Windows are the eyes to the soul of your house…or something like that. Windows are very functional – they allow daylight into the house and can be opened for a nice breeze on a spring day. They also help to keep out the rain, snow, extreme temperatures, and tiny critters when used with a screen.
Besides being functional they’re also an important part of your house’s personality. The type, size, and configuration of windows can make or break a home’s appeal.
In this article we’ll discuss everything windows, from how they’re put together, their types and shapes, the glass that goes in them, and other miscellany such as screens, storm windows, shutters, and other things you should consider when designing your house.
What Things are Called
Window components have their own unique terms. Below is a summary of the parts of a window unit. Words that are in bold text are also defined in this and following sections.
These windows are single-hung units, where the top sash is fixed and the bottom sash can raise up to open the window to the outside.
The upper sashes have divided lites.
The top rail of the upper sash is behind the raised window blinds, while the sill of the unit frame is unseen below the bottom rail of the sash. The sill that is seen is horizontal casing trim in front of the frame.
From photo taken by Craig Klomparens, courtesy Tilton, Kelley + Bell.
Casing
The visible material, typically wood, placed around a window to cover the gaps between the frame and the wall and that’s attached to the wall. This trim can be simple boards or boards with decorative profiles.
Frame
The material at the perimeter of a window unit in which the window components are placed. The frame is what attaches to the wall in which the unit is placed. A window unit is manufactured and shipped with its frame as the edges of the unit.
Below are the components of the Frame:
Head
The top frame piece of a window unit.
Jamb
The vertical frame piece on each side of a window unit.
Sill
The bottom frame piece of a window unit. The exterior sill is sloped downward to allow for drainage of rain water.
A sill can also be a horizontal trim piece added at the bottom of the window frame to extend a horizontal surface as part of the casing trim.
Also, a sill can be an exterior wood piece, a horizontal row of brick, or a piece of stone added below the window frame to account for wall thickness and wall material to ensure water drains away from the window.
Glass
As we all know, glass is the material we can see through to the outside (or inside if you’re nosy) or to another room.
Glass is typically clear, but can also be translucent, opaque, or reflective. Glass can be enhanced in its thermal and solar performance through the use of insulated glass along with gases and coatings integrated into it for improved performance. Glass can be decorative through the use of beveled glass, colored glass, patterned glass, stained glass, and textured glass. Glass can also be switchable from clear to opaque through the use of new technologies.
Below are elements and terms related to glass:
Divided Lite
A window that has smaller pieces of glass set in narrow frames (muntins) inside the larger sash or frame of the window.
Glazing
Glazing is the glass in a window or door unit, and is also the process of installing the glass or installing the window unit.
Insulated Glass
Two panes of glass of the same size attached on each side of an airtight frame. The vacuum, air, or gas, between the glass acts as an insulating barrier between the outside temperature and the inside temperature to assist in maintaining a comfortable temperature inside the house.
Today triple-pane insulated glass is available consisting of three panes of glass attached to two airtight frames, creating two layers of insulating air. This glass is used in environments with extreme temperatures.
Leaded Glass
A decorative glass pattern consisting of small pieces of profiled glass or glass pieces of different colors. The pieces are joined together using thin strips of lead or copper, and then inserted into a window sash or frame.
Lite
A lite is a single pane of glass or insulated glass within a window unit. A window unit can have one, two, or multiple lites depending on the type and design of the unit.
Muntin
Narrow frame members that subdivide a window unit or sash into smaller pieces of glass. Muntins are typically placed in a grid pattern of same-sized pieces of glass, but can sometimes be subdivided into panes of varying sizes and shapes to create a decorative pattern.
Hardware
The working components added to a window unit. These can include crank units for casement windows, hinges for operable units, handles to lift operable sashes, latches that close a window tight, counterweights or springs for movable sashes of single-hung or double-hung windows, and locks for operable units.
Operable Unit
A window that can open to allow outside air into the house.
Pane
The glass that fits inside a window lite. A single-pane unit is a window that uses a single piece of glass in its window lite(s). A double-pane unit has standard insulated glass in its window lite(s). A triple-pane unit has triple-pane insulated glass in its window lite(s).
The hardware lock mechanism is shown atop the meeting rails.
