Casement and sliding are the two most popular uPVC window styles — and the right pick usually depends on the room, not personal taste. Here is how they compare and where each one shines.
How they open
Casement windows are hinged and swing open like a door, so the whole opening clears for airflow. Sliding windows glide sideways on tracks and never project in or out.
Airflow and sealing
Casement windows open fully, so they ventilate better, and when shut they compress against the seal — giving the tightest defence against rain, dust and noise. Sliding windows ventilate about half the opening at a time and rely on brush seals, which are good but not quite as airtight.
Space
Sliding windows win where space is tight — balconies, passages, or anywhere a swinging sash would get in the way, because they take no swing room. Casements need clearance to open.
Views and cleaning
Sliding windows give wide, uninterrupted views and are easy to operate. Casements let you reach the outer glass by swinging the sash in, which makes upper-floor cleaning simpler.
Cost
Sliding windows are usually a little more economical; casements use more hardware, so they sit slightly higher. See the ranges in our price guide →.
Room-by-room recommendation
- Bedrooms & living rooms — casement, for the best airflow and the quietest, tightest seal.
- Balconies & passages — sliding, to save space.
- Kitchens — either; sliding if the counter is right at the sill.
- Road-facing rooms — casement with double glazing, for maximum noise control.
Most homes use a mix — and Astrapia makes both to your exact opening. Get a free measurement →.
Frequently asked questions
Which is better for security?
Both are secure with multi-point locking and steel-reinforced frames. Casement multi-point locks pull the sash tight into the frame all round.
Which is better in heavy rain?
Casement windows generally seal tightest against driving rain; good sliding windows with proper drainage also perform well.