So you’ve decided to replace your rotted, leaky windows. That’s good, since new windows provide returns through energy cost savings and even greater returns in an increased home value.

With the range of replacement window options available, however, you’re in for a lot of decision making. Do you want to replace the whole window? What about the interior or exterior trim? Do you need to replace only the sash – the glass and its casing – or the entire frame? Are you doing the work yourself or will you hire a contractor? And, do you want to buy the windows from the same place that will install them?

“With the replacement window models available today,” said Jeff Kibler, a manager for Peachtree Doors & Windows, “homeowners can replace as little or as much as they’d like – from just the glass or sash to the entire window and exterior trim. The various options can take the project from a relatively easy do-it-yourself task to a full-scale, contractor-level project.”

Measuring correctly for replacement windows is one of the most critical parts of the project. Very few homes have off-the-shelf-size windows and instead require windows sized to match existing openings.

A measurement off by only an inch could mean the replacement part may not fit the window frame. In the case of a full replacement window, an inaccurate measurement may result in the need to cut into interior sheetrock and exterior siding in order to accommodate the window. Always double check your measurements or have another person verify your results.

Double hung windows are the easiest windows to update. With a sash replacement kit, homeowners can replace just the operable part of the window by inserting a new sash into an existing window frame and jamb.

In about an hour per window, you can have new double-hung windows that operate effortlessly, stay open without ugly props and tilt in for easy cleaning. Many sash kits include features of today’s new construction windows such as smooth operating balance systems, high performance glass and decorative grilles.

You also have many choices in the material for your new sash – all vinyl, vinyl exterior with a wood interior, primed wood or aluminum-clad wood.

If you have casement (crank-out) windows or rotten jambs in your double-hung windows, pocket replacement windows can update the look and performance of your windows. These windows fit into the existing window frame, leaving interior and exterior trim intact. Do-it-yourselfers can find pocket windows in a variety of materials in tilt-in single and double hung, casement and awning, sliding and picture styles.

There are advantages to replacing an entire window. Perhaps you prefer casement windows and your home has all double-hung units. Maybe the frames on your windows have serious rot. Or, you want to replace your wood windows with a lower maintenance alternative like vinyl or aluminum clad wood.

These situations call for a more complete replacement choice, which means most homeowners will need a professional contractor or window installation firm to help complete the project.

The replacement window option you choose will depend on the extent to which your current windows are damaged or rotted. Sash replacement kits or pocket windows are sufficient in some cases; others require a more complete replacement window. The decisions are many, but the returns are considerable.