We all hear about how various household items being marketed – from refrigerators to windows – are “ENERGY STAR qualified.” Ever wondered what that really means? I’m currently in the market for a new refrigerator, and the only thing I’m concerned about regarding Energy Star is whether or not the appliance has the Energy Star label. It either has it or it doesn’t.

Windows and doors are very unique when it comes to Energy Star. Like other items, they do have to be tested and must meet certain performance criteria to carry the Energy Star label. However, the testing is very different than that done on other items. The tests for windows and doors take into account the entire window or door—such as the window “style” (single-hung, double-hung, sliding, picture, casement or awning), the material the frame is constructed of (vinyl, aluminum, wood, etc.), and –most importantly -- the type of glass used. Double or triple-pane. The Low-E coatings used on the glass and their effectiveness. Whether or not the window has inert gas between the glass panes – and if so – the type of gas. Even the options selected for windows and doors affect their performance – and therefore, their ability to meet Energy Star requirements for labeling.

It gets even more interesting – especially in comparison to Energy Star requirements and ratings for other products – when you realize that windows and doors can qualify for the Energy Star label in one or more zones of the country – but not in others. There are actually four climate zones, and windows can qualify in numerous combinations of one, two, three or four zones. So when purchasing windows, for example, consumers need to determine whether the windows they’re considering are Energy Star qualified for the region they live in.

Now, back to buying that refrigerator.