back iconBack to all photos

The Parts of a Window: A Guide to Window Design

| April 11, 2019
the parts of a window


For the vast majority of homeowners, windows are simply a means to an end: they let natural light in, they allow for a cool breeze when opened and a defence against the elements when closed. It’s understandable that homeowners wouldn’t want to concern themselves with window specifications and terminology. That said, when it comes time to purchase replacement windows, homeowners should be armed with information that will allow them to make an informed decision about how to proceed.

The following guide outlines the different parts of a window. It’s designed to help homeowners understand how different window components come together and what features to look for during the replacement process. It will also look at the design features that set Magic apart from the competition.

Click Any of the Following Links to Browse This Content:

the parts of a window

Replacement Windows vs. New Construction Windows

Before getting into the different parts of a window, it’s helpful to understand the distinction between replacement windows and new construction windows:

Replacement Windows

Also known as insert and retrofit windows or frame replacements. These are windows specifically designed to fit into a pre-existing window opening. Replacement windows are often the highest performing products in a manufacturer’s product line and are commonly used in replacement or new build applications.

New Construction Windows

Designed for new homes, or for situations where the existing window has to be removed down to the studs in order to be replaced. That said, replacement windows can often be installed “frame-out”. Many companies commonly remove old windows down to the stud, including trim, internal insulation and external flashing in order to install replacement windows.

How to Choose the Right Replacement Window Glass

We would need more than just one blog post in order to fully explain the complexities of glass, but here are some key components and terms relating to window glass that homeowners may encounter during the process of purchasing new windows.

Window Pane/Glaze

These terms refer to the cut piece of glass that fills the window frame. If a window has one pane of glass, it is a single-glazed window; two panes, double-glazed; three panes, triple-glazed. Most domestic windows on the market are either double-glazed or triple-glazed. Many companies claim that their triple-glazed windows are more energy-efficient than double-glazed windows, but this is misleading. While our custom-made double-glazed windows pass the rigorous energy-efficiency standards of programs such as the National Fenestration Rating Council (NFRC), many other double-glazed designs do not. This leads to the need for an additional pane.

The extra pane adds another layer of low-E coating, which can darken the window and affect light transmittance. Another drawback of triple-glazed windows is that they add significantly more weight onto the window’s hardware. Considering most windows on the market utilize crank hardware, this added weight can work to reduce the lifespan and performance of a window unit.

Low-E Coated Window Glass (Low-Emissivity Window Glass)

This transparent, incredibly thin coating helps to regulate the solar heat that comes through a window, allowing spaces to cool more efficiently in warmer temperatures. It is key in determining a window’s Solar Heat Gain Coefficient (SHGC).

SHGC is an energy efficiency metric used by the National Fenestration Rating Council. It determines how much solar heat enters into a home via a window. The lower the number, the less heat enters. SHGC ranges between 0 and 1 and windows are generally between 0.25 and 0.8. 

One key thing to note: A “good” or “bad” Solar Heat Gain Coefficient rating largely depends on the climate where the home is located. For example, homes in Northern Canada exposed to long winters and minimal warm weather would want a higher SHGC to take advantage of more solar heat gain. Conversely, a lower SHGC is essential in the Southwestern United States, where homes are exposed to ample sunshine year-round. Put simply, a lower SHGC can reduce cooling costs, while higher SHGC can reduce heating costs.

the parts of a window

Window U-Factor

U-factor determines the rate at which heat escapes through a window. The lower the U-factor number is, the better the window is at mitigating heat loss. The typical range to look for is between 0.20-1.20

Gas Fills

A method designed to further improve the insulation of a window. Gas fills are an essential step in creating an insulated glass unit (an IGU). In these units, manufacturers fill the space between the glass units with krypton or argon gas. These heavier, noble gases are preferable to air because they can better impede the transfer of heat through a window.

Most IGUs on the market are separated by ¾ of an inch. Because our patented parallex® hardware can stand more pressure and external torque than these traditional crank windows, we are able to extend that space to a full inch. This means we can fill our IGUs with 25% more gas. More gas leads to more effective insulation.

Warm Edge Spacers

Another integral part of an insulated glass unit. They act as seals which insulate the edges of the unit and keep the glass panes firmly apart from each other. These spacers are essential to a window’s ability to remain energy efficient over the long term. At Magic, we take this technology further. We utilize a duralight soft edge spacer made of a 4-layer material that naturally expands and contracts with any movement of the unit. This makes seal failure virtually impossible.

Glass formulation is essential to the performance of any window. That’s why we don’t take any chances. We formulate all of our own glass units in-house to ensure high-performing, long-lasting windows. The customization of our glass also allows us to maximize a window’s performance in accordance with a home’s specific geographic region and construction.

How to Choose the Best Replacement Window Frames

The frame is the structure that both surrounds and supports the entire window unit. A frame’s components can vary depending on the type of window being installed, but there are main components that are fundamental to every frame.

The Parts of a Window Frame

  • Head: The horizontal section that forms the top of the frame.
  • Jambs: The vertical sections that form the sides of the frame.
  • Sill: The horizontal section that forms the bottom of the frame.
  • Sash: The moveable panel that holds the glass and the framework of the glass firmly locked in place.
  • Mullions: A vertical or horizontal element of the frame that forms a division between the different glass units of a window.

Frames are essential for the strength, structural integrity and aesthetic quality of any replacement window. They are traditionally made from a variety of different materials.