Sash
A frame for the moving portion of an operable unit and for the fixed sash within a single-hung window unit. The sash is inserted inside the window unit frame.
Below are the components of a sash:
Rail
The top and bottom horizontal pieces of a sash. The two rails that align when a single-hung or double-hung unit is closed can be called a meeting rail.
Stile
The vertical piece on each side of a sash.
The window stop is the vertical piece of wood to the left of the sash. Note the handle for lifting the lower sash.
The horizontal piece of wood at the bottom is the casing sill which sits in front of the window frame sill.
The black frame is for storm windows. There are three tracks: the innermost track is for the screen sash, the middle is for the lower glazed sash, and the outer is for the upper glazed sash.
Screen
Photo by Craig Klomparens, courtesy Tilton, Kelly + Bell.
A framed mesh of narrow interwoven wire set into a window unit or added over a window unit. The screen keeps bugs out when a window is open but allows the view out of the window to be maintained and air flow to occur.
A series of large screens can also be used as an enclosure for a porch.
Photo courtesy Tilton, Kelly + Bell.
Stop
A fixed piece of wood used as a guide for raising or lowering single-hung or double-hung operable sashes, for operable units such as casements, hoppers, or awnings to close against.
Storm Window
A thin narrow-framed window unit, typically a double-hung unit, that is not installed within a wall but instead is attached to the outside of a window to provide a weather barrier and to act as an insulation layer during cold weather.
Storm windows often have three removable sashes: a top sash with glass, a bottom sash with glass, and an inner sash containing a window screen. These units are often installed seasonally, removed during warmer weather months.
Storm windows are most commonly used in older houses with windows that don’t have insulated glass.
Unit
The individual window that is manufactured and shipped to the construction site. A unit can be attached with other units into groups, sometimes shipped together as the group.
The unit consists of the frame along with the sash, stops, muntins, glass panes, screen, and related hardware depending on the window’s function and design.
Window Types
Windows come in a wide variety of types – how the window opens (or doesn’t), and where special window units are placed.
Below is a review of the various types of windows, starting with the fixed unit and picture window, then the operable units in order by common use today, then transoms and the sidelites associated with doors, and finally the specialty windows such as glass block, the skylight, the clerestory, and motorized units:
Fixed
A fixed window is a window unit that doesn’t open. It’s typically the least common of the window types in houses, but can sometimes become a large portion of the windows when used to create a larger pattern of windows or when used in specialized groupings such as clerestory windows.
Picture Window
A large fixed window. Picture windows were common in the early ranch house designs of the post-World War II era. This window consisted of a large piece of glass framed into the wall, or two large pieces of glass separated by an inner frame of wood.
The living room had a large fixed-in-place picture window flanked by two double-hung windows to allow for air flow when opened.
Casement
The casement window is considered the oldest operable window. Historically, the window unit consisted of a frame inside of which an operable sash was attached to the frame by hinges on one vertical side of the window. A latch with a handle on the opposite vertical side allowed the the window to be pulled or pushed open and to be closed tight.
Today, casement windows are typically operated by a crank mechanism tied to top and bottom hinges, with the sash opening to the outside of the wall. An integral screen is typically applied on the inside face of the unit.
Casements allow for clean window lines for operable units. However, having to crank a window open and shut can be a bit of a pain, though some manufactures do have simpler push-out windows, typically as a pair, that you open with your hands.
Single-Hung
A single-hung window is a unit consisting of two sashes, one fixed sash at the top of the window, the other an operable sash at the bottom of the window. The bottom sash sits within full-height guide slots at the sides of the window frame. Counterweights or spring mechanisms are placed between the sash and frame to assist in raising the bottom sash.
The two sashes are offset such that the top sash is toward the outside face of the unit and the bottom sash is toward the inside of the unit so that rain doesn’t get between the two sashes. The bottom sash can be slid up to allow air into the house. When closed the bottom rail of the top sash and the top rail of the bottom sash are aligned and adjacent. Each sash is typically of the same size.
Photo by Craig Klomparens, courtesy Tilton, Kelley + Bell
Double-Hung
A double-hung window is a unit consisting of two operable sashes, one at the top of the window, the other at the bottom of the window. Each sash sits within full-height guide slots at the sides of the window frame. Counterweights or spring mechanisms are placed between the sash and frame to assist in operating the sashes.
