siding, and weatherstripping.

Failed IG Unit

An insulated glass unit failure is the industry term for permanent material obstruction of vision through the unit, due to the accumulation of dust, moisture, or film on the internal surface of the glass.

Fenestration

Fenestration refers to the arrangement and design of openings in a building, including windows, doors, and skylights. In Latin, "fenestra" means a small opening or pore in an anatomical structure and directly translates to "window."

Fiberglass Doors

These doors are very durable and have a place in most households. They have the beauty of hardwood, but are not subject to dents, cracks, or splitting. The paneling designs on fiberglass doors can be custom-tailored for a unique finish!

Fire Rated Doors

Fire rated doors are specially designed doors that can resist the spread of fire, smoke, and heat for a specified amount of time. These doors are constructed in such a manner to pass ASTM E-152 fire tests and have identifying labels from qaulified testing and inspection agencies. They are typically rated to resist fire for 20, 45, 60, or 90 minutes. These doors are crucial for maintaining the safety of occupants and providing extra time for evacuation during fire emergencies. Fire-rated doors are often required in commercial buildings, apartment complexes, and certain residential areas like garages and basements.

Fixed Window

Windows that do not open; they feature a thinner frame and larger glass pane for maximum viewing space. ‘Picture windows’ can be installed anywhere; they provide maximum energy-efficiency due to the lack of an opening system, and are a great choice when you need to brighten a dark or small space.

Flanker

The designation given to units that flank a center picture unit in a double or triple combination window.

Flashing

Flashing is a crucial element in window installation designed to prevent water infiltration and moisture damage. It's a thin, flexible material, often made of metal, plastic, or rubber, applied around the perimeter of windows. Flashing serves to create a barrier that directs water away from the vulnerable areas where window meets the wall.

Flat Glass

All types of glass (rolled, float, plate, etc.) manufactured in a flat form, regardless of the method of production.

Float Glass

Float glass—also known as flat glass—is produced by floating molten glass on a bed of molten metal (typically tin).

Frame

The enclosure in which the window sash or door panels are mounted. Refers to the part the sash fits into (head, jambs and sill).

French Doors

French doors are hinged doors with glass panels spanning their length. They can have thick frames on the top and sides or grid patterns separating each panel.

Full Screen

A screen which covers the entire opening of a window.

Fusion-Welded

The process of heating mitered corners to 2008°F, bringing the heated corners into contact until they fuse together into a single piece of vinyl.

G

Gas-Filled Units

Insulating glass units with a gas other than air (usually an inert gas, such as argon) in the airspace between the panes. This is done to decrease the unit's thermal conductivity (U-value) and increase the unit's sound insulating value.

Gas Fillings

Refers to the type of gas that is present between the panes of glass. Argon and krypton fillings are used often, as they slow down the heat transfer inside the glaze. This increases the energy-efficiency of the window better than windows that contain air.

Gasket

A window gasket is a sealing tool found around the window pane to prevent air and water leakage. It’s a rubber, silicone, neoprene, or felt material you’ll find lodged within the edges of stationary and viewing windows in various applications, such as residential, commercial, and industrial. Its insulating properties prevent outside noise from entering your home and keep hot and cold air from escaping, lowering your heating and cooling costs.

Geometric

Geometric windows are specially-designed, custom-shaped windows with unique, non-standard forms like circles, triangles, arches, hexagons, and more. Unlike traditional square or rectangular windows, geometric windows add visual interest and architectural character to homes and buildings. They are often used as accent windows to enhance design elements or fill unused wall spaces.

Glass

The pane that sits inside the frame.

Glazing

The process of sealing the glass to the sash. This can also refer to the number of panes that are present in the window. You can choose from double or triple glazed options; the latter is recommended for very cold climates, but most homes are suited for double glazed units.

Glazing Stop

The part of the sash or door panel which holds the glass in place.

Gliding Window

A window that opens horizontally; the panels slide left and right on a built-in track. Gliding windows are great space-savers and can be opened and closed with ease. They are recommended for use as an emergency escape window, due to the speed at which they can be opened.

Grills

Window grills are vertical or horizontal bars placed in between window panes to create a unique look and give your home an attractive appeal. Installing these in your windows creates an illusion that the glass is divided into smaller individual panes.

