Most consumers have had at least one solicitation for replacement windows come their way– either in direct mail or door-to-door sales calls – whether they were looking for them or not. The sales pitches can be really compelling with offers of low-cost installation and high-yield energy savings, as well as improved curb appeal for the home.

But how’s a homeowner to know when they really need to replace their windows, and if they have the need, how do they choose the right window and the right installer?

The biggest clues come from the windows themselves. If you have moisture leaks, drafts, rotted wood frames, fog-covered glass or high energy bills, your windows might need to be replaced. The good news is that window replacement done well can net you an 80 percent return on your investment if you sell your home, according to an Angie’s List survey of remodelers and real estate agents and national remodeling industry statistics.

“When windows are old and leaky, they let a tremendous amount of energy out of the house,” says Jamie Schaffer with Superior Replacement Window & Door, Inc. in Cutler Bay, Fla. “Some of the new energy-efficient products really do make a night and day difference in lowering energy bills.”

High-quality vinyl windows are a popular choice for many homeowners. They offer good energy efficiency, come in a variety of colors, are durable and virtually maintenance free.

“Typically, 95-percent of what we sell is the white vinyl,” says Angell Ford of Window World of Central PA, in York, Penn. “People are looking for energy efficiency with a (double-pane, low emissivity, argon gas-filled glass). They’re looking for easy cleaning and a maintenance-free window.”

For homeowners living in areas prone to hurricanes and high winds, impact-resistant aluminum windows have grown in appeal over the years. They’re not as energy efficient as vinyl, which is reflected by their lower cost. Vinyl impact windows are becoming more prevalent in the impact-resistant market, but still cost 20 to 30 percent more than impact aluminum.

“Here in South Florida, most consumers are going with aluminum impact windows,” Schaffer says. “The new impact-resistant windows are very secure. Aluminum impact products don’t have quite as high energy ratings as vinyl, but they still insulate better than what most people have existing; which is just a monolithic, one-pane glass. We’ll replace that with a laminated, impact-resistant glass, and automatically that that will be a substantially better level of insulation.”

Replacement windows range in cost from several hundred to several thousands of dollars, depending on the type of window and additional features, like awnings, glass types, styles, grid patterns and shapes.

Homeowners planning to stay a while in their homes should avoid buying low-performing windows, like low-end vinyl and single-pane windows, which won’t offer much long-term energy savings. Windows should clearly display the energy performance ratings for heat gain and loss, air and sunlight infiltration.

The minimum air infiltration standard by the American Architectural Manufacturer’s Association (AAMA) is leakage of less than .30 cubic feet per minute. The lower that number is, the better. A rating of .10 or lower is ideal for cold-weather climates. Energy Star-approved double-pane glass windows require a U-value – which measures the rate of heat loss – of .30 or lower. A design pressure rating between 35 and 45 is also ideal. The higher the DP, the more durable the frame, the more water drainage it can withstand, and the more wind pressure it can endure.

When shopping for replacement windows, get bids from at least three different reputable contractors. The salesperson should be able to bring samples of his or her products and provide you with pricing and the ratings for each window type in writing, so you can make a decision that fits within your style and budget. Don’t fall for high-pressure sales tactics in which discounts are offered in exchange for you making a quick decision. A deal today should be a deal tomorrow.

If your home was built before 1978, make certain the window installers are certified by the EPA for lead paint renovation.

Window replacement is a major investment. Take your time and compare written bids. Review samples of the companies’ work. Ask them for the location of a recent home near yours that they’ve done work on so you can see for yourself how the windows look.

“You want to look at how long the company has been in business,” Ford says. “You want to find a reputable company that’s been around for a long time with a manufacturer partnership that they’ve had for a long time.” 

Angie Hicks is the founder of Angie's List, the nation’s most trusted resource for local consumer reviews on everything from home repair to healthcare.