Vinyl Window Frames

Vinyl windows are durable, energy-efficient, and require very little maintenance. This makes them the most cost-effective windows on the market. For added performance, Magic uses a modified vinyl window frame design. Our Hybrid Fusion Frame design uses a skeleton of steel and aluminum wrapped in vinyl (U-PVC). In this way, we provide the best of both worlds: the strength and durability of steel and aluminum with the efficiency of high-performing U-PVC. Our frames adapt to weather fluctuations, keeping the home better insulated year-round. We’ve also improved on traditional frames with our ultra-slim design, which reduces the frame’s size and maximizes the glass surface to create a more contemporary look.

the parts of a window

Aluminum Window Frames

While standalone aluminum frames are durable and relatively inexpensive, they have a very high U-factor. As mentioned earlier, U-factor is a measure of thermal transmittance or the rate of heat transfer through a material. Aluminum loses heat and cold very quickly, making it the least energy-efficient frame option.

Wood Window Frames

Wood frames are sturdy, constructed from a renewable resource and have a high aesthetic value. That said, wooden window frames are very expensive, require regular maintenance (painting, sanding, caulking) and are prone to rot and mildew. They can also expand and contract in extreme weather conditions leading to insulation issues.

Composite Window Frames

Composite frames can be used in a number of different applications because they appear to be solid wood, but are in fact a combination of materials such as wood, vinyl and resins that come together during the manufacturing process.

Fibreglass Window Frames

Fibreglass frames are becoming increasingly popular in the industry. It is the newest material to be used in window frames. Fibreglass is strong, durable and requires very little maintenance. For added insulation, many manufacturers will fill the frame’s hollow core with foam.

How To Choose The Best Replacement Window Hardware

Window hardware is responsible for controlling the basic functionality of a window. Quality hardware is crucial to the long-term performance of any replacement window or new construction window.

Casement Window Cranks

Traditional casement windows open and close by means of a hand-crank mechanism. When the window is open, a friction hinge or a stay holds the sash in place. Even though cranks have been used for decades, they are mechanically flawed. They will strip, break and loosen over time, especially when they are used on heavier triple-glazed windows. That’s why we decided to do something different.

Crankless Parallex® Hardware

Our patented parallex® hardware turns outdated casement crank windows into crankless feats of engineering. Instead of operating the sash with a crank, our revolutionary parallex® hardware allows homeowners to swing the sash outward by sliding it seamlessly along a horizontal axis. This functionality also allows homeowners to “grab” air from the exterior of the home to help keep the interior cool. Our patented hardware can stand much more stress and weight than traditional crank windows and outperform these outdated designs in every way possible.

the parts of a window

Multi-Point Window Locks

This secure locking system holds the window in place in two or more places simultaneously. The locks grab the sash and push it firmly up against the frame.

Cam Locks

A cam locking mechanism consists of both a base and a cam. The cam sweeps or rotates on the base before latching onto the sash, holding it locked in place against the frame. Magic fashions both our cam and multipoint locking systems from stainless steel to ensure security and peace of mind.

Window Drainage Systems

In order to prevent the buildup of rainwater in the window unit, windows should be outfitted with drainage systems. Our patented polycarborbonate drain eliminates the buildup of water while simultaneously preventing air drafts and insect penetration.

How To Choose The Best Replacement Window Screens & Blinds

parts of a window

Screens and blinds are designed to cover the opening of a unit to shield light, heat, dust, insects and other outdoor debris from entering the home. Whereas traditional blinds are vertical or horizontal slats constructed from a variety of materials, screens are traditionally made of tightly-woven wire.

While screens and blinds are both essential components of a window, these traditional designs have a number of flaws. They collect dust, they attract dirt & mildew, they block natural light, they obstruct views and contain flawed hardware. Not to mention the bulky, outdated design. At Magic, we’ve worked to redesign these window features to make them perform more intuitively.

Retractable Insect Window Screens

Outdated insect screens block light, obstruct views and can become clogged with dirt and allergens over time. Built with our patented Retractable Slide ‘N’ Hide® technology, our fully retractable insect screens address these issues by allowing homeowners to fully control when and where they use their screens.

Built-in Solar Window Screens

These solar screens also utilize Retractable Slide ‘N’ Hide® technology. They allow for unprecedented control over how much solar light and heat enters through a window. The retractable option lets homeowners utilize or block out the sun’s heat whenever they choose to.

Built-in Thermal Blinds

Our fully-retractable thermal blind can double the insulating value of any unit. It reduces utility bills by preventing comfortable internal air from escaping the home. Furthermore, the blind’s ability to retract allows for steady natural light transmittance that would have been permanently lost with an equivalent triple-glazed unit. The blind can also completely block out light penetration, providing increased privacy and security.

Have More Questions? Book A Free Consultation

Despite all this information, homeowners will inevitably have more questions regarding replacement windows. That’s why we offer free, no hassle consultations. We understand that every home has unique needs based on its aesthetics, geography and construction. One of our certified project managers will help to explain the innovative design features that set our windows apart and how they can be customized to suit any home. Book a free consultation today and see first-hand why Magic produces the world’s most advanced replacement windows.


Learn More About Window Replacement on Our Blog: 

  1. Energy-Efficient Windows: Here is What to Look For
  2. The Benefits of Retractable Window Screens and Blinds
  3. 6 Ways to Tell if You Need to Repair or Replace Windows
  4. Why Crank Operated Casement Windows are Mechanically Flawed
  5. 4 Stunning Panoramic Window Walls
  6. The Main Issue With Hollow Vinyl Replacement Windows
  7. 3 Factors That Lead to Secure, Durable and Efficient Replacement Windows
  8. The Window Energy Rating Costs You Money: So Why Do Companies Promote It?
  9. Sliding Windows vs. Hung Windows: Understanding the Difference
  10. Is There a Best Window For Cold Weather Climates?


The project of your dreams is just a few clicks away. Book your free no obligation consultation with us:

Want free window information?

Simply enter your information below and we'll send it right to your inbox.
Give it a try, you can unsubscribe anytime.