Our second installment of window tips in partnership with the experts at Fine Homebuilding tackles the list of popular window materials, and the pros and cons of using them in your next project.
Planning a new build, remodel or a window replacement project can be overwhelming—especially when there are many variations of window and door materials to choose from and a lot of information to sift through in order to identify the material that best suits your needs.
While windows come in a variety of shapes and sizes to meet any design solution, it’s important to be aware of each type’s inherent performance attributes when selecting windows and doors for a home, especially when low-energy consumption is a goal. The most popular frame materials for windows and doors are vinyl, rolled or extruded aluminum, fiberglass, wood and wood clad with a more weather-resistant material on the exterior—either rolled or extruded aluminum, fiberglass or vinyl. Each material has its pluses and minuses.
All-aluminum or clad, and extruded or roll-formed?
Aluminum can either be extruded or roll-formed, and the difference in strength can be compared to an industrial chair versus an inexpensive lawn chair.
Extruded aluminum is preferred for cladding because of its strength and weather resistance. Clad windows shouldn’t be confused with windows that have all-aluminum frames, which are typically less energy efficient than the alternatives.
What you should know about vinyl
The white elephant in the room is vinyl, which accounts for roughly two-thirds of all of the windows installed in the United States. It’s even less expensive than aluminum, yet offers much better insulating values. That said, there are some good reasons to bypass vinyl—and to some extent even vinyl-wood composites—even if you are looking for long-term value.
Vinyl (and some composites) has poor strength, meaning it’s prone to damage during installation and to warping over time. And its insulating capability is only moderate compared to wood and fiberglass, even when its extruded chambers are filled with foam. Vinyl is prone to UV damage, making it a poor choice in the sunniest states. The vulnerability to heat and UV light is why vinyl windows are manufactured mostly in white and almond tones. Vinyl doesn’t take paint well, so you’ll be stuck with those white windows.
Vinyl also expands and contracts at a rate seven times greater than glass, which means that seasonal temperature swings can break the insulating seals around the panes, letting in air and moisture. It also has poor resistance to wear and tear, as well as the worst impact resistance of any frame material. Despite that, today’s vinyl windows are a vast improvement over the leaky, single pane wood windows of yester-year.
All-wood windows: beauty and strength with a little bit of maintenance
Next up the price chain are all-wood windows. Wood is strong and a good insulator, and it adds beauty inside and outside the home. It’s important to keep in mind that all-wood windows do require regular maintenance, which adds to their cost. If you neglect that cleaning and painting at any point, sun and rain can do permanent damage. This is why so many manufacturers offer a wood window clad with vinyl, aluminum or fiberglass.
Fiberglass is unique
As a window frame material, fiberglass offers an unmatched combination of energy efficiency, durability and long-term value. Marvin Ultrex® fiberglass, for example, is eight times stronger than vinyl and is coated with a thick acrylic finish so durable that it can be offered in dark colors without fear of UV degradation or fading.
With its very low conductivity, fiberglass is also the best insulator among window frame materials. It shrinks and expands at the same rate as glass, making its air seals as durable as the rest of the unit. Its long term stability also ensures that fiberglass windows will operate like new for decades to come.
Fiberglass windows can be priced higher than vinyl, and a bit more than all-wood, but the payback in energy efficiency, durability and convenience makes it a strong contender for best value in the industry.
For Dave Veldhuizen, who builds low- and zero-energy homes in Eugene, Ore., it’s hard to beat the practicality of U.S.-made fiberglass windows. “Windows from the Marvin Essential Collection cost less than half as much as [superinsulated] European windows, and they don’t require a six-month lead time when ordering.” In fact, Marvin guarantees delivery to the local distributor within 10 days, including special sizes.
There are two options for fiberglass windows: all fiberglass and fiberglass-clad wood. Full fiberglass models offer the best value of the two, while the clad models offer the timeless look of real wood on the interior of the home. Clad models also tend to offer the more high-end glazing options—like triple pane glass—while all fiberglass has glazing options for every climate as well. Clad windows are the most expensive category, but they offer an unmatched combination of interior wood, energy efficiency and low maintenance.
Durability and longevity
Aluminum and fiberglass are both super durable outdoors, and each has its slight advantages. Aluminum offers more options, while fiberglass has the edge in overall strength and value. Both offer a wide range of near-weatherproof color coatings, which are bonded to the cladding during its manufacture.
Vinyl cladding is less expensive than the other two but has the performance and durability problems associated with all-vinyl and some vinyl-wood composite windows mentioned earlier. To be sure your clad windows are top-quality, check to see that there is no wood exposed to the outdoors and check the specs to compare coatings between various brands. Look for a third-party rating.
This content originally appeared in Fine Homebuilding magazine.