The two sashes are offset such that the top sash is toward the outside face of the unit and the bottom sash is toward the inside of the unit so that rain doesn’t get between the two sashes. The bottom sash can be slid up to allow air into the house and the top sash can be pulled down to draw out warm air. When closed the bottom rail of the top sash and the top rail of the bottom sash are aligned and adjacent. Each sash is typically of the same size.
Most single and double-hung units today have the operable sashes such that they can be pulled inward temporarily like a hopper unit to allow for easy cleaning of the outside glass.
Tall narrow double-hung windows were common during the late 1800’s into the early 1900’s as a means of drawing out warm air in the summer. Since warm air rises, pulling down the upper sash allows the warmer air to be displaced.
Sliding
A sliding window has two sashes that move horizontally when opened or closed. It’s essentially a single-hung or double-hung unit turned on its side.
Sliding windows are the most problematic of windows because the sashes often get out-of-alignment when being pushed and pulled due to imbalanced forces caused by gravity combined with the horizontal movements. Don’t use them.
Awning
An awning window has an operable sash that is hinged at the top and opens out at the bottom.
Hopper
A hopper window has an operable sash that is hinged at the bottom and swings in at the top of the unit. Though not a common window unit, it is often utilized for light and ventilation in small areas or as a small insert into glass block to provide ventilation in bathrooms.
Bi-fold
Bi-folds are specialized windows that attach units together in such a way that they can be opened horizontally the full width of the wall opening.
Bi-fold windows combine units by hinging them together on one side of each frame, similar to bi-fold closet doors. The unit at the wall uses pivots at the top and bottom of the frame adjacent to the wall, and the end unit of the group has guides at the top and bottom of the unit that follow a u-shaped track placed at the top and bottom of the opening. This allows for easy opening by sliding the end unit toward the wall.
Bi-fold units are beneficial to use when you want to open an interior space to an exterior space without having vertical frames within the opening.
Dormer
A dormer is a window set into a roofed enclosure that projects from a sloped roof. Dormers were created as a means of using the attic space under tall sloped roofs for additional living space, typically bedrooms. Dormers can also be used decoratively, sometimes only bringing light into an attic.
Note the custom-shaped tops for the pair of dormer windows over the center of the garage.
All operable windows are single hung, with the upper divided lite sashes of each unit being fixed in place while the lower single-lite sash can slide up to open the window.
Photo by Craig Klomparens, courtesy Tilton, Kelley + Bell.
Clerestory
A clerestory is a window unit placed high on a wall or between differing roof levels.
Clerestory windows allow light to come into a room or hallway without sacrificing privacy and without giving up wall space. When placed between roof levels they can allow another source for natural light and can be placed to allow for capture of winter sunlight to heat up a vertical mass wall that can then radiate warmth in the evenings.
When an operable unit in a clerestory can be used to draw out warm air in the summer since warmer air rises.
Transom
A transom window is a unit that sits atop a door or another window unit. Often used decoratively, they’re also a way of allowing additional light into a room.
Note how the transom is operable, with hinges at the bottom and a latch at the top. It can be pulled in to allow warm air out, with the small chain limiting how far the window can open.
Sidelite
A sidelite is a narrow window adjacent to and the same height as a door , often attached together as a group. A sidelite allows light into an entry when the door has no glass, providing a means of looking out at who’s knock-knock-knocking at the door. When the door has glass, the sidelite increases the amount of lite that comes into the space.
A sidelite can be placed on one side of the door, typically on the latch side, but can also be placed on each side of a door.
Glass Block / Glass Brick
Though developed in the early 1900’s, glass block (also known as glass brick) became a decorative alternative to windows in the 1930’s. Often associated with Art Deco design and especially the Streamline Moderne style, glass block provides the benefit of light with privacy, as the block obscures what’s on the other side.
Glass block is often used in bathrooms for its privacy benefits. However, its also been used as a dynamic design element on the exterior and in the interior of houses. Its wide range of size and texture options allows for a variety of looks, and its masonry unit basis allows it to be used for curving forms and rounded corners.
Glass block is non-structural, meaning it can’t bear any structural load. Glass block does have a limited insulative property since the block consists of two formed-glass pieces joined together with an air gap between them.
