What You Need to Know About Windows and Window Types

While they might look the same at first glance, not all windows are created equal -- Each window has a specific set of traits and will match a particular room and situation. It's simply a matter of knowing what's available and choosing the one that will provide your home or business with the functions and features that work best for you.

Window 101

Windows consist of two basic components: a sash (the part of the window that holds the glass), and a frame (the piece that the sash fits into). And how the sash moves (or doesn't move) inside the frame determines the type of window it is.

Single and Double-Hung Windows

Single and double-hung windows consist of two sections of glass, one above the other. In a single-hung window, the upper sash is fixed, while the lower sash slides. In a double-hung window, both the upper and lower sections will slide, but you can also have more than one in a window.

This can get a bit confusing when ordering, but you'll find it's generally easiest to refer to a double-hung window by the number of panes (called lites) in the sash.

Sliding Windows

Often called by other names such as gliders, sliding windows are similar to single and double-hung windows, but there are a few notable differences. First, they slide horizontally, rather than vertically, so it makes them easily recognizable.

Sliding windows will have two panes that move on a pair of tracks, instead of just one. So, if you're inside your home, you'll notice the right-hand sash moves on the inside track, while the left-hand side is toward the outside. This makes it possible for them to slide past each other easily without interfering.

This style of window offers home and business owners a number of benefits. First, because they can only be locked on the right side, they're great for spaces where the left-hand side of a window isn't easily accessible. Or looking for a window you can lock and unlock quickly.

They're also great for areas where you don't have the space for a window to swing open, such as above a deck or outdoor living space. And when it's time to clean, the panes can be tipped and lifted out, so you never have to play with ladders and extensions for your squeegee.

Casement Windows

When windows are too difficult to slide up or across (like above a kitchen counter or high on a wall, for example), consider casement windows. They have two hinges on one side of the window, with small levers to lock it on the opposite side, so they open to one side or the other.

To operate the window, you turn a small crank at the bottom of the frame, tipping the sash, pivoting it open, and swinging it past the wall. Because of this, casement windows have a number of unique advantages.

Because you can reach both sides of the glass from indoors, they're easier to clean than a fixed, single-hung, double-hung or sliding window. But, because they can open up in either direction, you need to consider the environment you live in.

You see, when the wind blows, it actually increases the window's resistance to air infiltration because it forces the sash against the frame. So, you can take advantage of this by ordering windows in the direction that works with the wind, rather than opening against it. Just be aware that you'll need space for the window to open into.

Awning Windows

These are very similar to casement windows, except they swing open on hinges at the top of the frame, rather than on either side. And while they are often installed on their own, they can also be installed under a larger, fixed window to give the room some ventilation. Just remember that, because they swing from the top, they require more space to swing outward than a casement window.

People choose awning windows for a number of reasons. First, many people like that they can deflect light rain, rather than letting it rain straight in your home. But, where you install them can make a difference, too.

When installed high on a wall, awning windows can give you some air and light, as well as some privacy. When you install them low on a wall, however, they can deflect the wind and keep the big gusts out of your home.

Fixed Windows

Just because fixed windows can't open, doesn't mean they lack in advantages. Fixed windows have a ton of advantages, perhaps the biggest of which is flexibility.

Because they don't have to worry about functionality, manufacturers can make fixed windows in an unlimited number of sizes, styles, and shapes. For example, in addition to rectilinear fixed windows, companies can also offer half-round, elliptical, and trapezoidal windows (which are often installed to match the slope of a roof) in a number of standard sizes.

Manufacturers spend a large amount of their time and money on weather stripping for moveable sashes in an attempt to make them as air and water tight as possible. But because fixed windows don't move, manufacturers don't have to worry about it.

This often makes fixed windows less expensive than functional windows of the same size, and a great money-saving alternative for rooms where you want light or a great view, but not necessarily the ventilation.

Window Materials

While it might seem like windows have very little material in them aside from the glass, the material in the frame can have a huge impact on the durability and energy-efficiency of the window, as well as their appearance.

Wood Windows

Wood-framed windows have been around the longest. In fact, they were the most popular window material by the 18th century. Their classic look still makes up approximately 50% of the residential window market today.

Part of the reason for its rise in popularity was because wood was relatively inexpensive and plentiful. Until recently, anyway. Wood is a poor conductor of heat, so wood windows are naturally higher on the scale of energy-efficiency. But it isn't all good.

Today's wood windows are treated with a special preservative prior to assembly to help them withstand the elements. Some manufacturers will even paint the exterior of your windows in the factory and offer a good guarantee. But even then, wood windows won't last forever.

