Glass

The glass type selected is a major determinant of a window's overall performance. Because of the inherent advantages of Low E glass, it has become standard for almost all manufacturers. Options to Low e include Argon Gas, which is heavier than air, and improves the R value of the window primarily in colder climates. There are also a number of inert gas options, which are intended to provide an advantage for the manufacturer, but are more "gimmick" than substance.

Common issues

• Heat Gain/Loss: The best option currently for controlling heat gain and loss in a home is Low E glass. Designed to return heat to it's source (either the sun or your heater), Low E is a great value and should be used in all climates. Modern coating processes allow up to 87% of the visible sunlight to be transmitted through Low E, which means almost no perceptable loss of light.
  
• Fading: Caused by UV rays and other elements of light, as well as other environmental factors (humidity), fading can be controlled by Low E glass. Laminated glass will reduce UV by 99% (vs 66% for Low E) when compared to clear glass, but at almost 4 times the cost of Low E.
  
• Noise: Created by a wide variety of sources, noise can be a difficult challenge to address. Dual glaze units can be up to 50% quiter than single glaze windows, but may not address all of the noise generated outside a home. Laminated glass will improve sound insulation, but a more cost effective option is to use 1/4" thick glass to the inside of a dual glaze unit, and the manufacturer's standard exterior glass (where the Low E surface is placed). The difference in glass thickness disrupts sound waves, making the window almost as quite as one with Laminated. Also important in sound transmission is the type and quality of window. A wood or fiberglass sliding window will block more sound than an aluminum sliding window.
  
• Glare: Sunlight reflected off of other surfaces, most commonly water, is best controlled with a tinted glass. Tinted glass is not as effective as Low E at controlling heat, but is the best option when controlling glare. Grey and Brown tints are available, as are reflective glass. Reflective glass is almost transparent when the light inside the home exceeds the light outside the home, so don't expect those types to work at night or in low evening light conditions.