Which window type seals the tightest?

Casement (and awning) windows seal by compression — the sash presses against the frame — so they are generally the most airtight, with the lowest air-leakage ratings. Double-hungs and sliders seal by sliding past weatherstripping and are a little leakier.

Which window type is best for a bedroom that needs egress?

Often a casement, because its whole sash swings clear so the clear opening is close to the full size. A same-size double-hung or slider opens only half at once, so its clear opening may fall short of the egress minimum.

Are sliding windows cheaper?

Usually yes. Sliders have few moving parts and are typically the least expensive operating style, which makes them popular for wide openings. The trade-offs are a less tight seal and a smaller clear opening for egress.

When should I use a picture or awning window?

A picture window is fixed and maximizes view and daylight with the best U-factor, ideal where ventilation is handled by nearby operable units. An awning hinges at the top and sheds rain, good high on a wall, in bathrooms, or paired with fixed glass.

Double-hung vs casement vs sliding: pick the right window type

Operating style decides how a window ventilates, seals, meets egress and prices out. Match double-hung, casement, sliding, awning and picture windows to each opening — it matters as much as the brand.

By Francesco Zinghinì

Frame material decides what a window is made of; operating style decides how it works — how it opens, how well it seals, how it ventilates and whether it can serve as an escape route. The three you will meet most often are double-hung, casement and sliding, with awning and picture windows filling specific roles. Picking the right style per opening matters as much as the brand.

Double-hung: the versatile default

A double-hung window has two sashes that slide vertically, and usually both tilt in for cleaning. It is the classic American window: it suits almost any architecture, ventilates from the top or bottom, and fits tight spots because nothing swings out into a walkway, deck or patio. Its limitations are sealing and egress. Because the sashes seal by sliding past weatherstripping rather than compressing against it, double-hungs are typically a little leakier than casements, and because only half the window opens at once, the clear opening for egress is smaller than the unit suggests — a point that matters for bedrooms, as the egress guide explains. For most rooms, though, the versatility wins.

Casement: the sealer and the escape hatch

A casement is hinged on the side and cranks outward like a door. Two things make it stand out. First, it seals by compression — the sash presses tight against the frame — so casements are generally the most airtight style, which shows up as lower air-leakage numbers on the label. Second, because the whole sash swings clear, a casement's clear opening is close to its full size, so a casement often meets egress where a same-size double-hung fails. The catches: the sash projects outward, so it cannot go where it would hit a walkway or a deck; the crank hardware is one more thing that can wear; and very large casements get heavy. They are excellent over kitchen sinks, in bedrooms that need egress, and anywhere you prize a tight seal and an unobstructed view.

Sliding: simple, wide, budget-friendly

A sliding (slider) window moves horizontally on a track. It has few moving parts, opens easily even when wide, and is usually the least expensive operating style, which makes it popular for wide openings and for rooms where a broad, low window suits the wall. Like the double-hung it seals by sliding rather than compressing, so it is not the tightest option, and only half opens at once, which limits its clear opening for egress. Sliders shine where the opening is wider than it is tall and budget matters.

Awning and picture: the specialists

An awning window is hinged at the top and swings out at the bottom, so it sheds rain and can stay open in a light shower — ideal high on a wall, in bathrooms, or paired above or below fixed glass. A picture window does not open at all; it is a fixed pane that maximizes view and daylight and, having no moving seal, tends to have the best U-factor and lowest air leakage of any style. Picture windows pair naturally with operable units on either side to combine a big view with some ventilation. Neither serves as an egress window on its own, since an awning's clear opening is small and a picture window does not open.

Cost and how to compare

Operating style affects price. Sliders and basic double-hungs sit at the value end; casements and awnings, with their crank hardware, cost a bit more; specialty and large fixed units vary widely. Compare two styles for the same opening with the window type compare tool — enter your own per-window prices and it returns the difference and the labeled bands — and price a specific type with the window cost by type tool. As a worked example, a casement at 700 dollars a window versus a double-hung at 500 is a 200-dollar-per-window premium; whether that is worth it depends on whether you value the tighter seal and the egress clearance for that particular room.

Choosing per opening

The right answer is rarely one style for the whole house. Use double-hungs where versatility and a flush exterior matter, casements where you need a tight seal or bedroom egress, sliders for wide budget-conscious openings, awnings up high or over fixed glass, and picture windows where the view is everything and ventilation is handled nearby. Match the style to the room's job, confirm egress on any sleeping-room window with the egress checker, and treat the price bands here as planning typicals to test against real written quotes.