Half Screen

A screen which does not cover the entire opening of a window. Used on the bottom half of single hung units, and on the operating sash of single sliders.

Head

The horizontal top portion of a window or door frame.

Head Expander

An individual U-channel installation accessory that may be fitted to the head of a replacement window; accommodates differences between opening and window heights.

Header

A header is a structural beam or horizontal support installed above windows, doors, and other openings in a wall. Its primary purpose is to distribute the weight from above the opening to the surrounding wall, ensuring the structural integrity of the building. Without a header, the wall would be unable to support the load, causing sagging, cracks, or collapse.

Hinge

Hinges are mechanical hardware that connect two objects and allow them to rotate at a limited angle. It consists of three parts: two leaves, one knuckle and one pin. Leaves are flat metal surfaces screwed to the objects to connect and move with them, while the knuckle, a hollow circular joint where the pin is inserted, allows them to rotate.

Hinge Mortise

The area cut away to accept the hinge leaf, for mounting on a door frame or door edge.

Horizontal Slider

A window with movable panes that slide horizontally.

Hard Water Stain

A hard water stain on glass is a blemish on a glass surface created by water or other solutions. When water with a high mineral content evaporates from glass surfaces, it leaves behind a cloudy, white residue that can build up over time, resulting in a dull or dirty appearance. These stains are common on shower doors, windows, and outdoor glass fixtures exposed to rainwater or sprinkler systems.

I.G. Unit (Insulating Glass Unit)

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

Infiltration

Air infiltration in windows refers to the differences between outdoor and indoor air pressure and pushes it to flow through the small gaps between the sash and frame. The exchange of outdoor and indoor air causes stress on heating and cooling systems, making them inefficient.

Interlock

A design feature that enables sashes to engage one another when closed.

Internal Grills

Grids mounted between the two panes of glass of an insulated glass unit.

J

J-Channel

Integral extension on the outside of a new window that eases installation on siding applications.

Jamb

"A jamb is the side post or lining of a doorway or window that makes up a door or window frame. It consists of two parts: head and side jambs. These structurally support the door or window panels and ensure they stay securely within the framing. They also feature soundproofing, insulation, and aesthetic improvements.

Jamb Extensions

Flat parts made of vinyl, wood, or other materials, which are attached to the inside edges of a window jamb to extend its width to adapt to thicker walls.

K

Keeper

The part of a window lock, mounted on an opposing surface of the window, that the lock arm locks under or into. Pulls the sash into a locked position, and fully releases it when opened.

Knocked Down

Not assembled; parts for a window or door frame, pre-manufactured for assembly at a later date on the job-site.

Krypton Gas

Yes, krypton is used in double and triple-pane windows as an insulator.

Laminated Glass

Laminated glass is a safety glass comprising of two or more layers of panes stuck together by thin polymer interlayers. Consumers can choose from a variety of colours and thicknesses to achieve the desired appearance and performance. Regardless of customization, laminated glass withstands great pressure because of the strong support formed by the multiple panes and interlayers. Massive brute strength would be needed to break through the surface. When broken, the glass cracks and forms a spider web pattern to minimize harm to anyone nearby.

Lift Handle

A handhold for raising and lowering the sash. ‘Handle’ indicates that the handhold is not continuous across the sash.

Lift Rail

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

Lineal Footage

Lineal footage, also known as linear footage or linear feet, is a unit of measurement that quantifies length. It measures one dimension of an object in a straight line, in contrast to square feet, which measure two dimensions: length and width. One linear foot equals 12 inches or one foot.

Lite

A unit of glass in a window or door.

Low E Glass

Low emissivity glass—Low-E glass for short—is a pane designed to minimize the amount of infrared and ultraviolet rays passing through the surface. Its thin, transparent coating made of metallic oxide deflects dangerous rays while allowing light to enter.

Lintel

A lintel is a horizontal structureal support above a window or door opening that bears the weight of the wall above. Lintels are essential in construction, as they help distribute the load evenly, preventing the opening from collapsing or becoming distorted over time. They are commonly made from materials like steel, stone, or reinforced concrete, depending on the building’s design and load requirements.

Main Frame

The head, sill, and jamb sections of a window.

Masonry Opening

The space in a masonry wall left open for windows or doors.

