If you cut a vinyl window in half, you'll notice that the frame is quite different than windows made from other materials. Unlike a wood window, for example, a vinyl window is honeycombed with hollow areas for strength and energy savings. And unlike aluminum, a vinyl frame is a bit bulkier - it has more material to keep it rigid.
A thicker frame alone doesn't mean a better window. The design of a window is what determines the overall performance against sagging, rolling or twisting over time. Milgard's balanced design and precise inner wall placement result in a window with more strength. A significant part of a vinyl window's thermal performance is due to thermal convection in the frame. With Milgard's designs you can be confident they'll operate flawlessly for a lifetime - despite the climate.
Although many people think of vinyl as bending easily, its tensile strength is actually extremely good. Better than many materials, in fact. So as long as you're pulling it from end to end, it's not going anywhere. The trick is to use this tensile strength to make the window even stronger. Milgard's inner wall structure does just that - balancing strength, energy efficiency and performance.
Material Stresses
At 4,000 psi of pressure in the extrusion process, enormous stresses can remain in the solid vinyl material. These are expected and are included into the design process. At 180°, or through time, the stresses want to be "relieved."
Milgard's process and proprietary designs ensure that the stress on the interior surface always equals the stress on the exterior surface. Because if they don't, a twisted or bent shape can result.
Processing stresses can cause headaches over time:
- Deformation & Twisting
- Rolling
Rough surfaces can cause headaches over time:
- A window that gets dirtier, faster & a hotter frame surface
- Dull surface appearance