Skylight
Though not typically called a window, a skylight acts as a window placed into the roof. The skylight can be fixed or operable and can be see-through or translucent using glass or formed plastic materials.
Framed skylights with glass or translucent panels, essentially windows, can be a single small or large framed unit inserted into a roof, grouped together to form a pattern of units in a roof, or be used in groups to form a shed, gable, hipped, or barrel vault roof over a room.
Framed skylights opening into a room whose ceiling is the underside of the roof are essentially windows in the roof. However, skylights are often placed above rooms with ceilings that aren’t open to the underside of the roof, requiring a shaft the size of the skylight to be built from the ceiling to the roof to allow the light to make its way into the room.
Like windows, skylights can be operable to allow in fresh air and/or to pull warm air out of the room. Such skylights are essentially hopper windows, hinged along one side then opened outward (upward) on the opposite side. The distance the unit can open is often limited to a few inches.
A newer and simpler product to bring light from the roof into a room below the attic space is the tubular skylight, known by various names including light tube and solar tube.
This unit has a small round skylight at the top that’s attached to a round metal tube with an inner reflective surface. The tube travels from the roof through the attic to the ceiling of the room. The bottom of the tube typically has a translucent panel to help distribute the light into the room.
These tubes are typically smaller than a typical skylight, with the tube sizes typically ranging from around 10 inches to 14 inches in diameter. Tube lengths can reach up to 30 feet, so using this on tall roofs or two-story homes isn’t a problem.
Cupola
A cupola has a similar purpose to a skylight, mainly letting light into the central part of a house. However, cupolas are vertical enclosures built above the roof in which windows are placed into the vertical surfaces. The light then filters down into the house via light shafts or directly when placed above a space that’s open to the underside of the roof.
Motor Operated Windows and Skylights
Windows and skylights that are out of reach can be motorized so that they can be opened and closed through a control switch easily reachable on a wall. They can also have moisture sensors that will automatically close the units when it starts to rain.
Shapes
Manufactured windows come in an array of shapes. Some manufactures can modify their shapes to a limited amount and for a hefty up-charge. Custom windows can also be made to obtain more unique shapes.
Rectangular
Rectangular windows are the standard window we see in houses. These can be square, or can be longer vertically or horizontally. These windows can be easily grouped together into pairs, triplets, or more, and can be stacked vertically to create a tall window group for rooms with high ceilings.
Manufacturers provide an amazingly wide array of size options, typically available in increments of a few inches. Be aware that there is no standard dimensions across manufacturers due to the unique construction each has. This is an important consideration when finalizing the design of your house and how the windows are integrated into the walls.
Arched
Arched windows can be an interesting addition to a home’s design. Arched windows can have a half-circle top, a shallow-arched top, or a pointed arch in the Gothic style.
A Palladian window is a group of three window units, the end units being rectangular units to each side of a tall and wider central arched unit, the arch being a half-circle.
From photo by Burnhamandroot, https://creativecommons.org/licenses/by-sa/3.0/deed.en
The name stems from the Renaissance architect Adrea Palladio, who created some of the greatest designs of that era based on the classical designs of ancient Greece and Rome.
Round / Oval
Round and oval windows are highlight windows, meaning they are placed in special locations as part of the overall house design. These are often placed towards the top of the end wall of a gable roof or within a pediment above a large porch, but can also be located in one or two locations elsewhere as part of the overall composition of the windows of the house.
A round window is often called an oculus. An oculus was originally a round opening in the roof at the top of a grand domed space in ancient Roman architecture, allowing light into the space. It wasn’t glazed in ancient times – it was literally a hole in the roof. Rainwater would fall in through the opening to the marble floors, but be carried away by floor drains.
In later centuries an oculus would be topped by a cupola. The round form allowing in light was subsequently used for a round window in a wall.
Fan
A fan unit is essentially a half circle, a shallow-arched arc, or a quarter circle window. It’s another highlight window used in special locations or as part of a larger grouping of windows.
Photo by Craig Klomparens, courtesy Tilton, Kelly + Bell.
Custom
Windows can be built into any unique shape you want – for a nice price. Though not commonly done, having custom windows can allow for a unique design for your house.
Custom windows are often used as replicated replacements of historic windows.