Mechanically Fastened Frame

Window and door frames fastened with screws.

Meeting Rail

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

Mesh

Fabric made of fiberglass used in making screens.

Mullion

A mullion is an architectural device designed to create sections on windows or doors. This integral part of a window or door acts as vertical or horizontal support and creates divisions for multiple pieces of glass and panels.

Multi-Point Locking

A term used for locking hardware that engages a window sash to the frame at multiple locations with a single throw of an operator.

Muntin

A muntin—also known as a muntin bar, glazing bar, sash bar, or grille—refers to the vertical or horizontal wooden or steel dividers in a window.

Nailing Fin

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

Night Latch

Hardware which, when extended, restricts the sash opening to a predetermined dimension.

O

Obscure Glass

Glass that has been made translucent instead of transparent.

Operable Window

A window that can be operated for ventilation.

Operating Panel

In a two-panel window or door, the panel that swings or slides open.

Operator

Crank-operated device used to open and close casement windows.

P

Pane

A pane, or window pane, typically refers to a transparent, flat, and even surface of glass inside a window or door frame. It allows light to shine through, brightening your interiors and warming up spaces during the day. Its variations include a single large sheet, a shaped pane, or multiple panes separated by muntins. They also come in single, double, and triple variations, indicating the number of glass sheets present in the window frame, an element that dictates the window's energy efficiency rating.

Panel (Door)

A door panel, also known as a slab, is the whole part that swings back and forth. In sliding glass doors, it's the entire part that slides or stays in position.

Patio Door

A glass door that slides open and close on adjustable tandem rollers. Available in 2, 3, and 4 section configurations.

Picture Window

A picture window is a large, fixed window that does not open or close. It is designed to provide an unobstructed view of the outdoors, much like a picture frame showcasing a landscape. Picture windows maximize natural light, enhance scenic views, and create a sense of openness in living rooms, dining areas, and other large spaces.

Pivot Bar

A metal post attached to a moving sash and seated in a balance shoe that allows the window sash to tilt.

Privacy Doors

These doors feature special glass designs that prevent people from peeking through them. They work great as entry doors, as the bevel designs are attractive yet functional.

Pull Handle

A handhold for sliding a sash back and forth. ‘Handle’ implies that the handhold is not continuous across the sash.

Pull Rail

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

PVC

Polyvinyl chloride, also known as PVC or vinyl, is a thermoplastic polymer widely used in windows and doors but can also be used in pipework, cable insulation, and medical devices. It’s the third most popular thermoplastic by volume after polyethylene and polypropylene due to its impressive properties—lightweight, durable, and easy to process.

Quarter Round Window

Stationary or operating window shaped as a quarter circle.

R

R-Value

R-value, or “resistance value,” is a measure of the thermal resistance of an insulating material. It quantifies the material's ability to resist the flow of heat from one side to the other. A higher R-value indicates better insulation performance.

Radiation

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

Relative Humidity Condensation Point

The relative humidity level at which visible water vapor or other liquid vapor begins to form on a cold surface. If the temperature changes, but no water vapor is added or taken away, then the relative humidity will also change, increasing as the temperature falls. The relative humidity will continue to rise with falling temperature until the dew-point is reached – or, the temperature at which the relative humidity becomes 100%.

Replacement Window

A window that is designed for and subsequently installed after the removal of all or part of a previously-installed window.

Retrofit

Adding or replacing items not provided at the time of original construction. Common retrofit products include replacement doors and windows, insulation, storm windows, caulking, weather-stripping, vents, and landscaping.

Reveal

The edge of a door or window jamb not covered by the casing.

Roll-formed Screen Frame

A method of fabrication in which material (vinyl) is placed on a machine, where the material is formed into shape using differently shaped rollers and pressure.

Rough Opening

A rough opening is a vacant space cut out of a wall where a window or a door will eventually be installed. Contractors create a large gap with precision so homeowners won’t have difficulty determining the window or door frame size they'll later need. Its precise measurements—width and height—are usually larger than the frame to grant room for a secure installation.

Retrofit Windows

Retrofit windows, also known as replacement windows, are specially designed to fit into an existing door or window frame without requiring major construction or alteration to the surrounding wall. Common retrofit products include replacement doors and windows, insulation, storm windows, caulking, weather-stripping, vents, and landscaping.

