Admitting natural light, permitting views to the yard and beyond, allowing natural ventilation: windows perform a number of critical roles in a home. And because of the wide range of jobsthey must do–sometimes simultaneously–windows must be chosen thoughtfully and maintained with care.

Their work is often complex. For example, windows are expected to allow light and views but keep out wind, rain, glare, cold, and intruders. To accomplish this range of tasks, windows must be designed with a range of features that work together seamlessly.

Of course, windows come in many shapes and sizes and made of several different materials, from wood to aluminum to vinyl. Basically, all windows have frames and glass, and most have weatherstripping. Windows used for ventilation have a means of opening and closing, and may have screens to keep insects and debris outside.

When you’re in the market for new windows, knowing what features to seek can be a challenge. The buying guide information listed below will help. In this section, you’ll also find step-by-step DIY information to help with installing, caring for, and repairing windows.