Groupings
Window groupings are a series of attached window units that are placed together horizontally, vertically, or both. The simplest grouping is a double window where two rectangular units are attached to each other horizontally.
Larger groupings and groupings that incorporate unique shapes can create interesting designs and act together as a larger window in a room. Groupings can have both fixed and operable units.
Common and well-known groupings include:
Bay Window
A bay window consists of one or several units that sit in front of the plane of wall, bounded at each end by units that angle back to the wall. An alternative is the insertion of such a group into a wall that also forms the bay shape.
Bay windows were originally created as a means of creating air flow in a room. Each angled unit could be opened allowing air to flow from one unit and out the next, bringing in fresh air while drawing out stale or warm air from the room.
Photo by Craig Klomparens, courtesy Tilton, Kelly + Bell.
Bow
A bow window is similar to a bay window in that it projects out from the exterior wall. However, the multiple units are each at a slight angle to its neighbor creating a horizontal arc of windows. This form can also be built into a wall that matches the curve of the bow.
Photo by Craig Klomparens, courtesy Tilton, Kelly + Bell.
Materials
There are four materials that are typically available for residential windows: Wood, metals, fiberglass, and vinyl. Newer technologies have allowed for the integration of protective coverings over the exterior face of wood units that replace the need for painting them.
Wood
Wood is the most common and historic material that’s been used for centuries. Today wood windows are typically made of Pine, but options are available for other woods such as Cedar, Cherry, Douglas Fir, Mahogany, Maple, Oak, and others.
Wood has been in continual use due to its being readily available, its ability to be easily formed and profiled, and its longevity when properly installed, finished, and maintained. The main concerns with wood have to do with potential swelling due to seasonal moisture changes, rot when not maintained, and the potential for termites.
Wood has also been popular due to its warmth, tactility, and familiarity. Stained wood allows its unique and appealing properties to be seen. Wood is comforting, feels good to the touch compared to other materials, doesn’t transfer temperature as easily as other materials, and is something we’re familiar with.
Clad Wood
Over the past few decades wood window manufactures have sought to address concerns regarding wood’s durability and maintenance. Two options came out of this: aluminum clad windows and vinyl clad windows.
Both options provide good protection of the wood, have good overall performance, and have a wide range of color options. The pro’s vs. con’s are small between the two cladding materials, so it comes down to research of the manufacturers, recommendations by builders and architects, and preference as to the look.
Metal
Metal windows have been used for centuries, starting as far back as the Medieval period. Originally created by blacksmiths, metals for windows started with the use of wrought iron. The Industrial Revolution brought above factory-produced metals of higher quality and performance, with copper and iron being the most popular for windows in that era.
Below are the common metals used in windows today:
Steel
The mid-1800’s brought about the process of hot rolling steel, which could be used for windows. The use of steel windows in houses started to advance in the post-World War I era, and rose with the popularity of the Art Deco and Streamline Moderne house styles.
Steel windows allow for very thin profiles for the frame, sash, and muntins, creating a sleek look with minimal material. This maximizes the amount of glass within a given window or window group compared with wood windows.
Recent developments in thermal breaks to reduce temperature transfer and condensation along with factory-applied coatings have made steel a newly-revived option for residential windows.
Note the open casement units that are inserted into the steel framing.
Photo by Codera23.
https://creativecommons.org/licenses/by-sa/4.0/deed.en
Aluminum
Aluminum’s use in residential windows started in the 1930’s and has since surpassed steel in its popularity. Aluminum uses extruded metal profiles for the frames, sashes, and muntins and can provide narrow site lines similar to steel. However, most aluminum windows use similar sizes and profiles as wood windows, often matching a manufacturer’s wood window style.
Aluminum is a durable material resistant to degradation. The use of thermal breaks has reduced temperature transfer through the frame, and factory -applied coatings provide a range of color options.
Due to its nature, aluminum windows aren’t recommended in seaside environments without special treatment due to corrosion from sea salts in the water and air.
Fiberglass
Though fiberglass as a material has been around since the 1930’s and the current manufacturing process since the mid-1940’s, fiberglass residential windows haven’t been available for as long a time compared to other window materials – only the past 20 years or so. Though it had some issues early on, fiberglass has since become a good cost-effective alternative to the other materials.
