The process of researching and shopping for windows and doors can be daunting – even maddening for the average homeowner. Not only are there many styles, materials and brands to choose from, but the industry codes and ratings can be very confusing, leaving one frustrated. Familiarizing yourself with window lingo will not only educate you, but will make the process of picking out your new windows and doors an enjoyable one. Whether you are replacing old, drafty windows and doors, planning a remodel or building a new home, the information below will help you decode industry jargon and turn you into a window and door expert in no time.
Energy Efficiency -
First things first, make sure you are selecting an energy efficient brand. The easiest ways to ensure this is to look for the ENERGY STAR label. Companies that have earned the right to use this bright blue logo, provide you with more than just an average window or door. This important label signifies that your products will use less energy, reduce your carbon footprint and best of all – save you money. Pella Windows & Doors have been named an ENERGY STAR Partner of the Year for the last five consecutive years.
Understanding the NFRC Label
Now that you know not to settle for anything less than ENERGY STAR qualified products, it’s time to discuss the importance of NFRC ratings. Each ENERGY STAR rated window or door has been individually tested by the National Fenestration Rating Council (NFRC) and bears an NFRC label on it as proof. The NFRC is a third-party, non-profit organization that grades windows and doors to help consumers compare products and brands. This black and white label is loaded with pertinent information about the performance of windows and doors. Here’s how to decipher three important NFRC stats.
U-factor -
U-factor is a term used in the construction industry to illustrate the amount of heat transferred through the structure of a building, including through windows and doors. In layman terms, the U-factor tells you how efficient windows and doors insulate. U-factors range from .25 to 1.25, with a lower number indicating better insulation. Beware of extremely low U-factors that sound too good to be true. An artificially low rating may be due to testing the center of a window pane. A reputable company will only discuss NFRC ratings, which are conducted around the seals of window and door units.
Solar Heat Gain Coefficient (SHGC)–
The SHGC measures how much heat from sunlight transmits through a window. The lower the SHGC rating, the less the window or door transmits solar heat. Typically, the SHGC rating varies between 0.25 and .80. A high SHGC may provide some bonus heat in the winter months but can also lead to high energy bills in the summer when compensated with air conditioning.
Visible Transmittance (VT) –
The VT rating explains how much light transmits through a window. This may sound similar to what the SHGC expresses, but rather than heat from sunlight, the VT measures the actual light. VT becomes a factor when thinking about how much sunlight you want in a particular space in your home. For example, a lower VT may be desirable in a home theatre. The VT ranges from .02 to .80, with a higher number indicating more light transmission.
Other Window & Door Terms
Low Emissivity (Low E) –
The term Low E refers to a microscopically thin metallic coating on a window. This process is done to primarily help lower the U-factor of a window. Low E windows and doors also offer an added benefit by protecting furniture and carpet from fading by blocking ultraviolet rays.
Insulating Gas –
Today’s windows and patio doors typically include an insulating gas between panes to aid in overall energy performance. The two gases used in window and door insulation are Argon and Krypton. The characteristics of these two gases are very similar. Both gases are nontoxic, nonreactive, clear and odorless. When a window fogs up or becomes cloudy the seal has failed and the gas has dissipated from the window.
