Window Replacement Materials and Styles
For centuries, wood was the traditional material for windows, and despite new competition, it's still a popular choice today. Aside from looking good, wood is a renewable resource, and in today's eco-friendly environment that is certainly a plus. Of course, there are other advantages. Wood windows can be painted or stained to match your interior and exterior color schemes. Wood frames can lend a rustic, homey look or an air of elegance and sophistication. They can match and accentuate your furniture and cabinetry. Wood frames are an excellent choice for older, historic homes.
A handful of regional manufacturers (such as TrimLine Windows) specialize in custom wood windows as a standard operating procedure. As high-end windows, you will pay more, but the custom sizing will be part of the order rather than an additional cost. As true "pocket replacement windows," they're designed to fit into the 3 1/4 -inch space where the old wood sashes used to be. This means you won't have to replace the interior or exterior trim, and you can get all the advantages of a wood window without the usual installation problems.
Aluminum was really the first non-wood replacement window, and they were very popular in the 1950s and the next few decades. Aluminum windows are very strong, don't have to be painted, and are highly effective at noise reduction. As a metal, however, they are good conductors, which isn't exactly a benefit. In fact, they conduct heat approximately 1,000 times faster than wood or vinyl.
Today they are most commonly used in commercial buildings, as builders are willing to trade their heat loss and gain for the strength they offer for large openings. By most estimates, you could cut your heating costs by as much as 50% by replacing your aluminum windows with energy-efficient windows.
Vinyl is one of the most popular choices for replacement windows. Economic and efficient, vinyl windows offer homeowners a wide variety of color combinations. In the past, vinyl windows were considered unpaintable, leaving homeowners locked into their color decisions, but in recent years paintable and stainable synthetic surfaces have been introduced. There are even woodgrain laminates so effective, it's often hard to distinguish between today's pre-finished woodgrain windows and actual stained wood. For those who desire the look of wood but don't have the budget for it, a vinyl window with a woodgrain laminate puts that design decision back in play.
Cellular PVC Windows
Cellular PVC (celuca) windows are one of the newer innovations in window technology. Cellular PVC is a particularly strong and flexible form of vinyl (it is about 46% stronger than regular vinyl, and the sash is 82% stronger) that looks like wood and offers all the advantages of wood (intricate detailing, etc.) without the potential of rot or termites.
It is produced through a slow, foaming extrusion process (extrusion is what happens when you squeeze toothpaste from a tube), and then it expands as it cools and hardens. During this process, 'blowing agents' create tiny air bubbles, which makes cellular PVC less dense and about the same weight as a soft wood. It can also be handled (sawn, sanded, etc.) like a wood. It has a tensile strength, however, of 2,000 to 5,000 psi, a low thermal coefficient (144% better than regular vinyl), and a temperature tolerance range of about 40F to 150F. It does become brittle under 40F, so if it is being installed during the winter, it should be pre-drilled.
Its strength makes it a good choice for large windows. It is more expensive than wood, but it is also impervious to moisture, bugs, and warping, and it is also a 214% better insulator than vinyl and a 60% better insulator than wood. It comes in standard widths and thicknesses, so any variations would probably have to be custom ordered.
Fiberglass windows are one of the newer window choices, and a viable 'green' alternative for those concerned with the offgassing involved with vinyl. Fiberglass windows are made with post-consumer recycled glass (about 60%) and are durable, long-lasting, paintable, and very strong. They won't rot, warp, shrink, sag, or become brittle.
Fiberglass is about 3 times stronger than aluminum and 9 times stronger than vinyl, and is more energy efficient because it doesn't conduct. Its rate of expansion is about the same as glass, to there's less torsion and air leakage. (Its expansion/contraction rate is about 1/3 that of aluminum, and 1/7 that of vinyl.) Fiberglass is an insulating material, so it doesn't need metal stiffeners, as vinyl often does, or a thermal break like aluminum windows.
You can easily find fiberglass windows with low U-factors and Energy Star certification. They do not corrode, rot, or warp and aren't susceptible to bugs, but they are about 10%-30% more costly than a mid-grade vinyl window.
Composite material is a mixture of substances, in this case ground-up vinyl with sawdust or wood chips, with epoxy as binding agent. Some manufacturers use recycled plastic or vinyl to make their composite windows.
Composite windows are strong, and resistant to wear-and-tear. They are thermally similar to wood, but are resistant to rot, warping, and insects, as well as heat and moisture. They are dimensionally stable and feature low rates of air leakage.
Composites are relatively new, and relatively expensive within the replacement window market. They are typically more expensive than vinyl but less expensive than clad wood. Composite windows are another option for homeowners who want the look of wood, without the expense.
As composites were introduced in the 1990s, the jury is still out on their long-term performance and benefits. It is recommended that you look for composite windows with heat-welded rather than fastened joints and color consistency throughout the frame.
In the past few years, vinyl and cellular PVC have become some of the most popular types of replacement windows, but while their cost is a big selling point, they do have their advantages and disadvantages. Take care while weighing your options, and be sure to consider factors other than cost. There are many forums on the internet where homeowners share their uncensored experiences, as well. Call some professional window companies to discuss your project and concerns and get a bid, but beware of high-pressure sales tactics.