Vinyl vs Fiberglass Windows

Monday, April 23, 2018

Vinyl or fiberglass? When you’re replacing your windows, it’s only natural that you’d want to compare different materials to get the best durability and energy efficiency for the best price. At Lifetime Windows and Siding, we’re able to provide you with a wide selection of windows, but we also want you to know the pros and cons of each one. Here’s everything you need to know about vinyl vs fiberglass windows, to help you make an educated decision.


When it comes to the strength and longevity of your windows, you don’t want to cut any corners. How frustrating would it be to have to replace them again after just a few years? While both materials are decent, fiberglass tends to last a lot longer. Since they are made of resins and glass fibers, they can hold up better against pressure, weather, and temperature changes without sustaining damage. A good quality fiberglass window can be expected to last at least 50 years, while vinyl windows may last up to 30 years.
Winner: Fiberglass


Since the most important function of your windows is to keep the outdoors where it belongs, weather-proofing is another area that shouldn’t be skimped on. Your windows need to have a tight, leak-proof seal, reduce heat loss, and minimize condensation. Vinyl is easily affected by temperature – if it reaches 165 degrees, which is easy in the glare of the summer sun, it can expand, warp, and even stink. In the winter, it can contract, possibly causing cracks and seams to appear. Fiberglass windows aren’t affected by the weather on this level and will remain the same whether winter or summer.
Winner: Fiberglass


From a distance, vinyl and fiberglass windows may appear visually similar. But if a polished appearance in your home is important to you, you may want to look a little closer. Depending on the style of your windows, they will obviously be mostly glass panes, but the frames are a giveaway to the quality of material. Vinyl windows will show all of their joint lines – which can become more pronounced after a couple hot and cold seasons – while fiberglass has a more seamless looking appearance. Additionally, fiberglass window construction has come such a long way that they can be made to mimic the traditional elegance of wood. This is a must if you take pride in the little details!
Winner: Fiberglass

Installation Time

If your windows need to be replaced, you probably want the job to be done yesterday. Vinyl is pretty widely available while fiberglass may take a little time to arrive in stock. When it comes to the actual installation process, the materials behave a bit differently. Vinyl is flexible, and can fluctuate in size within 1/8” of the window frame and still be usable, so they can be installed quickly and easily. Fiberglass is more rigid, so it’s a little more delicate of a process to correctly fit and install them in the window opening. You definitely don’t want to try to DIY a fiberglass window unit.
Winner: Vinyl

Energy Efficiency

Did you know that a quality set of windows can shrink your utility bills? They can reduce the amount of heat transmitted in and out of your home, reducing heating and cooling costs. Windows can be upgraded with energy efficient coatings or even be made extra-insulated in the materials themselves. Fiberglass windows are made of the same materials as insulation, and the fibers don’t transmit heat and cold. If you have good glass panels with energy efficient coating, it’s really the frame you need to worry about. Both vinyl and fiberglass have insulating properties, but fiberglass comes out ahead when it comes to window frames.
Winner: A Tie


When comparing the costs of vinyl vs fiberglass windows, it’s clear that upfront vinyl is the more cost effective option. However, with a shorter lifespan than fiberglass, you need to take into consideration that you would need to replace them sooner, incurring more cost. Fiberglass windows last on average 50 years, whereas vinyl only lasts about 30. If you are looking at a quick fix, vinyl is the way to go, but for a more long-term investment, it makes sense to go with fiberglass.
Winner: Tie

Window shopping can be overwhelming thanks to all the options out there, but these insider tips can at least help you choose between fiberglass and vinyl for your home. Lifetime Windows and Siding in Colorado is here to help walk you through your choices and come up with a plan of action that’s perfect for you and your home.