Horizontally-mounted windows have one or both sashes that slide past each other on a track, providing plenty of light and ventilation for your money.

Pros: Easy to open and clean; low cost; trouble-free.

Cons: Can only open half the window at a time; sills can fill with rain if drainage holes become plugged.

Cost: $250-$950 for a 5-foot-by-4-foot window.

Image: Jeremy Krill Construction

Often installed above a kitchen sink, a garden window is a mini-greenhouse with a clear, slanting top, a fixed window in front, two venting side windows, and one or more shelves. They’re great for growing herbs year-round and displaying your pottery collection.

Pros: Adds fresh air, light, warmth, and storage space.

Cons: Increases solar heat gain. Fix: Buy high-quality garden boxes with insulated, low-E glass.

Cost: $1,000 (aluminum) to $1,200 (vinyl). Add 10% to 20% for low-E glass and tempered glass.

Image: Ashford Associates

Double-hungs, the nation’s most popular window, feature two sashes that slide up and down. They’re especially well-suited for vertical window openings.

Pros: Many styles, colors, and materials to choose from; tilt-out models are easy to clean; accommodates screens and air conditioners; low cost.

Cons: Often leaks air without souped-up weatherstripping; limited ventilation.

Cost: $200-$600 for a 3-foot-by-5-foot window.

Image: Southern Belle Vacation Rentals

You’ll get a better night’s sleep with these custom, sound-deadening windows. They have an extra pane of heavy glass that reduces noise by as much as 30% over regular insulated-glass windows.

Pros: Blocks street sounds; great near airports and freeways; adds thermal insulation and reduces energy bills.

Cons: Added cost; extra cleaning; additional glass means window sashes are extra-thick, virtually eliminating the interior sill.

Cost: $400-$900 each.

Image: Quiet Line Sound Control Windows by Milgard

This multi-section window assembly adds class and square footage to any room. Build a window seat below and you’ve got comfy seating and extra storage.

Pros: Increased sunlight, storage, and ventilation; handsome interior feature.

Cons: Costly repairs can require replacing the entire unit; large glass area increases heat loss and gain.

Cost: $1,000-$8,000, depending on the size of the window and complexity of the job.

Image: Gowercroft Joinery

Easy-open casement windows are side-hinged and crank-operated. Because the entire sash swings to the side, casements provide maximum breezes and views.

Pros: Increased ventilation; closes tightly to prevent energy loss; unobtrusive hardware.

Cons: Large casements can weigh themselves down and become hard to close and latch; cranking mechanism can break easily; won’t accommodate storm windows; screens are on the inside.

Cost: $200-$500 for a 4-foot-by-5-foot double-sash window.

Image: Gowercroft Joinery

Now you see ‘em, now you don’t. Bifold windows have hinged sashes that fold up to provide a clear view of the great outdoors. Bilfolds also can be installed in an interior wall to separate spaces and reduce noise flow when needed.

Pros: Wide, unobstructed view; good ventilation.

Cons: Lots of moving parts to clean and maintain; increased heat gain and loss; wicked expensive; may require structural alterations.

Cost: $2,320-$2,530 for a 3-foot-by-8-foot window.

Image: Peter Stames at Archia Homes

Want to brighten small spaces? Awning windows pivot on top-mounted hinges and open out from the bottom, saving space. You can also open them in bad weather, because rain runs down and away from sashes, keeping the inside dry.

Pros: Increased light and ventilation; cost-effective; secure.

Cons: May obstruct outside walkways; need frequent cleaning.

Cost: $320-$550 for a 3-foot-by-2-foot window.

Image: BUILD LLC

These roof windows shed light on rooms and hallways. Some open by crank or by motor, although opening skylights increases your chance of air and water leaks.

Pros: Adds natural warmth and brightness; increased ventilation; lowers heating bills.

Cons: Can be leaky, drafty, hard to clean, and costly to install; fancy options, such as rain-sensing auto closers, add to the price.

Cost: $150-$500 for window and flashing; $500-$3,000 for installation.

Image: VELUX America

These decorative glass windows are pieces of art that claim center stage in any room. Add stained glass over your entry door to make a dazzling first impression.

Pros: Attention-getter; lets light in; keeps prying eyes out.

Cons: Obstructs views; prone to overkill (a little stained glass goes a long way); a permanent reminder of your previous bad taste in art.

Cost: $125-$550 for retail panel; $95-$125/sq. ft. for custom stained glass (ballpark because each artist has his own pricing).

Image: Valerie Batt Painted Light Stained Glass

No more dusting and fussing with blinds when they’re sandwiched between two panes of glass. Some have traditional adjustment cords; some are magnet-moved; and some have motors to position your blinds just so.

Pros: Largely dust-free; little kids and pets can’t mess with the slats; classy look.

Cons: Expensive; limited styles and colors; cumbersome and costly to repair; energy efficiency claims are arguable.

Cost: $850-$1,050 for a 3-foot-by-5-foot window.

Image: Pella Windows and Doors

Sea turtle hatchlings instinctively follow moonlight into the ocean to live their lives. But indoor lights confuse them and encourage the babies to crawl onto land toward certain doom. Turtle glass windows are grey-tinted to reduce visible light pouring out of the house.

Pros: Helps protect sea turtles and sea ecology.

Cons: Costly; low light can make walking outdoors hazardous.

Cost: $370-$550.

Image: Photo Courtesy of Simonton Windows