Safety Glass

A strengthened or reinforced glass that is less susceptible to breakage or splintering.

Sand Blasting

Sand blasting, also known as abrasive blasting, is a process used to clean, strip, or shape surfaces. This technique smoothens rough surfaces at high speeds using abrasive particles, such as sand or glass beads. This process effectively removes any impurities, old coatings, or imperfections from the surface, creating a clean and textured finish.

Sash

The components that hold a window glass in place inside the frame.

Sash Lift

A window sash lift is a handle attached to single-hung or double-hung windows after installation. Also known as a sash handle or window pull, it allows easy opening and closing of hung windows, making it ideal for people with limited mobility or strength. There are three types of window sash lifts that vary in size: bar, hand, and finger lifts.

Sash Stop

A molding that covers the joint between window sash and the jamb.

Screen

A window screen is a mesh cover for windows, allowing air to flow indoors while keeping debris, animals, and bugs out. It can be used for residential or commercial applications, especially when you want to add ventilation inside the building. Window screens can be made out of aluminum, fibreglass, polyester, stainless steel, or copper-bronze and brass. They also come in different types: standard, solar, retractable, and specialty screens.

Sealant

A sealant is a flexible, adhesive material used to close gaps, joints, and cracks to prevent air, water, dust, and other elements from entering a space. In window and door installations, sealants are essential for creating a weatherproof, airtight, and watertight seal between the window frame and the surrounding wall.

Side Lite

A side lite is a narrow, vertical window installed on the side of an entry door. It's usually built within the door frame and can be placed either on one side or both sides of the door. Side lites can also come with transom windows that sit above the entire door and the side lites to bring more light into the entryway.

Sill

A sill, also known as a window sill, is the horizontal, bottom-most part of a window frame. It supports the window structure and helps direct rainwater away from the wall below, preventing water damage and moisture infiltration. Sills can be found on both the interior and exterior sides of a window.

Simulated Divided Lite

A method of constructing windows in which muntins are affixed to the inside and outside of a panel of insulating glass, simulating the look of a true divided lite.

Single Hung

A window in which one sash slides vertically, and the other sash is fixed. Generally, the bottom sash is the operable one.

Slab (Door)

A slab door, also known as a blank door, is the door itself; it doesn’t have a frame, hinges, or doorknobs. In other words, it’s the bare version of a pre-hung door unit.

Sloped Sill

The sill of the window that has a downward slope to the outside, to assist in excessive rainwater runoff.

Solar Heat Gain Coefficient (SHGC)

The Solar Heat Gain Coefficient (SHGC) refers to the measurement of solar energy transmitted through the window, and it also indicates how well the window blocks heat from the sun. The scale for SHGC ranges from 0 to 1, with standard values sitting between 0.25 and 0.80. A lower value means less heat passes through the window.

Spacer

Window spacers are essential components in double or triple-pane windows. They are typically made of aluminum or silicone and are positioned between the glass panes, creating a sealed space. These spacers serve multiple critical functions, such as maintaining the appropriate gap between the glass panes, preventing them from touching, and ensuring the insulating gas (like argon or krypton) remains sealed within the unit.

Stain

A blemish on a glass surface created by water or other solutions.

Stiles/Threshold

Stiles and thresholds are key structural components found in doors and window frames. Stiles are the vertical, side portions of a door or window frame, while thresholds are the horizontal pieces located at the bottom of a door frame. Together, they provide structural integrity, support, and weatherproofing for the door or window.

Stop

A trim member attached to the window frame, stopping the sash of a projecting window when closed to prevent it from swinging through the opening.

It also covers the perimeter crack between the sash and the window frame in double hung and sliding windows, and prevents the sash from coming out of the frame. Stops used at the top or bottom of the balance channel prevent the sash in hung windows from hitting one another when opened.

Stud

Studs are vertical framing members that provide support and foundation for indoor and outdoor walls as they require fasteners as their anchors to prevent them from lifting off the foundation during calamities. Buildings must have abundant studs to hold windows, doors, interior finishes, insulation, and utilities in place and provide shape to a room or building.

