My double glazed windows can be locked slightly open – is this as secure as when the window is fully shut?

My first thoughts were that a burglar would be able to get extra purchase with a crowbar but the amount of force required to break the locking mechanism would be the same regardless and it would be easier to just break the glass.

Breaking glass noise will alert neighbours hopefully, forcing the window open from the other side of the lock will require little force as you only need to overcome a small plastic wedge usually, trickle vents are better for ventilation.

My schoolboy analysis would conclude that locked shut is much better than locked open.

So is the window more secure locked fully shut as opposed to slightly open and locked, or is forcing open a locked uPVC window from the outside easy either way?

To be clear, there are 2 sets of slots within the casement that the mechanism locks in to about 10mm apart – the nearest set are when the window is firmly shut, and then the second set allows ventilation but uses the same locking mechanism.

From the outside its not flush, but you’d struggle to get anything rigid through the gap between window and frame – perhaps 3mm of air gap.

When locked in vent mode is it less secure or the same?

Ta

When the window is locked in vent mode have a look ouside and youll see the other side is slightly away from the frame, the gap will be big enough to insert a screwdriver or scally bar a small crow bar and some force will crack the wedge that pulls the window closed to the frame have a play and see.

Vent mode allows a gap big enough to insert a tool and apply force.

So it should only be considered as a child safety lock at best?

Crack the metal wedges ? More likely to destroy the window first.

Still sounds quite destructive – I guess the front windows will be ok, but those at the side / back where its more out of site are vulnerable.

Just wondering if it would be seen as an easy way in.

Is my burglar alarm bell box likely to put them off?

We have the same design on ours, can’t see anyone breaking in without a large crowbar and some serious effort.

We’ve the same set up pieface. Find them really handy.

Don’t mind leaving the upstairs locked open while not in the house (on a hot day/just left something stinky before I left) but only leave the downstairs locked open when we are in (on a night).

As above, does leave a small 5/10mm gap outside so a scumbag could get something in to prize open. It’s not obvious when they are locked open.

Are there similar vent mode options for tilt and turn windows?

Just had a couple of t&t’s installed, and in tilt mode they are either fully shut or fully open, with about a 5degree tilt. When open in tilt mode, its enough so that the rain gets in to the window returns. There doesn’t seem to be a method of locking them only just open.

Also, similar question to the OP, how secure are they when opened in tilt?

Still sounds quite destructive – I guess the front windows will be ok, but those at the side / back where its more out of site are vulnerable.

Folks were broken into many moons ago – the UPVC flexes and they actually managed to lever the window OVER the latch and got it open. Suffice to say, some very stern words has with window company…

Is my burglar alarm bell box likely to put them off?

Possibly, but don’t rely on it – some toerags set off my mates alarm. Police called by neighbours etc. etc. – no visible problem so left again. Scrotes came back an hour later, alarm went off again, everyone ignored as though it was a false alarm again.

Are there similar vent mode options for tilt and turn windows?

easy to fit trickle vents a series of holes bhing vent along top of window and trickle vents screwed on top both sides, any dg co will be able to fit them.

Thanks Project, but not really after trickle vents like that. More a locked almost closed option, seen it on many windows, but not on my tilt and turn.