Casement vs sliding windows is one of the first choices in any window order. A casement window has a sash hinged at the top or side that swings outwards; a sliding window has panels that glide sideways on a track. Both come in aluminium with the same glass and colours, but they differ in airflow, rain, space and price. This guide compares them side by side and shows where each works best.
In this guide
What counts as a casement window
In South Africa, “casement” usually means a hinged aluminium window: a top hung window, hinged at the top, or a side hung window, hinged at the side. Both open outwards on stainless steel friction stays. See top hung vs side hung windows for how those two compare.
Casement vs sliding windows at a glance
| Casement (top or side hung) | Sliding | |
|---|---|---|
| How it opens | Swings outwards | Panel slides sideways |
| Airflow | A side hung sash opens almost fully | About half the window opens |
| Light rain | A top hung vent can stay open | Close it |
| Outside space | Needs room for the sash to swing | Nothing projects |
| Wide openings | Vents plus fixed glass | 3 or 4 panels up to 4 800 mm |
Airflow and rain
Airflow is where casement vs sliding windows differ most. A side hung sash opens almost its full height, so it lets in the most air for its size. A top hung vent opens less, but its canopy shape sheds light rain, so it can stay open in a shower. A sliding window opens only where a panel slides away, roughly half the window on a 2 panel unit, and should be closed when it rains.
Space inside and out
On space, casement vs sliding windows trade places: sliding windows win where space is tight. Nothing swings out, so they suit windows beside paths, braai areas, balconies and parking bays, where someone could walk into an open casement. Casement windows need clear space outside for the sash to swing. Inside, both stay within the frame.
Price
All 1 200 × 1 200 mm, White, excluding VAT, at the time of writing (October 2026):
| Window | Price |
|---|---|
| Top hung, single opener | R3 475 |
| Side hung, single opener, 900 mm sash | R3 468 |
| Sliding, 2 panel, Standard | R4 952 |
| Sliding, 2 panel, Horizon | R9 863 |
| Sliding, 2 panel, Premier | R11 948 |
On price, casement vs sliding windows is a clear win for casement at standard sizes, and Premier and Horizon sliding windows cost more again for their heavier systems. See aluminium sliding window sizes and top hung window sizes.
Where each works best
When weighing casement vs sliding windows room by room:
- Bathrooms: top hung, for ventilation in any weather. See aluminium bathroom windows.
- Bedrooms: side hung for maximum airflow, or sliding beside a path.
- Kitchens: sliding windows are easy to open over a counter. See aluminium kitchen windows.
- Living rooms: wide sliding windows, or a 4-pane top hung window.
- Exposed walls: top hung, which can stay open in light rain.
Mixing both
Most houses use both, and they look at home together when the frames share one colour. A common mix is top hung in bathrooms, side hung in bedrooms and sliding in the kitchen and beside walkways. Choosing between casement vs sliding windows is about each opening, not the whole house.
Glass, colour and ordering
Both types use 6.38 mm clear laminated safety glass to SANS 10400-N, published by the South African Bureau of Standards, and come in White, Bronze, Charcoal, Black and Natural Anodised. Coetz™ supplies them ready to fit; your builder or installer fits them. We deliver across South Africa, or you can collect free from Laser Park. See aluminium sliding windows and top hung aluminium windows.
Casement vs sliding windows: frequently asked questions
Which lets in more air, casement or sliding windows?
A side hung casement window, because its sash opens almost fully while a sliding window opens about half.
Are sliding windows cheaper than casement windows?
Not at standard sizes: a 1 200 × 1 200 mm top hung window is R3 475 against R4 952 for a Standard sliding window.
Which window is best beside a path?
A sliding window, because nothing swings out into the walkway.
Can I leave a window open in the rain?
A top hung window can stay open in light rain; close sliding and side hung windows.
Can I mix casement and sliding windows on one house?
Yes. Use one frame colour throughout and the two types look at home together.
Coetz™, Unit 2, 84 Ridge Road, Laser Park, Johannesburg. Call 010 412 0062, WhatsApp 076 613 4418 or use our contact page.
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