Window frame or sash - trickle vents?

[jeff268]

Hi all..

Forgive me if this has been asked before but I wondered whether someone could answer a simple question for me.

I recently had new windows fitted and noticed after the event that they didn't install the trickle vents post June 22 regulations. The company were apologetic and said they would fit them retrospectively to the top of sash part of window(the opening part of the window side as per pic) . I read that the trickle vents have to be installed in the  * window frame* as of June 22...is this incorrect? 

[HughF]

I’d keep quiet if I were you… why would you want an uncontrollable hole in your new, sealed, window?

[Redbeard]

I doubt there is a difference between a hole in the sash and a hole in the top rail, but the top rail appears to have mmore 'meat' - unless there is a bigger 'downstand' on the outside). Why would you want to fit a trickle vent into a tight space on the sash instaed of a more generous space on the top rail of the main frame?

 

@HughF asks an understandable Q, but one answer could be 'as part of a thought-out decentralised mechanical extract (dMEV) system' (if MVHR is beyond the pale).