Window Safety Locks (UPVC)
Handles & Hinges UPVC Maintenance Ltd is a UK specialist in replacement parts for UPVC windows and doors. We help homeowners, trades and housing providers choose the right safety hardware — clearly measured, properly fitted, and easy to use.
Window safety locks do two jobs: deter forced entry and protect people inside (especially children and vulnerable users). Below are the common options used on double‑glazed UPVC windows and when to choose each one.
Types of window safety locks
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Locking window handle
The simplest factory‑style solution. Modern espag or cockspur handles lock when shut (or via a push‑button/key), preventing the handle being “jockeyed” from outside. Quick to check at night: if the handle is fully down, it’s locked. -
Sash jammer / swing arm
A small swing‑bolt fixed to the frame that physically stops the sash opening. Great as a belt‑and‑braces add‑on or a short‑term secure‑up if the main lock is faulty. Installs with a couple of self‑tapping screws. -
Concealed (self‑engaging) restrictor
Fits between sash and frame and engages automatically when closed. To open wider, press/release the arm. Ideal where there’s a risk of falls — adds everyday safety while allowing full opening when intentionally released. -
Fixed restrictor
Limits the opening to a set gap and is meant to stay in place. Use pairs to prevent prying. Common in hotels, stadiums and care settings where preventing full opening is the priority.
Quick comparison
| Type | Best for | Opens fully? | Fitment | Notes |
|---|---|---|---|---|
| Locking window handle | Everyday security | Yes (when unlocked) | Handle swap/upgrade | Insurance‑friendly; key or snap‑shut variants |
| Sash jammer / swing arm | Extra “belt & braces” / temporary secure | Yes (swing to release) | Frame‑mounted | Simple, low‑cost deterrent |
| Concealed restrictor | Child safety / fall prevention | Yes (press to override) | Between sash & frame | Self‑engaging on close |
| Fixed restrictor (pair) | Permanent opening limit | No | Sash & frame fix | Ideal for hotels, care settings, stadiums |
FAQ
Which option is most secure? A locking handle is your first line, often preferred by insurers. Add a sash jammer if you want extra resistance.
Can a restrictor be overridden in an emergency? Concealed restrictors have a release so you can open fully when needed; fixed restrictors are for permanent limitation.
Will these fit UPVC windows? Yes — the options above are designed for UPVC frames and install with self‑tapping screws. Check clearances and follow the fitting instructions.