Room ventilation requits when installing windows and opinion

[cerclebois]

A relative is having his property's aluminium windows replaced by PVCU. From the time I had mine done a while back, I recall that the installer changed the configuration from what it was previously to fit with the then room ventilation regulations. The earlier windows were IIRC over specified.

So that the relative avoids paying over the odds for what may not be necessary, can any one advise what the requirements are for each kind of room; please?

Do you recommend these products: Duraflex; Eurocell; Rehau, and what is your preference?

 

[Gazman16]

Those are all good makes but personally I prefer Eurocell or Liniar for the way they look.

As for vents you only require them if:
The window being replaced had them.
On a newbuild.
If there is a gas appliance in the room that dosent have its own vent.

These rules may only apply to a Fensa registered company. If they are being signed off by building control they may want vents on all of them.