One of the first places homeowners typically look when it comes to making a change that will affect energy bills and comfort in the home is the windows. With choices such as vinyl and fiberglass windows, it’s not always clear which is the best choice. Each has its own pros and cons, largely depending on initial budget and the personal desires of the homeowner. And though the beauty of wood or the affordability of vinyl make for attractive options, it’s worth considering fiberglass as a more significant long-term improvement to a home.
Comparison chart
 | Fiberglass Windows | Vinyl Windows |
|---|---|---|
| Appearance | Smooth surface allows for painting and re-painting. Can be customized with various finishes. | Many colors available with smooth or textured stained/dyed PVC. Shape, size, and panes are customizable. However, once you pick a color, you are stuck with it; vinyl windows cannot be painted over (unlike fiberglass windows). |
| Durability | Extremely durable with excellent resistance to warping, rotting, and corrosion. Longer lifespan than vinyl windows. | Durable in most climates and conditions. Good for residential applications, less suitable for commercial buildings that need more structural strength. Vinyl windows have a difficult time handling extreme changes in temperature. |
| Insulation | Excellent insulation properties, comparable to wood but more durable. | Excellent |
| Strength | Very high strength-to-weight ratio, stronger than aluminum. Narrow frames allow for expanded views and more sunlight. | Relatively strong; however, as compared to Fiberglass, the wear and tear on Vinyl Windows happens much sooner. |
| Temperature Resistance | Excellent thermal stability; minimal expansion/contraction with temperature changes. Resists ultraviolet degradation better than vinyl. | Susceptible to temperature. During the winter, vinyl windows tend to shrink down and during the summer, they can become structurally weak. |
| Maintenance | Low maintenance; won't rot, warp or corrode. Can be repainted if desired. | Virtually maintenance-free |
| Installation | Professional installation recommended. | Professional recommended |
| Stability | Thermoset material stays stable in varying temperatures; less prone to overheating. Minimal expansion/contraction. | Thermoplastic and therefore is more prone to overheating |
| Cost | More expensive than vinyl and standard aluminum windows. Premium price point similar to high-end wood windows. | Casement: $500-$675. Sliding: $575-$775. Awning: $375. (Installation costs not included.) |
| Environmental considerations | More environmentally friendly than vinyl; uses less energy to produce than aluminum. | Some toxicity in manufacturing, but materials can be recycled. |
| Popularity | Growing in popularity for residential applications, especially in extreme climates. | Very popular in home construction, less so for commercial buildings. |
| Popular Brands | Marvin, Inline Fiberglass, Fibertec, Accurate Dorwin | American Craftsman, Andersen, Jels-Wen, Kolbe, Pella, Ply Gem, Simonton |
A Brief Look at Wood Windows
If the building in question is an antique, efforts should be made to preserve the existing wood windows. Unless they’re damaged beyond any kind of professional repair, it’s worth trying to keep them.
When it comes to having new windows installed, however, wood adds a lot of baggage and maintenance tasks. Many homeowners find this challenge difficult to address. While any window requires maintenance, wood is known for being the most demanding material to keep in good shape.
Wood is very susceptible to cracking and rotting if not maintained exactly the right way. Since the windows are of structural significance to the building, this becomes more problematic.
Issues With Vinyl Windows
Though they’ve long been the cheaper and lower-maintenance alternative to wood windows, it wouldn’t be surprising to see vinyl fading away soon. While their low cost is very attractive to homeowners, vinyl windows are very susceptible to temperature. They often shrink in cold weather and expand in hot temperatures to a greater extent than wood. Also, vinyl tends to become structurally weak at temperatures higher than 165 degrees—a temperature easily attainable in the space between a window and the drapes on a hot day.
Perhaps one of the major issues to consider when it comes to vinyl is the fact it cannot be repaired. If there are issues with the window, the entire fixture may require replacement. In this way, it’s almost more accurate to say vinyl can end up costing more in the long run.
Fiberglass: The Better Alternative
Though they may not be as common, fiberglass windows excel in the areas where wood and vinyl begin to fail. They make for an excellent, weatherproof material that can last far longer than other materials—and usually do so with less maintenance. There are several other reasons fiberglass should be considered for your home’s or commercial building’s windows.
In terms of strength and durability, fiberglass is not only much stronger than vinyl and wood, but it also will last longer due to the nature of the material—a combination of molten glass fibers and resin. Fiberglass also adapts and changes to extremes in temperature much better than vinyl or wood. The material adjusts ever so slightly and in a way that does not put the home’s structural integrity at risk. It’s also virtually impossible for temperatures to become hot enough to soften the material.
Another major advantage of fiberglass windows is their ability to be painted. While manufacturers do often provide a number of different colors and finishes for vinyl windows, they will always look the same. Fiberglass has the advantage of being more future-proof; should the homeowner decide to go with a different color scheme for the outside of the house, the smooth surface of fiberglass can be painted to match.
Though wood windows are beautiful in their appearance, and vinyl is typically cheaper, the slightly higher cost of fiberglass is well worth the investment. The material’s lifespan, durability, structural reliability and ability to be painted make it excellent for windows. Whether the need for replacing windows comes from a major home renovation or simply the desire to save on energy costs, fiberglass is—without a doubt—one of the best options available.
About the author
Paul Kazlov is a “green” home remodeling enthusiast who writes for the Global Home Improvement Blog to educate people about green products such as solar power and metal roofing. Follow him on Twitter.
Vinyl 
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Fiberglass Insulation 
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