If you want to keep wood windows looking their best, and keep them protected, you'd better be prepared to use some elbow grease -- wood windows will need to be scraped, puttied, and painted every couple of years.

Clad Wood Windows

Having to refinish wood windows every couple of years can easily be enough stress and hassle to trigger a divorce season. After all, that's a lot of work, time, and money you'll have to invest just to maintain the "natural warmth and beauty" of your home's windows. There is an alternative, however.

Clad windows give you the benefit of wood, but the exterior of the window is covered with vinyl or aluminum to keep it protected from the elements. They're also widely available, from a number of manufacturers. However, they can be made using a number of different methods, so you'll want to pay attention.

Some manufacturers will simply glue the vinyl or aluminum directly onto the wood, while others design the cladding to snap on like a cover. Another method involves creating a vinyl or aluminum frame and attaching a wood frame to the interior side of it.

And if you're worried about the aluminum or vinyl affecting the energy efficiency of the wood, don't. In fact, the wood interrupts the conductivity of the aluminum, so you get the best of both worlds.

Vinyl Windows

Vinyl windows are certainly not popular for their traditional good looks. Many people think vinyl is better suited to a trailer than a house, but they're definitely something you should take a second look at. And many homeowners have.

Vinyl windows are quickly closing in on wood windows to become one of the most popular window choices. And the market for solid vinyl windows is growing rapidly.

Why? Vinyl windows cost considerably less than wood and they never need painting. They last a lot longer than they used to, too. You see, early vinyl windows were terrible. The vinyl expanded and contracted at different rate than the glass. And with repeated thermal cycling, the vinyl would quickly distort and pull away from the seals around the glazing.

This would greatly decrease the window's energy efficiency and cause it to lose its watertight seal. And because dark coloured vinyl absorbs more heat than the lighter colours, it was the darker windows that generally had the most problem. One way of combatting this was to made dark vinyl windows by adhering the dark coating to a light coloured vinyl core.

Another issue with old vinyl windows was durability. Vinyl is actually an extremely brittle material made of 80% salt. When manufacturers are ready to mould it, they have to add a special plasticizer to the vinyl.

Unfortunately, the plasticizer evaporates over time making the vinyl brittle again. The solution, however, is a new vinyl formula call uPVCs (unplasticized polyvinyl chlorides), which is much better at resisting distortion, evaporation, and movement.

When buying vinyl windows, you should always look for windows with mitred corners that have been melted and pressed together so they seal, rather than simply cut and screwed together.

Aluminum Windows

In recent years, homeowners have ran from aluminum windows because aluminum is an excellent conductor of heat, and therefore, not as energy-efficient as other alternatives out there. However, they're still popular in temperate climates like those on the West Coast. And for good reason.

Aluminum windows generally cost less than wood or vinyl windows, and they require little to no maintenance. They're also stronger than vinyl or wood windows, so you can enjoy more glass and see less frame and fewer mullions.

Fiberglass Windows

Fiberglass is not a new material by any means, and it's not just for boats and surfboards. Thanks to recent advancements in technology and the development of a process called pultrusion, fiberglass windows have a number of significant advantages. (Pultrusion is the process in which glass fibers are pulled through a resign bath and into heated dies that cure the fiberglass.)

Because fiberglass expands and contracts at the same rate as window glass, the seal between the glass and sash can stay tight despite enduring severe temperature fluctuations. They're also corrosion-resistant and have superior dimensional stability, so even if you install the window on the south side of your home, it won't warp or twist.

Windows made from fiberglass don't need much in terms of maintenance and they can be painted to match your home. The only thing you'll need to be aware of before choosing this type of window material is its limits. Because fiberglass windows use pultrusion technology, they can only come in straight frames, so you would need to choose a different window material for anything requiring a curve or bend.

A Word About Window Placement

If you've ever seen a window catalogue and seen the huge walls of windows you frequently find in them, you know how stunning a wall of glass can be. The unobstructed views, the feeling of having more space, the natural light and fresh air can transform a room into an amazing space. But, don't get too carried away.

Walls that are more glass than drywall can be pretty, but they simply don't have the strength of a studded wall and won't necessarily be able to hold the weight of your home. Then, there are wind loads to consider.

Of course, this doesn't mean you can't group windows together (referred to as ganging). It just means you may need to consult an engineer before moving ahead with your plans, or you could find yourself on the wrong side of your friendly-neighbourhood building inspector.

Windows can add so much to your home, but you really need to make sure you put time and effort into choosing the ones that suit your home and your lifestyle. You'll be so glad you did.