The K.C. Company Blog

Breaking the Code on Windows & Doors

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 way 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.

1. 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, nonprofit 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.

2. 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’s 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, that 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 (argon) between panes to aid in overall energy performance. Argon is 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.

ENERGY STAR

http://www.energystar.gov/index.cfm?c=windows_doors.pr_ind_tested
Department of Energy http://resourcecenter.pnl.gov/cocoon/morf/ResourceCenter/article//93
Efficient Windows Collaborative http://www.efficientwindows.org

Open the Window to Safety

No matter where you live or what you do, whether you own or rent your home, live in a townhouse, apartment or stand-alone home in the city or the country, or even if you’re visiting the home of another person, we all play a vital role in promoting window safety. Window safety starts with learning the actions you can take to observe window safety and encouraging others to do so. Responsible adults are the key to window safety. There’s no substitute for adult supervision when it comes to keeping children safe.
For more information, visit www.nsc.org.