Shims

Shims are thin, wedge-shaped pieces of material (often wood shingles) used in construction and installation to adjust the alignment and fit of windows and doors. Shims are placed between the window or door frame and the rough opening to fill gaps and ensure a level, secure fit. They help prevent uneven installation, which could lead to drafts, water leaks, or even structural instability over time.

Square Foot

Square footage refers to the total area of a space, measured in feet, and is commonly used to describe the size of rooms, homes, or other structures. unit of measure for designating an area of one foot by one foot. It is calculated by multiplying width (in inches) by height (in inches) divided by 144 = area in square feet. In real estate, square footage is a key factor in determining the value of a property, as larger spaces tend to command higher prices.

Tape Glazing

Two-sided tape used to secure and seal the glass to the sash. Also known as 'wet glazing'.

Tempered Glass

Tempered glass is a type of safety glass processed and hardened by thermal or chemical treatments. It has various applications, including home windows, passenger vehicles, shower doors, and more. It’s four times tougher and stronger than a standard annealed glass, requiring extra power to smash it into pieces.

Thermal Break

A thermal break or barrier is a polyamide or polyurethane material with low thermal conductivity fixed on a window frame’s extrusion to reduce the flow of thermal energy.

Thermal Expansion

A change in dimension of a material as a result of temperature change.

Tilt Latch

A mechanism that unlocks the sash and allows it to tilt in for easy cleaning.

Tilt-In Sash

A sash that can be tilted to the interior for easy cleaning.

Tinted Glass

Glass with material added, giving the glass a light and/or heat reducing properties and colour.

Total Unit U-Values and R-Values

The heat lost by windows is expressed with U-values, or U-factors. U-values are the mathematical inverse of R-values. So, an R-value of 2 equals a U-value of 1/2, or 0.5. Unlike R-values, lower U-value indicates higher insulating efficiency.

Transom

A transom is a horizontal beam separating a door from a transom window placed above it, opposite the vertical mullion. This architectural feature is a popular customization choice, especially if you want to add flair to your house’s exterior. It can be as simple as a plain divider or as grand as a carved beam.

Transom Window

A transom window is a horizontal window installed above a door or larger window. It serves both decorative and functional purposes, allowing additional natural light and ventilation into a space. Transom windows are often used in entryways, living rooms, and bathrooms to increase brightness while maintaining privacy.

True Divided Lite

A term commonly used to describe the arrangement of grills in a single-sealed unit, giving the effect of divided lites (individual panes of glass in a single unit).

U

U-Value

U-value—also known as the U-factor—measures the amount of heat transferred through a material. Its unit of measurement is expressed in watts per square meter degree Celsius.

Ultraviolet (UV)

Ultraviolet (UV) light is a type of electromagnetic radiation that comes from the sun but can't be seen as visible light due to its short wavelengths, ranging from 10 to 400 nanometers. UV light is also present in tanning lamps, black lights, and electric arcs.

Vent

The operating portion of a window that swings in or projects out.

Venting Unit

A window or door unit that opens or operates.

Vinyl

Polyvinyl chloride (PVC), or vinyl for short, is an economical and versatile material used for multiple kinds of applications, such as construction, electronics, and automobiles. This synthetic resin comes from the polymerization of vinyl chloride. It comes in rigid and flexible forms—the rigid form is commonly used for construction and packaging, while the flexible option is for plumbing, electrical cable insulation, and musical records.

Vinyl Clad

A door or frame made of wood, with an exterior skin of vinyl.

Vinyl Window

A vinyl window is a type of window with a frame made from polyvinyl chloride (PVC), a durable, weather-resistant, and low-maintenance material. Vinyl windows are known for their energy efficiency, affordability, and ability to withstand harsh weather conditions without warping, peeling, or rotting.

Warm Edge Spacer

A non-conductive edge spacer found in insulating glass units, instead of the conventional aluminum (conductive) edge spacer. “Warm Edge” spacers may be made of butyl, silicone foam, or other non-metallic materials and sealants.

Weatherproofing

Weatherproofing, as it pertains to windows and doors, is the process of making them resistant to the effects of weather such as rain, wind, snow, and temperature spikes. It involves sealing drafts to prevent warm air from leaking out and cold air from entering. Other benefits include water leak resistance, reduced risks of mould formation, improved HVAC efficiency, and lower electricity bills.

