What is the actual function of the lock on a up can window handle?

Question

I have upvc windows with the typical handle with push button and lock which rotates ninety degrees to engage/disengage the locking mechanism (3 bolts in the bottom of the window frame which engage with plates along the sill).
What I can’t work out is the actual purpose of the embedded lock in the handle (with key). When locked, it prevents the handle being used,  and this might be useful for security from the inside (eg if a toddler is roaming about) but it doesn’t seem to increase the security vs an attack from the outside.
Am I right or am I missing something?  Insurance companies seem to require these locks, I think, which suggests they have some purpose but I can’t see it.
One of my windows was recently levered open from the outside, which snapped the 3 plates on the sill. The embedded lock in the handle seems of no value to protect against this activity. Or am I being dumb?

Ecnerwal · Accepted Answer

The intent of the handle lock is that "break window, open handle so you don't have to climb through the jagged glass left in the frame, climb in opened window" is made difficult.
If the lock plates are too weak and snap when pried, that case gets no help from the handle lock.
Sad reality is that if a thief wants in, they will get in - "security" is just slowing them down or making things more difficult for them.

What is the actual function of the lock on a up can window handle?

One Answer

Add your own answers!

Ask a Question