Energy Star doors are rated for a few different qualities. This rating system helps homeowners compare the quality of different products when shopping for new exterior doors. These ratings will also let you know whether or not your door can qualify as an Energy Star door. Read on to learn more about the ratings for Energy Star doors.
The Ratings for Energy Star Doors
There are several requirements that Energy Star doors must first meet. First, the door must be manufactured by an official Energy Star doors partner. Second, your doors must be tested and certified by the National Fenestration Rating Council (NFRC). Finally, your doors' ratings must meet the U.S. Department of Energy's Energy Star doors guidelines.
According to the Energy Star website, "performance criteria for doors are based on the amount of glass they have (called glazing level) and ratings certified by the National Fenestration Rating Council (NFRC). Here are the NFRC's ratings:
1. A door's U-factor measures the rate of heat transfer—usually between 0.25 to 1.25. The lower the U-factor, the better your door insulates.
2. A door's SHGC (solar heat gain coefficient) is used to measure how well the door is able to prevent solar heat gain—generally ranging from 0.25 to 0.80 on a scale of 0 to 1.
3. A door's glazing level refers to how much glass your door has in its design. An opaque door has no glass. A door greater than or equal to half-lite is made of half glass or less. A door that is greater than half-lite is mostly glass, such as sliding glass or french doors.
Additionally, homeowners should be aware of their door's R-value (thermal resistance), which indicates how well your door keeps heat from escaping your home. This value ranges between R-5 and R-6, depending on the materials used. Unlike the U-factor and SHGC values, however, the higher the R-values for your door, the better insulating it is and the more likely it is to qualify as an Energy Star door.
For more information on these ratings, check out Energy Star's website on Energy Star doors.
The Structure of Energy Star Doors
There are several materials and added features that can make your door an Energy Star door. In double or triple-paned window glass, the spaces between the panes are filled with either air or gases that can boost the glass's and consequently the door's insulation. Similarly, newer door materials like fiberglass, wood cladding, or steel with polyurethane foam core are also available. These energy efficient materials provide extra insulation and have a tighter fit; fiberglass or steel will not shrink and swell due to changes in temperature. Other features like high-grade weatherstripping or magnetic frame strips can improve your door's seal as well.
The Value of Investing in Energy Star Doors
Investing in new Energy Star doors can help to reduce monthly energy bills as well as carbon footprints by an average of 12 percent nationwide. Additionally, homeowners may claim a tax credit for 10% of the original cost of Energy Star doors, up to $500, that are installed between 2012–2014.