Weatherstripping

Weatherstripping is a material or a combination of materials used to seal gaps and openings around doors, windows, and other openings in buildings to prevent the infiltration of outdoor elements such as air, water, dust, pests, and noise.

Weep Flaps

A vinyl flap covering a weep hole, which allows water to escape, while keeping insects out.

Weep Holes

Weep holes are small openings at the bottom of window frames that allow water to exit the frame, preventing it from collecting inside and causing permanent damage to the window structure. Vinyl, aluminum, steel, and fibreglass windows often allot ample space for weep holes. These materials have chambers that allow moisture to seep right into the frame. Tiny as they may be, these gaps play a vital role in maintaining your window’s health and appearance.

Weep Slots

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

Wet Glazing

A silicone-based substance used to secure and seal glass to the sash.

Window Frame

The primary purpose of a window frame is to hold the glass or glazing of a window securely in place within the opening of a building's wall. It provides a rigid structure that keeps the glass panels in position and prevents them from shifting or falling out. The frame also helps to seal the gap between the window and the wall, contributing to weatherproofing and insulation of the building. It plays a crucial role in the overall stability, functionality, and aesthetics of the window.

Window Glass

Window glass is the pane that sits inside the frame that allows light to enter while providing insulation and protection fromt the elements. It’s typically made from materials like tempered glass, which is heat-treated for added strength, or laminated glass, which consists of multiple layers for enhanced safety. Depending on the window's purpose, the glass can vary in thickness, style, and performance features, such as UV protection or noise reduction.

Window Glazing

Window glazing refers to the window glass or pane, the window glazing compound or putty, and the process of sealing the glass to the sash. All these optimize a home’s energy efficiency by adding extra insulation to the windows. However, in a general sense, manufacturers and window installation experts use the term “window glazing” to refer to pane types.

Window Hardware

Various devices and mechanisms for the window, including cords, chains, fasteners and locks, hinges and pivots, lifts and pulls, pulleys, sash weights, sash balances, etc.

Window Lites

Window lite are individual panes of glass within a window or door, separated by bars called muntins or mullions. Traditionally, lites were a necessity due to the limitations of glass manufacturing, where large sheets of glass were difficult to produce. To create larger windows, smaller panes, or lites, were combined within a frame. Today, while large sheets of glass are more readily available, window lites remain popular for their aesthetic appeal, offering a classic, divided look.

Window Sash

A window sash is a fundamental component of a window frame. It consists of the framework that holds the glass panes in place within the window opening. Sashes can be moveable or fixed, allowing for opening and closing. They're typically crafted from wood, metal, aluminum, or vinyl and may incorporate additional elements like grids or muntins for design and support.

Window Size

Size of the actual window frame; always expressed as width first, then height.

Window Style

The description of the way a window operates; example hung, sliders, casements etc.

Window Vent

A window vent is the operating portion of a window that swings in or projects out, allowing air to flow into or out of a space. It provides ventilation while maintaining the window’s security and energy efficiency. Commonly found in modern homes, window vents help regulate the indoor air quality by letting in fresh air and expelling stale or humid air. They are often used in rooms like kitchens, bathrooms, and basements where proper ventilation is essential to prevent moisture buildup and mold.

Window Reveal

A window reveal is the part of a window or door jamb that is not covered by the casing, remaining visible once the window is installed. It’s the section of the wall opening where the window fits, creating the transition between the window itself and the wall surface.

The reveal provides both a functional and aesthetic role in window installation, giving the window a finished appearance and contributing to its overall stability.

Window

A window is an opening in an external wall or roof of a building that allows light, air, and sometimes sound to pass through while providing views of the outside. The entire window unit consists of a frame, sash, glazing, and any operable elements. It is typically filled with transparent or translucent glass and framed by materials such as wood, vinyl, or aluminum. Windows come in various shapes, sizes, and styles, and they play an important role in the comfort, functionality, and design of a home or building.

Window Crank

A window crank is a mechanism used to open and close casement or awning windows by turning a handle. The crank system allows the window to swing outward or upward, depending on the window type, offering precise control over ventilation and air circulation. Window cranks are commonly found on casement windows, which are hinged on one side, or on awning windows, which are hinged at the top.

Glossary, Windows and Doors Installation in Toronto

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