A window restrictor is a safety device which prevents a window from opening more than a fixed distance. 

Have a look at our Buyer's Guide to help you make a more informed choice.

Introduction

A window restrictor is designed to eliminate the risk of injury caused by falls from windows by restricting the opening of a window. 

The fixed distance is set to prevent anybody from getting in and out the window and important for people who are at risk of falling out of them and sustaining a serious injury. 

For places at ground level, window restrictors also help provide some security whilst having the window open but they are not considered as secure. Any open window can never be treated as secure although with window restrictors it’ll obviously slow down any intrusion.

Types

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TypeDescriptionProsConsCost(Avg)Idea For
Cable restrictor Cable Lock

This type of restrictor limits the distance a window can be opened via a cable attached to a lock. The cable and lock would be fastened by metal plates attached to the different frames of a window using screws.

When the cable is in place the distance the window can open is limited, by using the key the cable can be removed from one end and the window can be opened fully.

In order to open the window fully, a key needs to be inserted to unlock and release the cable.

  • Fit to All Windows
  • Cable tensile strength can withstand stronger forces than other options
  • Require to drill holes in the window frame
  • When window is closed, restrictor  Cable might get caught on by things

$50/piece

(includes installation)

Quick Estimate
  • Swing window
  • Sliding Window
Ventilation lock UPVC Restrictor Hook Safety Catch Restrictor

Usually made from Stainless Steel, this type of restrictor has no need for keys, it's self engaging & quick to release in an emergency.

They are fully concealed, when the window is closed. 

The restrictor arm is fixed to the actual window opening sash and the stud to the frame.

  • Concealed when window is fully closed
  • Require to drill hole in window frame
  • Not as strong as other options
  • Does not fit to all types of windows, retrofitting might be required.

$60/piece

(includes installation)

Quick Estimate
  • Swing window
Key release restrictor

There are multiple variants of such types of restrictors, but with similar functionality.

This type of restrictors, can be released to allow full opening of the window using a key.

They are fully concealed, when the window is closed. 

The restrictor arm is fixed to the actual window opening sash and the stud to the frame.

  • Concealed to side of window
  • Added security with the use of a key for full release
  • Require to drill hole in window frame
  • Not as strong as other options
  • Does not fit to all types of windows, retrofitting might be required.

$79/piece

(includes installation)

Quick Estimate

Swing window

Action release restrictor

This type of window restrictors will require a specific step, like pressing a button or lifting a cache to release the restrictor for full opening of the window. 

They are not concealed and are typically installed at sides of windows where access to the release mechanism is within reach (or higher to prevent access by children).

  • Fit to All Windows
  • Added security with  need to manually release restrictor
  • Release mechanism is still within easy access and not be ideal for families with toddlers (although this can be positioned higher to limit reach)
  • Visible and require space at the window. Might obstruct window treatments (e.g. blinds) if the gap is too narrow.

$40/piece

(includes installation)

Quick Estimate
  • Swing window
  • Sliding Window
Retractable Restrictor

This type of restrictor limits the distance a window can be opened via a cable attached to a lock. 

When fully closed, the restrictor cable is retracted hence avoiding risk of getting caught on by things.

When the cable is in place the distance the window can open is limited, by using the key the cable can be removed from one end and the window can be opened fully.

  • Fit to all windows
  • Cable tensile strength can withstand stronger forces than other options
  • When window is closed, restrictor  Cable is retracted hence avoid risk of getting caught on by things
  • Require to drill holes in the window frame
  • Visible and require space at the window. Might obstruct window treatments (e.g. blinds) if the gap is too narrow

$85/piece

(includes installation)

Quick Estimate
  • Swing window
  • Sliding Window
Window Track Lock

A track stop is a locking stop that you can attach anywhere on a sliding window track. 

It can be positioned to lock the window shut, or so that the window only opens a certain amount, enabling ventilation and safety.

A key is required to unlock the restrictor and would require a locking plate to be mounted to the window track.

  • Fit to All sliding Window track
  • can withstand stronger forces than other options
  • Require to drill holes into track

$70/piece

(includes installation)

Quick Estimate
  • Sliding Window
Sash Lock Restrictor

Similar to the track locks, these types of restrictors can be positioned anywhere on the window track to lock the window shut, or so that the window only opens a certain amount, enabling ventilation and safety.

They do not require drilling of holes in the track.

  • Easy to install
  • Cheapest option for sliding windows
  • Not as strong as other options
  • Sliding window

Buying Considerations

  • Durability of the restrictor - If intent for restrictor is to ensure accidental fall, then how much force a restrictor can withstand is very important. It should minimally support 30kg of force. And that the latch or locking system housing should be made of materials that are tamper proof. Typically concealed type restrictors would not withstand as much force as a visible one.
  • Intended usage - If intent is to ensure a child doesn't accidentally free the restrictor, open and fall through the window, then a restrictor with a locking system is important. If the choice is to go for action release restrictors, then location of the restrictor should be out of reach of the child. If the window to restrict is meant for fire-escape, and with no worries of child safety, a ventilation lock would be a good consideration. They do not need keys, and have a quick to release mechanism, best for emergency cases.
  • Concealed or visible - If the window sill is very narrow where a restrictor cannot be installed, or risk blocking other objects (like curtain), then do consider concealed options. Of course this should always be balanced with the intended usage of the restrictor and priority for child safety.

FAQ

Technical Terms

  1. Stud plate - These are the stationary metal plates that will be mounted on the ledge of  window frame to hold the restrictor in place . For example,  stud plate for the cable restrictor holds the cable in place.
  2. Locking system - Part of the restrictor where you the restriction can be locked in place to limit distance a window can be open.
  3. Steel cable - Comes with a cable restrictor model, this steel cable will  limit distance a window can be open. Different vendors will have different loading tension for this cable (typically it should  support up to 200kg before breakage.
  4. Window sash - Sash is the moveable part of a window that holds the glass.
  5. Bottom rail - A rail is the horizontal piece of a window sash.  The bottom rail is the lower part of the sash.
  6. Hinge channel - The hinge channel sits across the bottom of the window sill. This is where the  The window crank mounts to the channel, and the bottom edge of the sash attaches to the channel.
  7. Window sill - A window sill, also known as a window ledge or window bottom, is the shelf-like, flat piece of the window trim found at the base of the window.