1-800-377-8886
Questions? Call 1-800-377-8886

uPVC (vinyl) vs. fiberglass

uPVC insulates better.

Vinyl windows do a better job insulating your home than pultruded fiberglass windows. Unlike the pink fiberglass bats you see in your attic, which trap heat in small pockets, the frames used to make fiberglass windows are made out of compacted fiberglass which cannot trap air, reducing the frame’s effectiveness as an insulator. In fact, studies have shown that fiberglass transfers 3–4 times as much cold as the vinyl material used in our windows.

Fiberglass joints are weak.

If corner joints are created mechanically (using glue and screws), they’ll eventually fail. Fiberglass joints have to be mechanical because the material can’t be welded. As a result, service issues with fiberglass windows are both more frequent and more severe than with vinyl windows. See for yourself—check out the number of service issues listed by the Better Business Bureau for any established fiberglass window company.

uPVC Fiberglass
Lower U-factor
Strong, fusion-welded joints
Weak, screwed and glued joints
May chip, crack
Requires paint
Maintenance free
Approved for high rise applications
Figure 1 A direct comparison of WeatherGard uPVC (vinyl) to fiberglass as a material for manufacturing windows.

It’s actually not difficult to break a fiberglass corner joint with bare hands. So, imagine what happens when Michigan’s seasonal weather extremes cause structural shift in a home, placing the windows under severe strain. We encourage you to come to our factory and see how we fusion weld our windows (and you’re welcome stand on a corner joint, if you like).

Fiberglass can chip and crack.

Fiberglass is brittle and can crack and chip relatively easily. WeatherGard windows are guaranteed against chipping and cracking for life.

Never paint a window again.

The materials used to make the fiberglass resins that make up a fiberglass window are not stable when exposed to the sun᾿s ultraviolet rays, which means that all fiberglass windows (even white ones) require maintenance and painting every few years. Since fiberglass windows are painted, the finish is not resilient and very prone to scratching during assembly, shipping and installation. Because they have to be painted, fiberglass windows are not nearly as maintenance free as WeatherGard’s commercial grade vinyl windows.

Approved for High Rise Applications

WeatherGard’s commercial grade windows are so strong that we have even installed them on high rise apartments, such as the Alden apartments and the Park apartments (see 2), in which we've installed thousands of the very same replacement windows that we’re offering you. If our windows can withstand the wind and structural forces present in a 16-story building, you can bet it’ll be strong enough to last decades in your home.

Our replacement windows have been used in a number of large buildings where the forces dwarf those in single family homes.
Figure 2  On the left, the Park apartment building (a 16-story WeatherGard project) located in downtown Detroit; on the right, a scale depiction of a large single-family home.
  • © 2016 WeatherGard