Worried about children climbing out, or want to leave a window open safely? A window restrictor limits how far an opening window can open, so you can let fresh air in without the gap being big enough to fall or climb through. We stock concealed window safety catches, lockable cable restrictors, tilt & turn and ventilation restrictors and sash jammers for uPVC, aluminium and timber windows, from Window Ware, greenteQ, UAP, Securit, Maco, Mila, Boa, Fab & Fix and Penkid.
Most window restrictors fit with a few screws. Check the type, the gap between the sash and frame, and whether the window is also a fire escape before you order.
Fitted between the opening sash and the frame, so they're hidden when the window is closed. The window stops after opening a short way, and an adult presses a release to open it fully. Check the stack height (the gap between sash and frame) and frame width on the listing.
A short steel cable between the sash and frame, usually locked with a key. Visible, easy to fit on most uPVC, timber and aluminium windows, and can also be used on doors.
For tilt & turn windows that open inwards, and restrictors that hold the window slightly open for ventilation while limiting the gap.
A lockable lever fitted to the frame that swings over the edge of the sash, adding an extra locking point to a uPVC or timber window or door. Popular for extra security on ground floor windows.
Window child locks and restrictors are one of the simplest ways to reduce the risk of a child falling from an upstairs window. They are widely used in homes, rented properties, schools and care settings, and let you ventilate a room without leaving a window wide open. A common child-safety guideline is to restrict the opening to around 100mm.
If a window is also a fire escape, an adult must be able to open it fully and quickly in an emergency. Choose a restrictor an adult can release easily, and if it locks with a key, keep the key close to the window but out of children's reach. Never lock an escape window shut.
Hold the restrictor in position with the window closed, checking the window still shuts and locks properly. Mark the screw holes, fix the frame part and then the sash part, and test that the window stops at the restricted position and releases fully. On uPVC windows use the screws supplied and avoid drilling into the glass or the locking mechanism.
A window lock stops the window opening at all. A window restrictor lets it open a limited amount, so you get ventilation while keeping the gap small. Some restrictors can also be locked.
Yes. Concealed safety catches and cable restrictors are both designed for uPVC windows. Check the stack height and frame size for concealed catches.
Some do and some don't. Cable restrictors are usually key-locking; many concealed catches release with a push button. Replacement restrictor keys are available for some models.
No. A sash jammer adds an extra lock to stop the window or door being forced open. A restrictor limits how far the window opens.
Looking for a replacement locking mechanism or handle? See our window locks and window handles.
Not sure which restrictor fits your window? Send us a photo of the window open, with a tape measure across the gap between sash and frame, and we'll point you to the right one.
Send us a photo to identify your partMonday to Friday, 8:30–12:30 and 13:00–15:30
