Eyes are said to be the windows to the soul. But where does that leave windows? As eyes to your house?

No doubt the panes of glass you choose to install in your abode can be seen as an extension of your view on life but, generally, windows are considered to be more practical--simply spaces in a wall to see out and let light in.

You want the most affordable and attractive windows to dress up your home. A contractor or glass shop may bombard you with questions and options: Double-paned? Bay? Tinted? Locking? Vinyl or wood?

"Windows are easy to install now due to new technology. Many people are surprised. Your house goes through a metamorphosis in a day," says Anthony Caronia, the manager at Thomas French Glass in New Monterey. "It completely changes the aesthetics on the exterior of the home, and adds to the beauty.

Window technology has advanced quickly in past years. Maintenance and energy efficiency have continued to be primary concerns to customers, so windows have been updated to accommodate. What''s most popular in Monterey County?

"Vinyl, definitely," says Leslie Putnam, of ABC Glass on Del Monte Avenue. "Most people take out their old aluminum, single pane windows and replace with vinyl framed, double panes. They''re virtually maintenance free, don''t corrode, don''t need paint. Most customers are split between functionality and beauty but most windows now combine both."

"There''s several styles--wood, vinyl, fiberglass--these are framing materials," explains Caronia. "Vinyl doesn''t conduct cold, neither does fiberglass or wood. The old aluminum frames did and it makes a big difference in heat or energy loss, about 10-12 percent. Price-wise, vinyl has become popular. There are two kinds of windows generally: Replacement windows, that are usually just installed by a glass company like us; and newly constructed windows, used for new homes and usually involves a contractor to install."

In addition to the basics of what windows are made of, insulating them is the next pressing problem. Up to 50 percent of heat is lost through faulty windows, according to the manufacturers of Window Man windows. This, of course, wreaks havoc on your winter heating bill. The 1970s oil crisis forced builders to investigate energy efficient methods in many aspects of homes, especially windows.

"Argon gas can be injected into the glass, if you''re in a really cold place or in shade. This improves the insulation performance," says Caronia. "There''s also a low-E film that can be applied to glass to keep air in when the heater is on, we call it ''smart glass.'' This also keeps the heat out on a hot day."

The ''E'' stands for emissivity, the measure of how much glass transfers radiant heat. Low-E film allows the sun''s energy to help heat the house through the window. Argon gas is more effective than air at reducing transmission of cold to warm air.

"When they first came out, many windows were half-inch thick insulative units. Now they''re one-inch thick with an insulating air space between the dual glass. More air space means more insulation. 90 percent of windows replaced are now dual-pane," Caronia says.

Some windows don''t open at all, some slide up and down, and some open like shutters. All have advantages and disadvantages. Like most housing design decisions, it comes down to your preference, unless there is a condition that warrants special conditions, such as windows facing the direction of bad weather, or the structure of the house not being able to support a certain type of window.

"Styles are dictated by the size of window you want and the type of house you have," says Putnam. "They can make a dramatic difference in the appearance of the house."

Besides the factors of energy and appearance, there are specialized problems that window companies can remedy more easily now. Between tinting the glass and putting in patterned glass, privacy issues should be fixed.

"If you have a sun or bright light problem, we can add a bronze or gray tint," says Caronia. "Some tints can give privacy so you don''t need to pull your curtains or blinds when you''re home," he adds.

ABC Glass frequently is asked for patterned glass, says Putnam. "There are opaque glass patterns, which are put in bathrooms or kitchens, or front doors where you don''t want people peeking in. A common one is a fern-leaf pattern."

Why replace windows? Lack of satisfaction usually comes from areas such as cracked paint and glazing, lack of energy efficiency, and the difficulty of cleaning, according to the Pella Window manufacturer. Putnam says newly installed windows can make a difference with sound proofing and in keeping moisture out of the house, which reduces mold and allergies.

Just as styles and options are wide ranging, costs depend mostly on the size and type of window. "Most windows are made-to-order now, they''re not just pulled off a shelf," says Caronia. "There are standard sizes, three-by-four feet generally, but most are made for certain orders. The same with glass doors. Cost is based on the size, of course. A four-by-three-foot replacement vinyl window is $180-200 per window, plus $70-110 for installation depending on the job. We install it and then it gets trimmed to match the interior of the home."

"It all depends on framing materials, size, the type of glass," says Putnam. "It could go anywhere from $60-800."

Be it one pane or three floors of glass, a window can be the finishing touch that brings light to your house, enhances curb appeal if you ever sell and creates more washing opportunities for you. H&G