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Just because some vinyl windows look alike on the outside, that doesn’t mean they’re built the same.  

The technology behind vinyl windows and the materials that go into manufacturing them have come a long way over the years. Vinyl windows  were first introduced to American homebuilders and consumers in the 1960s. At a time when aluminum frame windows were king, vinyl windows had to prove their worth. That’s because plastic vinyl was deemed an inferior material suitable only for children’s toys and other inexpensive novelties.

Times Have Changed

Today, vinyl windows represent the overwhelming majority of replacement windows installed in US homes. This is due primarily to their affordable price, energy efficiency and thermal insulating qualities. But what makes one vinyl window better than another? Are they all the same?

Not by a long shot.

There are some vinyl windows that are manufactured to the highest standards of quality and performance, and there are others that were made as cheaply as possible to be sold at the lowest price. Trust us when we say you don’t want to wait until after they’re installed to find out which one you’ve got. That’s why it pays to know what to look for when determining which product is best for you.

Quality is Just Around the Corner

One way to determine a vinyl windows quality is to assess how the corners are constructed. Most modern vinyl windows are fusion welded together (Heat welded together at the corners). This does not mean the qualities are all the same. Poorly manufactured products will have smaller, less substantial welds with caulk generally being applied to mask the crease at the sill. The top (head) of the window will not be fully welded, using a snap in piece to conceal the top sash when fully closed. Such a low-tech manufacturing approach often leads to poor air infiltration ratings (drafty window), lower structural ratings (sagging at check rail) and a less attractive frame.

High-quality vinyl windows feature fusion welded corners with a fully welded head and sill. The top sash will slide into the mainframe. The bottom sash will tuck into the sill, both concealed under the weld (not concealed by a snap in piece or caulked sill). Viwinco Windows’ One-Frame Technology® utilizes an exclusive four-point fusion welding technology on every sash and frame. This creates a durable one-piece sash and frame that eliminates air infiltration and water penetration. Because of this, Viwinco Windows are guaranteed not to split, rot, warp, expand or contract.

Low-E Glass: The Clear Winner

The most energy-efficient windows utilize low-emissivity (Low-E) glazing with Argon Gas filling. This helps to retain interior heat in the winter and reflect heat generated by the sun in the summer. Low-E windows provide unsurpassed energy efficiency while retaining their affordable price tag, making them a worthwhile investment for any home. Be sure to look for Energy Star compliant glass packages when making your purchasing decisions. When looking at glass ratings the lower the U-Factor the better the glass insulates during cold winter months. The SHCG (solar heat gain coefficient) determines how the product performs against the suns heat in the summer. The lower the number, the better the performance.

Other Factors To Consider

While the glass package is important to the overall performance of the window, there are other key factors that play into energy efficiency. Most manufacturers have glass packages that meet Energy Star but what about their air infiltration or DP (structural) ratings? For that, it pays to know a few key factors:

  • The industry minimum for air infiltration is .30 with the lower the number, the more air tight the product. This is tested by how much air the product leaks at 25 MPH wind speeds.
  • The industry minimum for DP ratings is DP15. The higher the DP rating, the more structurally sound the product.
  • This information is readily available and proudly displayed on Viwinco’s website. You will find that most manufacturers, including the “Big Names” (Simonton, Jeld-Wen, Alside) all hide this information. This is because their products perform poorly in these categories. When shopping window brands, demand this information. You may be surprised to what you find.

The point is, look at the big picture. A lot more goes into the products quality and efficiency than their glass rating!

To learn more about quality vinyl window construction, please browse our Vinyl Windows product page or download our brochure describing the benefits of our One-Frame Technology®.