California contractor Bill Robinson has a sure-fire way to determine whether or not a window should stay. If it isn't working, it's out.

Normally, Robinson says, windows need replacing if they're leaking, losing energy, or if the homeowner feels in need of a style switch.

But any nonfunctioning window is an open-and-shut case, so to speak.

Mike Magden, president and CEO of Regency Windows, in Twinsburg, Ohio, says reasons for replacement include “sill failure, drafts caused by air infiltration, sashes painted shut or that otherwise don't operate, sashes that are loose or rattle, water condensation, and windows that need reglazing because the putty's falling off.”

In and Out For Ken Moeslein, owner of Swingline Windows in Pittsburgh, a window nailed or painted shut raises “the egress issue.”

“I'll say, ‘What would you do if you had to leave [in an emergency]?' And they might say, ‘I'd break the glass.'” In addition, he points out, many older windows no longer have functioning locks, “so security is an issue.”

And in just about any estimating situation, single-pane glass is a reason to replace.

“The energy rating on that single-pane window might be R-1,” Magden says. “We can put in a window as high as an R-10.”

Change of View Old windows aren't the only ones that need replacing. New tract housing sometimes offers curb appeal — brick exteriors, kitchen islands — but skimps on doors and windows.

“We've replaced windows in homes that were less than five years old,” Moeslein says. “They have metal windows with two pieces of glass so close you shouldn't even be able to call them insulated.”

Regency gets similar calls, frequently to replace low-quality windows in homes less than 15 years old. “You put in an $80 window, and it's not going to last that long,” Magden observes.

Clear Need Contractors point out that homeowners “just looking for information” are often trying to convince themselves. “You can just see them get the look of recognition,” Robinson says. “They've decided to replace the windows, but they're looking for reasons to justify it.” Often customers don't quibble, Moeslein says, because “the reason they let you visit is because they already have a sense of why they might need windows.”