Vinyl Windows

Solid vinyl framed windows have gained in popularity in recent years since they are comparatively lightweight, have been shown to be as thermally efficient as wood, and are often the most economical option available. Typically, vinyl windows do not corrode or rust and the integral homogeneous color does not wear away, blister, crack, peel, or pit. Some manufacturers limit colors to lighter ones such as white or almond since their darker colors can promote heat buildup in hot climates that can warp or damage the vinyl. Others have developed the next generation of vinyl windows that offer darker colors along with deeper frames, more insulating air chambers, foam insulation in the frame, triple glazing, and other options. These enhancements provide greater structural performance, more design flexibility, and better energy efficiency. Some manufacturers also qualify for the AAMA Gold Label Certification Program or the WDMA Hallmark Certification Program. These programs represent air, water, and structural testing for windows and doors. AAMA also offers a silver certification which only requires thermal testing. High-quality vinyl windows are particularly well suited to situations where excellent energy efficiency and low maintenance is needed within a budget, thus offering an overall good value.

Chart courtesy of Simonton Windows & Doors

This chart shows the comparative energy loss through different window frame materials. Note that aluminum is shown without a thermal break—with a thermal break it performs much better.

Fiberglass Windows

A fairly recent addition to the window market, fiberglass framed windows consist of glass fibers and a resin that binds those fibers together. The well-known tensile strength of fiberglass gives these windows high levels of durability and impact resistance. They are better suited than vinyl to handle a wide range of temperature extremes from -40 degrees F up to 200 degrees F. The frames tend to be very energy efficient and in some cases additional insulation can be added inside the frames. Durable finishes are available with good chalk resistance and fade performance and are suitable for use in harsh environments. Fiberglass framed windows are mostly used in multifamily buildings where price, durability, and low maintenance are important and where higher-performance aluminum windows may be too expensive.

Aluminum Windows

Aluminum has been a popular choice of window manufacturers for quite a while due to its light weight and excellent strength. It can readily be formed into complex extruded sections that are strong and can efficiently achieve desirable weathering and operating characteristics. These aluminum extrusions easily provide tracks, drips, baffles, and grooves for weather stripping. These pieces can then be cut and fabricated into window units of many different shapes and sizes. Further, the appearance of aluminum can be varied by selecting from a wide range of commonly available anodized and painted finishes. When complete, the final product can be decorative, strong enough to be used in large openings, and provide a low-maintenance solution.

Aluminum does have a higher coefficient of expansion compared to other materials so that needs to be allowed for in the detailing. Its high rate of conductivity also makes it prone to thermal bridging and unwanted heat transfer. However, the current focus on energy efficiency has prompted manufacturers to increase the energy enhancement of aluminum frames through enhanced thermal breaks and other measures to limit or reduce thermal bridging. Multifamily buildings that require added resistance to wind and rain, strength, durability, and design flexibility are the most suitable application for aluminum windows. They are also popular where low maintenance is desired in moderate environments and in buildings where function and performance are important. Aluminum storefront, curtain wall, and entrance systems may also be appropriate to consider.

Photo courtesy of Space Plus, a division of The Sliding Door Company

Loft-style apartments can benefit from the flexibility and versatility of movable interior partitions that allow privacy when needed and openness when desired.