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Window & door types

All window types

Sliding window

One or both sashes glide horizontally along the track without projecting inside or outside.

Sliding window

Drag or press ← → to rotate; Home resets the view

Pick a window or door type, drag or use ← / → to rotate the 3D model, and press the mechanism buttons to see how it opens.

How it opens and how it is built

The sashes sit side by side in the frame, and a moving sash glides along a track at the bottom and a guide at the top, past the other sash. Weatherstripping along the track and where the sashes meet closes the gaps, and a latch holds the sash shut.

The window opens in the plane of the wall, so nothing swings into the room or out over a walkway, and a moving sash can usually be lifted out of its track to be cleaned. In the 3D model above you can check how the sash slides open.

Why you'd want it

A sliding window suits openings that are wider than they are tall: one long horizontal sash is easier to move than a tall vertical one, and it takes no space inside or outside the wall.

A single-hung opens up instead and suits tall, narrow openings. A casement swings out on hinges, opens almost the whole sash and closes tighter, but needs room outside.

Pros and cons

Pros

  • It opens without sticking out, so it suits windows next to walkways, patios and decks.
  • A long horizontal sash is easy to move, with no crank and no balances.
  • It fits wide, low openings that would need very wide vertical sashes otherwise.

Cons

  • Only part of the opening opens, about the width of the moving sash.
  • The bottom track collects dirt and needs regular cleaning to keep sliding smoothly.
  • Its sashes slide past their seals, so it usually seals less tightly than a picture window or a casement.

It's for you if…

  • The opening is wider than it is tall, for example over a bed, a sofa or a kitchen counter.
  • The window looks onto a patio or a walkway where a sash that swings out would be in the way.
  • You want a window that is easy to open without cranks or lifting.

Don't overpay if…

  • The opening is tall and narrow: a single-hung suits it better and costs about the same.
  • The spot is very windy and you want the tightest closing window that opens: a casement presses against its seal.
  • You need a way out to the yard: a sliding patio door is the door version, not a larger window.

How it affects the price

A sliding window is usually one of the less expensive opening windows: the sash glides in a track with a simple latch, without a crank, hinges or balances. It is usually close to a single-hung of the same size and costs less than a casement.

Within the type the width, the number of sashes, the frame material and the glass unit move the price.

All window types and their impact on the price →

Lifespan and care

Each season, vacuum the bottom track, wipe it clean and make sure the drain holes in it are clear. Once or twice a year check the weatherstripping along the track and where the sashes meet, and lubricate the track lightly if the maker advises it. A sash that drags usually needs a clean track or new rollers, not a new window.

Figures with sources

How the sashes move
Sliding windows have sashes that slide from side to sideSource:Window Types — NFRC Consumer Guide to Windows (Efficient Windows Collaborative)
What else is in the same category
This category includes sliding doors common for yards and patiosSource:Window Types — NFRC Consumer Guide to Windows (Efficient Windows Collaborative)
Which family of opening windows it belongs to
the sliding types such as double- and single-hung and horizontal slidingSource:Types and Parts — NFRC Consumer Guide to Windows (Efficient Windows Collaborative)

What it pairs with

A sliding window works with any glass unit, and a Low-E coating suited to your climate matters more for comfort than the type. The frame material decides how stiff a long sash stays, and the hardware — the rollers and the latch — how smoothly it slides and how well it closes. How the window is set into the opening decides how well it seals.

Which glass unit to choose →How a window is installed →

Compared with similar types

Frequently asked questions

How much of the opening opens?

About the width of the moving sash, because it slides over the sash next to it. A window with a moving sash on each side lets you open either side, but not both halves at once.

How do I take care of the track?

Vacuum out the dirt and wipe the track each season, and keep its drain holes open so water can leave. If the maker advises it, a light lubricant on the track keeps the sash sliding easily.

Is a sliding window drafty?

It usually lets through more air than a picture window or a casement, because its sashes slide past their seals. A good weatherstripping and careful installation keep it comfortable; compare the air leakage on the NFRC label if the maker lists it.

Is it a good fit for a wide, low opening?

Yes, that is where it works best: over a bed, a sofa or a counter, where a tall sash would be hard to reach and a sash that swings out would be in the way.

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