What it is: A window that is hinged on the right- or left-hand side and opens outward with a turn of a crank handle.
Pro: It offers excellent ventilation. And since this model is sealed all the way around when shut, it boasts a low air-leakage rate and good noise reduction.
Con: Because it swings out, it won’t work near a walkway or a deck. The crank can get tedious.
Cost: About $185 to $1,000.
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What it is: This type features two sashes (movable panels) that slide vertically open and closed.
Pro: Opening both the top and the bottom creates a natural convection–cool air comes in at the bottom and warm air escapes out the top. Many models tilt inward so you can scrub the panes from the inside.
Con: The horizontal rail in the middle obstructs your view.
Cost: About $100 to $2,300.
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Fixed (or Picture)
What it is: It doesn’t open but offers unobstructed views.
Pro: A small one can brighten up a stairwell, while a large one showcases an amazing vista. A fixed window comes in many shapes. Plus, no drafts here: It’s completely airtight.
Con: You won’t get any ventilation, of course, and you’ll need to clean the exterior from the outside.
Cost: About $60 to $2,600.
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What it is: Similar to a casement but hinged at the top.
Pro: When extended, the glass slopes downward, so the window can be left open when it rains. It can be used as a clerestory (a window near the top of a wall) to let hot air escape.
Con: Offers only partial ventilation and is usually too small to use in the event of an evacuation.
Cost: About $100 to $1,100.
Tip: Check labels for a window’s U-value (aim for 0.35 or lower). The lower the number, the better its insulating property.
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What it is: A window with a moving panel that slides to the left or the right to open.
Pro: It is easy to open and doesn’t project outward, so it works well next to walkways and patios. The opening is usually big enough for an emergency evacuation. Fixed screens can be added.
Con: You can open only one side at a time.
Cost: About $80 to $930.
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What it is: A window installed in the ceiling. Some (called roof windows) are fixed; others open for ventilation.
Pro: Some come with remote-control blinds and coated glass that minimizes exposure to UV rays. If you have an attic, you can get sunlight into a dark closet or room via a tunnel-like skylight that runs to the space from the roof.
Con: You’ll have to climb onto the roof to clean the exterior.