faq

A consumer should select a window company who sells energy efficient products, has a reputation for service and stability, and provides a warranty on the unit. We recommend that you buy from a company with a commitment to participating in the National Fenestration Rating Council (NFRC) certification and labeling process and in the ENERGY STAR® Windows program.
Many companies will also participate in the American Architectural Manufacturers Association (AAMA) and will have a permanent label on the product indicating their participation. Membership in all of these organizations is an indication that you are dealing with a manufacturer who cares about the quality of their product and the product's energy efficiency.

ENERGY STAR is an independent U.S. government program establishing a standard set of guidelines to recognize the energy efficiency of various products. ENERGY STAR guidelines are used in conjunction with a variety of building materials, including windows and patio doors. Over the past 10 years, ENERGY STAR guidelines have helped double the efficiency of windows they endorse.

Low-e glass is manufactured by depositing a microscopically thin, transparent metal or metallic oxide layer on the glass. Low-e coatings reduce radiant heat loss, and can reduce the passage of UV rays. Use of heat-resistant (or absorbing) glass began in the 1950s, as did the use of reflective (or mirror) glass.

The NFRC is an independent, third-party certification organization with industry-accepted standards for evaluating and certifying energy performance. The NFRC Certificate contains U-factor, SHGC (Solar Heat Gain Coefficient) and VT (Visible Transmittance) values. These values form the basis for the ENERGY STAR® Door and Window Program.

Refers to a window's resistance to thermal transfer or heat flow. The higher the value, the better the insulation.

A measure of the rate of non-solar heat loss or gain through a material or assembly. It is expressed in units of Btu/hr-sq ft-ºF (W/sq m-ºC). Values are normally given for NFRC/ASHRAE winter conditions of 0ºF (18º C) outdoor temperature, 70º F (21º C) indoor temperature, 15 mph wind and no solar load. The U-factor may be expressed for the glass alone or the entire window, which includes the effect of the frame and the spacer materials. The lower the U-factor, the greater a window’s resistance to heat flow and the better its insulating value.