The main concern with fiberglass windows in the past has been UV degradation causing the exterior surface to become chalky. Factory applied finishes have improved UV protection, so that isn’t much of an issue.
Fiberglass is strong, impact resistant, thermally stable compared to aluminum and vinyl, and has lower heat transfer than aluminum. Its manufacturing process allows for thin frame and muntin profiles.
Fiberglass windows currently have a limited number of finish color options, but can be painted easily. Though it’s manufactured by a variation on extrusion, called pultrusion, it can be molded into arch shapes and curves.
Vinyl
Vinyl windows are the cheap and easy option, but you get what you pay for.
Vinyl is a plastic material. Though its inexpensive to manufacture it can turn brittle with age and exposure to cold temperatures. The frames and sashes are formed with thin and flexible walls that can lead to deformation, especially in hot weather and direct sun. This deformation can lead to water intrusion.
Vinyl is also limited in color options compared to wood cladding and aluminum window options. However, it does have good resistance to temperature transfer, comparable to wood.
Specialty Materials
Though limited to the very high end due to cost, other materials for windows that can add a unique element to a house design include bronze, stainless steel, and windows clad in bronze, copper, or chrome.
Photo by Tassilirosmar
https://creativecommons.org/licenses/by-sa/3.0/es/deed.en
Comparitive Summary of Common Window Materials
| Wood | Clad Wood Alum | Clad Wood Vinyl | Steel | Alum | Fiber-glass | Vinyl | |
| Looks | Great | Good | Good | Great | OK | OK | Meh |
| Colors | Unlimited | Good | Good | Good | Good | Limited | Limited |
| Thermal Quality | Good | Good | Good | Low | Low | Good | Good |
| Lifespan (years) | 30+ | 15 to 20 | 20 to 40 | 30+ | 15 to 20 | 20 to 40 | 20 to 40 |
| Upkeep | Moderate | Minimal | Minimal | Minimal | Minimal | Minimal | Minimal |
| Green Factor | Good | Moderate | Low | Moderate | Low | Low | Low |
| Cost | High | High | High | High | Moderate | Moderate | Low |
Appearance is subjective and will be determined by you for your project.
Lifespans can vary greatly depending on quality of the product (for any material), quality of the manufacturer, quality of installation, house settlement, climate extremes, and especially maintenance. The numbers shown are mid-range lifespans,unless noted otherwise, taken from various sources. Wood and steel windows have been in use for 80 or more years in many historic buildings.
The green factor takes into account material sourcing, energy needed to create materials, manufacturing processes, environmental impact on the occupants, and general environmental impacts. Some materials might be good in one aspect but poor in other aspects.
Cost can vary greatly within each window material depending on the manufacturer, quality of the product, warranties, the product options selected, regional costs, and other issues.
Glass
Glass for windows, made from silica – the primary component of sand, is what you see through and what helps keep out water and wind. It can be basic or decorative. It can also have a variety of performance qualities.
Glass is a major conductor of temperature from outside to inside and is therefore an important consideration.
Plate Glass
Plate glass, also called flat or sheet glass, is what’s used in most windows. Basic plate glass is annealed, meaning it was slowly cooled after being formed in order to reduce internal stresses.
Insulated Glass
As mentioned earlier, insulated glass places two pieces of plate glass and adheres them to an airtight frame within which a vacuum is created or in which dry air or an inert gas is inserted. The space between the panes of glass provides some insulation between the outside and inside temperatures.
The glass unit consists of the airtight frame sandwiched by the vertical panes of glass. Light-colored sealant is installed at the sash on each side of the glass unit.
Photo by Kozuch.
https://creativecommons.org/share-your-work/licensing-considerations/compatible-licenses
Insulated glass performance is often augmented through gases and coatings, which are reviewed below.
Gases
Argon is the most common gas used in an insulted glass unit. Krypton and Xenon can also be used but are rarer gases and therefore more expensive. These gases aren’t visible, so they don’t impact the view out the window.
Coatings
Coatings have been developed that can be applied to plate glass to improve a window’s thermal performance and to protect from glare.
The industry-standard coating is called Low-E, for low-emissivity. Emissivity is the ability to emit infrared energy. A virtually invisible coating on the surface of one glass unit, Low-E reduces the amount of infrared and ultraviolet light coming through the window with minimal impact on the amount of light that comes in.
