Humans have been installing glass windows in their dwellings since ancient Rome—hail Caesar’s architect! Windows bought these days can do a lot more than provide views: New ones are vast improvements over what was sold a few decades ago. Modern models include a lot of technology, offering better insulation, more soundproofing, easier cleaning, and a vastly improved appearance for your pad.

These and many other reasons make replacing your old windows sound like a bright idea. But new views come with a steep price tag. And while some contractors tout resulting energy savings as a reason to “invest” in their window wares, their extravagant claims and estimates are often sketchy. Plus, ratings we receive from local homeowners indicate some companies often supply their customers with substandard products and do lousy install work.

Start window shopping by visiting installers’ showrooms. Ask staffers to explain features and installation techniques, and grab catalogs to peruse later. And if you are adding or enlarging windows or doing new construction, get creative ideas online and from home design magazines.

Styles

There’s a lot to look into, particularly when adding windows or doing new construction. You’ll want windows appropriate for your house’s architecture and your neighborhood. If you live in a historic district or a neighborhood with a homeowners association, find out what is allowed. For example, preservation officials or homeowners association rules might ban vinyl windows or specify certain types of window muntins (grids). Ignore them and you might have to tear out what you install.

The most common window styles are—

  • Double- and single-hung. Double- and single-hung units look the same, but with single-hungs only the bottom sash moves. These windows can be cracked for ventilation and locked in that position, with window pins for security. Tilt-in models are easy to clean on both sides, with the marginal downside that only half the window area can be open at any time, while other styles open fully for greater ventilation.
  • Casement. These outward-swinging windows open fully for ventilation, and the view isn’t obstructed midway by the frames of two sashes. The weak link is often the cranking hardware, particularly on large units. Because casement windows also provide too-slow escape routes in the event of fire, they shouldn’t be installed in bedrooms.
  • Awning and hopper. Awning-style windows swing out at the bottom; hoppers swing in at the top. Both types of rectangular units (which look like casements turned on their sides) can be inset at the top of foundation walls to provide light and ventilation to basements.

What They’re Made Of

All styles are available in different materials, including wood, vinyl, fiberglass, and—to a lesser extent now—aluminum. The most significant differences among them aren’t materials but construction quality. A cheaply made wood frame won’t hold up as well as a top-quality vinyl or fiberglass one, and vice versa. Aluminum is no longer popular because it is a poor insulator and sometimes suffers from condensation in cold climates.

There’s a wide price range for each type of frame material, but vinyl is usually the least expensive, wood is priced mid-range, exterior-clad wood more expensive, and fiberglass models the priciest.

Other things to know:

  • Vinyl—The first generations of vinyl windows expanded and contracted too much during temperature swings. Modern models usually don’t do that, partially because manufacturers now usually stick to light colors that don’t get too hot in the sun, which limits design options. Frames with welded corners are the sturdiest and most energy efficient.
  • Wood—A traditional choice, these provide good natural insulation and can be milled to provide classic architectural detailing—even complying with historic districts and neighborhood association restrictions. Many come factory primed, ready for a finish coat in any color. Their versatility is also their main drawback: They require scraping and repainting every few years. Vinyl cladding on all exterior parts of wood windows increases the price and may limit your ability to change color schemes over time—but you won’t have to regularly repaint.
  • Fiberglass—This grainy synthetic is considered the most durable and strongest type, making it a good choice for large panes of glass and groups of several windows. It can be extruded into slimmer profiles than vinyl, making it a good choice for frame-plus-sash replacements. It can be painted and is available with wood veneer facings on the interior side.

In addition to choice of the material, you’ll need to decide on other style details, including thicker or thinner frames, more or less substantial grids (muntins), and various types of hardware.

Durability

Depending on construction, windows can last for decades—or rot and fail within a few years. Start by checking out Consumer Reports’ window ratings. It periodically tests about 15 models for resistance to wind and rain. But since Consumer Reports tested a fairly small selection of windows, you might have to do your own evaluations of durability.

Check guarantees. Better-sealed window units tend to come with warranties of 20 years or more and don’t prorate reductions in the covered value as time passes.

Consider the claims salespeople make about durability. By talking to various installers, you can get opinions on durability from companies that sell multiple brands, but this will just give you a rough idea.

Since most windows fail due to weak corner joints and moisture, ask about these hazards. To avoid moisture accumulation in wood windows, buy windows with drainage holes and spaces for air circulation.

Keep in mind that vinyl windows require no maintenance, as do the vinyl- or aluminum-clad areas of wooden ones. Exposed wood surfaces require painting, but the better manufacturers apply a thorough undercoating.