PVC windows have a built-in adjustment system that lets you fine-tune how firmly the sash presses against the frame — tighter in winter to block drafts, looser in summer to ease wear on the seals. Most people never touch these settings. Ten minutes with an Allen key twice a year makes a real difference.
Why seasonal adjustment matters
The frame and sash expand in summer heat and contract in winter cold. A fixed clamping force year-round means either the rubber seal wears out too fast under constant pressure, or cold air sneaks through gaps in winter. Seasonal adjustment balances both and extends the life of your seals by years.
What you need
- Allen (hex) key — usually 4 mm or 5 mm
- Occasionally a flat-head screwdriver, depending on the hardware type
- 10–15 minutes per window
How to adjust — step by step
Side hinges control how the sash sits against the frame. Find the adjustment screw on each hinge — usually on the side or bottom. Turning clockwise increases clamping pressure (winter mode); counterclockwise reduces it (summer mode). Adjust each hinge by the same number of turns to keep the sash aligned.
The locking pins (mushroom cams) around the sash perimeter also adjust. Insert the Allen key and rotate: the slot indicates clamping direction. Angled toward the frame means higher pressure for winter; parallel means lighter contact for summer.
When adjustment alone is not enough
If the window still drafts after adjustment, the sash is visibly warped, or the hinges feel loose and grinding — the problem goes beyond a hex key. Same goes for seals that have hardened, cracked, or flattened: clamping pressure cannot fix a seal that no longer seals.
In Warsaw apartments, especially those fitted in the 2000s, hardware often wears out while the frames themselves remain fine. A professional check can save you from an unnecessary full window replacement.
How often to do it
Twice a year is enough: before the heating season (September–October) and after it ends (April–May). While you are at it, inspect the seals and hinges — small issues caught early cost far less to fix.
If you would rather have a professional handle all the windows in one visit, leave a request through the form on our site. The cost depends on the number of windows and the scope of work.