Low-E coatings come in various options for differing performances, such as improved solar control and for regional code requirements.
Tempered Glass
Tempered glass is a heat-treated glass that strengthens its ability to withstand blunt impact. Categorized as a safety glass, which is required by codes and good practice for certain areas and uses, it should be used for glass in doors, all-glass doors, door sidelites, windows that extend down close to or at the floor, skylights, sliding doors, glass railings, and around areas such as swimming pools.
Tempered glass, when shattered, doesn’t break into larger sharp pieces, but instead into numerous small pieces similar to beads. This reduces the potential for injuries.
Laminated Glass
Laminated glass is another type of safety glass. It consists of two or more layers of glass, each layer adhered to a thin clear or translucent sheet. This sheet keeps the glass from breaking apart on impact. It can often be used in place of tempered glass, but check with your local code authority. It is also often required in skylights.
The inner sheet can also have patterns or colors or be made opaque, but these are custom elements.
Divided Lites
Divided lites are a means of creating a pattern of glass in a window. Historically, plate glass could only be made in smaller sizes, so a system of wood muntins were created as smaller frames in which glass could be inserted into the window. This is the traditional grid look you see in windows.
The use of insulated glass in residential windows has challenged the use of divided lights. The thicker insulated glass units require deeper and heftier muntins. Such a true-divided-lite window can still be made by many manufacturers but at a greater expense, though creating a better and more authentic look.
Many manufacturers have developed alternatives that replicate the look (to moderate to poor degree) while maintaining the large single insulated unit in a sash or frame. These include:
- Simulated Divided Lite: A profiled wood, metal, or vinyl grid is adhered to the outside face of the glass unit, while a profiled grid as adhered to the inside face of the glass unit. A spacing bar between the glass panes can often be included. An alternate option is to have the profiled grid only on the interior side of the window unit.
- Removable Grid: A wood grid matching the muntin pattern is inserted into the window frame or sash on the interior side of the window.
The problem with these alternatives is that the window won’t look right. Though the inside/outside adhered grid looks fine from a distance, up close it looks fake. The one-side-only grid looks fake and flat since the glass from the outside floats in front of the grid. The inside ‘snap-in’ grid is just as bad if not worse since it tends to hover in front of the glass rather than attached to it.
If you’re designing a house in a more traditional style and want the divided lite look, go for the true divided lite. Otherwise it’ll read false.
If you’re designing something other than a traditional house, don’t use the simulated or removable grids divided lites because they look cheap and fake. There are plenty of other ways to use non-divided-lite windows in groups in a pleasing, aesthetic, and dynamic way.
Specialty Glass
Specialty glass provides a means of creating something unique to you through the use of various uncommon materials and techniques. Due to their special nature, glass created from these materials won’t typically be able to be part of your typical manufactured window unit. However, it could be created to act as an actual window as long as the custom window unit is detailed appropriately and that you understand its limitations in performance.
Most glass windows that utilize these materials today are used either as inserts in front of windows on the inside of a room or as unique design elements elsewhere inside the house.
A few of these materials can sometimes be integrated into the manufacturer’s windows. Be sure to inquire with the manufacturer if you’re interested in doing that.
Below is a summary of many of these specialty glasses.
Colored Glass
Colored glass uses special materials during the manufacturing process to create glass with color. This is used decoratively, and typically not in insulated glass.
Leaded Glass
Leaded glass is a composition of small pieces of glass fit within a grid or pattern of thin lead or copper strips. This is commonly found in Tudor and Elizabethan style houses but has been used in many other house styles.
Beveled Glass
Beveled glass has an angled edge at the perimeter of the glass. This is commonly found in mirrors but has been used in leaded glass windows.
Stained Glass
Stained glass uses a combination of small color glass pieces to create a pattern or picture using the leaded glass method. This is what you typically see in older churches and cathedrals.
Photo by Stilfehler.
https://creativecommons.org/licenses/by-sa/4.0/deed.en
Pattern Glass
Pattern glass uses either acids or sandblasting at the end of the manufacturing process or decorative sheets in laminated glass to create patterns or images.
Textured glass
Textured glass is cast such that the glass surface is uneven to diffuse any light or images coming through the glass. The uneven surface can be random or be cast into distinct geometric patterns.
