New windows - dual trickle vents?

[DevlinT]

Hello all

I am having some new uPVC windows installed. The company has advised that in my bedroom the single window in there will require 2 x trickle vents - one for the top pane and another for the bottom. He mentioned something about the airflow but was very woolly. To me it didn’t make any sense. Does anyone know why this would be required? The room is a standard sized 2m x 3.5m.

Thanks

 

[ronniecabers]

Bottom?

And yes building regs dictate a certain amount of ventilation. 8000mm2 ea for habitable rooms in multi floor properties and 10000mm2 Ea in single storey properties. It maybe he needs to get a bigger tricklevent

 

[DevlinT]

Thanks @ronniecabers

Yes, that value is what he mentioned. I’m guessing that the single trickle vent doesn’t satisfy that therefore a second is required. This is the design which shows the two vents:

 

[ronniecabers]

Personally I'd go for a wide outer frame at the top and see if I could get the manufacturer to put two in the outerframe or a bigger vent, Trickle vents are supposed to be as high as possible