Vinyl windows are a very popular choice for replacement windows because they are inexpensive and “maintenance free”. But, before you spend your hard earned money, you may want to know some facts about the material.
The disadvantage of Vinyl framing material is that it expands and contracts with temperature changes, leaving cracks for air leakage. Air leakage in vinyl windows increased 136% — significantly more than aluminum or wood. In extreme cold this stresses the external caulk weather seal and the window literally shrinks away from the wood rough opening.
Vinyl is also very sensitive to high temperature and UV radiation, which can break down the molecular bond resulting in brittleness and discoloration. Vinyl lacks rigidity and with the expansion and contraction is subject to distortion. The average lifetime of vinyl is 15 years.
PVC (vinyl) is very difficult to repair. The material turns yellow and brittle from sunlight and forms hairline cracks. Once they have degraded, vinyl is impossible to repair. Vinyl windows have experienced problems with losing their shape as the width of the window is increased; as stress leads to sagging and distortion. The popularity of inexpensive vinyl windows has created real challenges with water penetration in the industry.
Vinyl may exacerbate water intrusion in stucco walls. Vinyl expands 7 times as much as glass causing the seal between the vinyl framework and glass to fail. The bigger the glass the sooner it fails. Vinyl also gives off gas on the interior over time releasing small amounts of vinyl chloride, a known carcinogen in humans.
Vinyl windows look chunkier because they aren’t strong enough to be made into ultra thin parts losing glass space with an unmistakable plastic look. Efforts are being made by companies to make framing materials using a combination (composites) which are more durable than conventional materials. Vinyl continues to decine as the product of choice.
When that vinyl window price looks too good to be true – it is.
Rick Brill, RbA replacement consultant