Glass block uses two cast pieces that are joined together to create a thick glass element that can be laid like masonry into a variety of sizes and forms.
Translucent Glass
Translucent glass is glass that lets light through the glass but diffuses any image seen from either side. Translucent glass can be textured or can be created through the use of acid etching, sandblasting, or the inner layers of laminated glass.
Opaque Glass
Opaque glass does not allow light through it. Not common in residential houses, opaque glass is either coated on one side with an opaque material such as paint or an opaque sheet that can be applied in laminated glass.
Reflective Glass
Reflective glass uses a surface coating that bounces back an image, such as a mirror, or that reflects light for improved energy performance in windows.
Smart Glass
Smart glass is a newer technology that allows the amount of light through the glass to change, the glass going from clear to opaque. A variety of techniques and applications are available. The best known is the switchable glass, where the application of electricity to the glass via a switch changes it from clear to opaque. Another application allows the opacity of the glass to vary by time of day and sun exposure.
Integral Window Coverings
Several window manufacturers have innovated on the triple-pane insulated glass by inserting blinds in the inner gap. The blinds can come in a variety of styles and colors and can be adjusted easily, being lowered, raised or adjusted to limit the amount of light coming in.
Having these coverings inside the window unit keeps them from becoming dusty, improving the air quality of the home. They also take away one of the tasks that none of us really like to do…dusting the blinds.
Window Hardware
Operable windows – those that can open and close, utilize a variety of hardware based upon the type of window being used. The visible pieces of hardware such as cranks, latches, and locks are often available in a variety of materials, finishes, and styles.
Window Sizes
Window manufacturers typically have a wide range of standard size options of each type and style of window. Each window can be available in dozens of heights and widths, typically in increments of a few inches, giving you room to play with your house design. Many manufacturers can also customize sizes of their products for an up-charge.
Be aware that each manufacturer’s window will vary in size for a similarly-sized unit due to their unique design and detailing for each window. This requires you to be aware of the differences between their size options when designing your home and allowing for adjustments in detailing and installation should you bid multiple manufacturers.
There are also manufacturers that will build custom-designed windows for your project regardless of size (within reason), style, profiles, or viable materials.
Things to Consider
Light & Ventilation
Each habitable room such as a living room or bedroom must have a window. Building codes often require minimum sizes of windows for minimum light levels for each type of habitable room. Codes also require operable units that allow in certain amounts of air.
Benefits of Windows in Other Rooms
Beyond code-required windows, keep in mind the benefit of having windows in other rooms and spaces such as laundry rooms, offices, work rooms, rec rooms, bathrooms, and even garages. Having natural light and ventilation available in those spaces will improve the quality of life in your house.
Emergency Egress
When placing living spaces and bedrooms on upper floors be aware of the need for emergency egress from each room. If you have one stair in the house and it becomes unusable you’ll need the occupants to have an alternative way to get out of the house. Many codes require operable units larger than a minimal size to allow for someone to get out of the house through the window.
Shutters
The last thing I’ll touch on is shutters. Shutters were originally a necessity at windows. At one time glass wasn’t available so shutters were used to open up the house to light and air and to close up the house at night for security.
Shutters continued to be used even once windows started be glazed. Windows would often open inward while the shutters would be closed for privacy. The shutters were often louvered to allow in air and some light while providing privacy.
The important thing to be aware of is that shutters were originally designed for the size of the window. Unfortunately, shutters today are tacked onto exterior walls as decoration, often way too small for the windows they’re next to.
The larger windows on the second floor have shutters that are ALMOST the correct width to match the window width – but a tad narrow.
The narrow band of windows above the entry has two small shutters tacked on to each end.
NEVER EVER DO ANYTHING LIKE THIS!
There is no way shutters would ever be used to cover multiple window units attached together, much less a group this wide!
Another thing of note: look at how the flimsy windows look cheap, with the divided lites looking flat because they’re placed only on the inside face of the windows.
Google Earth image.
If you wish to have shutters for your house for aesthetic reasons be sure that they are sized such that they could close up and cover the full window opening. Better yet, design them to be actual operable shutters. They’ll look better when they’re real compared to tacky tacked-on embellishment.
Note: All photos are by Cayl Hollis unless noted otherwise.
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