My observation from houses in malaysia is that builders usually install quite cheap windows without proper locks, only a handle which "clips" over the frame when closed. These are very easy to pull open from the outside with a crow bar or even your bare hands.

I would advise that if you have these cheap windows, change them for windows with actual locks in the frame. Better still, if you can afford it go for double glazing and/or tinting so it's difficult to bypass the lock by breaking the glass instead. And generally you don't need all the panels in the window to open. Say you have five windows all in a row, consider installing fixed panels for 2 or 3 which can't be opened.

As mentioned, alarm sensors on all the windows that can be opened are good too. You can get "glass breaker" sensors too which go off if they detect the sound of glass breaking (or some other loud bang).

I always feel a bit weary about installing grilles. What happens if there is a fire in the house and you need to escape through a window? It seems a bit risky to me.

PS I've just stumbled across a solution for people that want to have a breeze coming through their house but don't have a grille: http://www.locksonline.co.uk/acatalog/Rest...dow_Section.jpg
I wonder if we can get these locks in Malaysia? Or if we can get windows that open like this (not enough to let someone through, LHS of picture): http://pattayatradeframes.com/wp-content/u...n_windows_1.jpg

Anyway I hope this gives you some ideas as alternatives to grilles

Doesn't that defeat the purpose of the grille? A robber could come through the escape door right?

Of course a grille over a door can be opened. I thought you meant the grilles over the windows can be opened in an emergency. That was what I said was my safety concern with grilles over windows. Even if there are such grilles I would be a bit uncomfortable with the idea as I wouldn't carry the grille key with me all the time. To each their own though.

Grill keys have to be located near the grill itself but of course not reachable from outside, just like emergency exit door in factory or office building

OK fair enough. Anyway I think we are a bit off topic as my original post was focusing more on alternatives to grilles, as the TS said he isn't allowed to install them.

Made an appointment with a tint seller. Gonna install security tint

Last owner told me he already change the glass.

Dan, you are very lucky. It costs alot of money to change from regular window glass to tempered glass. Especially if it's a Semi-d.

Like Weikee said, if it's tempered, there should be etching on the edge / corners with the word 'tempered'.