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How vinyl windows are made

Published: Dec. 20, 2021

Vinyl windows have become the most popular replacement window product for a reason: they’re budget-friendly, they can last 30+ years if you chose a high-quality brand, and they’re available in an attractive range of colors and upgrades. If you’re curious about how vinyl windows are made, here’s a glimpse inside the factories.

Making vinyl replacement windows

How vinyl replacement windows are madeIt all starts from a hopper full of PVC vinyl resin pellets. Mixed with additives for color, energy efficiency, UV inhibitors and other purposes using a proprietary formula unique to each manufacturer, PVC vinyl resin pellets are pulled from the hopper, melted, pressurized and extruded through a die in the shape of the window or door frame. The hot vinyl is quickly water-cooled to harden and stabilize the shape, then cut into manageable lengths. Then, it’s inspected and loaded on pallets… sent off to be transformed into windows.

These lengths are called “profiles” in the industry.

Smaller window manufacturers commonly purchase pallets of custom vinyl that’s already been extruded into the shapes they need, but the larger window manufacturers—including Pella, Andersen, Milgard and Anlin—extrude their own vinyl.

So the vinyl is extruded, what’s next?

At DunRite, we only use custom vinyl windows that are made by our manufacturers after the order is placed with the specific measurements. The vinyl windows are made to order.

They cut the length of vinyl to the correct frame size, and join the frame at right angles by melting the edges of the vinyl and pressing it together while hot, then trimming off the melted vinyl joint for a smooth appearance.

Once complete, the finished weld is stronger than the original profile.

Similarly, the pieces of vinyl extrusion creating the exterior vinyl frame – often called the casing – are cut, milled, drilled or punched to accommodate installation screws, and welded together into the final shape.

At another station, the manufacturer cuts the glass to size, washes it, adds any tint or film products necessary for that particular product or added by the homeowner as an upgrade, then builds the double- or triple-pane insert with the trimmed sheets of glass, spacers, sashing, sealings and other necessary materials to create the glass unit.

Vinyl replacement windows
Vinyl replacement windows for a DunRite customer in Phoenix

Sandwiched into a sash—the movable or fixed frame that supports the glass, and seals the panes of glass and other components into a single unit, sandwiched together by interior and exterior vinyl frames that are also welded at the corners, much like the overall window frame).

The finished sashes are then put inside the finished casing— which may have nail or stucco fins, depending on the type of installation. All hardware is installed on the window, and a sticker added that confirms the product line and energy ratings.

As the final step before it’s packaged for shipping, the assembled window is inspected and tested for performance before assembly is considered complete.

We don’t carry this brand at DunRite, but here’s a great video by Simonton that shows how their windows are made. 

That’s it! That’s how most vinyl windows are made. The finished windows are durable enough to meet stress and anti-burglar performance requirements, and withstand the demands of weather and sun for decades.

The product is delivered and installed

Once product is delivered to DunRite at our storage location in Scottsdale, we have a careful receiving process that carefully inspects the window, measures it to ensure it’s the exact size we ordered, and checked to ensure it meets the order specifications.

If the color or size is incorrect, it’s damaged in some way or there is a noticeable defect, contact the manufacturer to have the product remade on a rush delivery. Once all product is received, inspected and approved for installation, we contact the customer to schedule a convenient installation date.

Tell-tale signs of a high quality vinyl window

One of the most important factors influencing the life of a vinyl window in Arizona starts before the vinyl is even extruded or the window’s assembled—it’s the percentage of virgin to recycled vinyl in the pellet mix. Since recycled vinyl doesn’t have the strength of new, a higher the percentage of virgin vinyl creates a stronger window.

Recycled sounds great for the environment, but it doesn’t bode well for lifespan, so if you’re shopping for replacement windows, be sure to ask the salesperson about the vinyl specifics for any windows you’re considering.

It shouldn’t have any flex or give to it.

Another sign of a well-made window are a higher number of hollow chambers running through the vinyl. It adds strength and interrupts the flow of hot or cold air through the frame, improving its energy efficiency. A window with few chambers tends to be a lower quality, weaker window that was less expensive to build. This composition of the profile is also something you can ask the salesperson about.

Do you have other questions about how vinyl windows are made, or the longevity or pros/cons of brands we carry at DunRite? Reach out to us live on Facebook, send us an email or give us a call at (602) 456-2227. We’re always happy to help.

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Please note that we install replacement windows and doors, but we don’t repair them or replace broken glass. Three-item minimum purchase, some doors excluded. Refer to our FAQ and warranties page for details.


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