Vinyl Window Tips
DEAR TIM: I went shopping for vinyl windows this weekend and was quickly overwhelmed. While they all appear basically the same, there seem to be differences. For example, why are some windows certified and others not? Does it make a difference how the windows and frames are connected? Finally, all the windows appear to be white, but when samples are held side by side, some are a blue-white color. What I thought was going to be an easy purchase has turned into a nightmare. Wake me up! D.E.
DEAR D. E.: You are awake, but you have crossed over into the vinyl window dimension. The only experience I can compare it with is a trip through a house of mirrors at a county fair. You must proceed cautiously and slowly through this difficult maze.
Let's start with your certification concern. The American National Standards Institute, Inc.(ANSI) and the American Architectural Manufacturers Association(AAMA) joined together to produce voluntary specifications for vinyl window construction. These specifications are very technical and deal with issues concerning durability and safety.
The certification program is very tough. Windows must be constructed using certified components, such as high quality vinyl, glass, and weatherstripping. Windows are tested randomly and periodically for a manufacturer to maintain certification status. Make sure the windows you purchase are constructed using the most recent guidelines, ANSI/AAMA 101-93. A sticker on the window frame should contain language indicating that the windows are approved.
Construction of vinyl windows is very important. There are two basic methods: mechanical connections and fully welded construction. Both types of construction can pass the rigid testing as outlined by the ANSI/ AAMA specifications. Mechanically connected windows are assembled by using screws, brackets, and caulk at the corners of the windows and frames. Connections can loosen or fail during the trip from the factory to your home. Fully welded construction takes advantage of the chemistry of vinyl. After the sections of the frame and window are cut, the mitered corners are heated. Once assembled and cooled, the two pieces of vinyl actually become one.
Heat (from direct sunlight), however, can cause big problems with some vinyl windows. Very close to 160 degrees F, most vinyls begin to loose some of their rigidity. Stress can cause frames to sag and distort. If you live in the South or Southwest, windows that face west can take a beating in the late afternoon. It is absolutely essential that you purchase high quality vinyl if you feel your windows will be exposed to this type of sunlight.
Quality windows are often constructed using frames which have many separate chambers. The cooler chambers which are away from direct sunlight help to hold the heated portions of the vinyl in shape. Steel inserts can also be used in larger windows. However, be sure the steel is encased in an inner chamber that is then welded shut. If not, your vinyl windows may actually start to rust!
The large number of chambers also provides another benefit. When mitered for assembly, the cut edge of a frame exposes the edges of the chambers. These are the parts which are heated and welded together. The more edges you have, the stronger the weld will be. In fact, manufacturers can tell you the square inch area of welded vinyl at each corner. Purchase a window with the highest square inch area.
The color differences you noticed are real. Some vinyls used in windows will change color when exposed to sunlight. Almost all vinyls will eventually begin to yellow. However, some will yellow much quicker than others. Some, not all, manufacturers tint their vinyl blue to delay this process. There are high quality blue vinyl windows, however. If you want these for your house, be sure to look for the ANSI/AAMA label.
Quality vinyl windows contain high amounts of titanium dioxide. Windows which have high amounts of this pigmenting chemical are almost always pure white. High quality vinyl also contains an organic form of the metal tin which also helps to stop the yellowing process. If the people in the window showroom act surprised about these things, keep shopping!