"Andy Burns" wrote in message
...
tim... wrote:

Tim Streater wrote:
And avoid trickle vents if you can

now a mandatory requirement

Only mandatory if what they are replacing already has trickle vents.

Not sure it's that simple

Surely the rule is that the room must be provided with sufficient
ventilation

If a room previously didn't have trickle vents because it already has air
vents, then you might be right

but where the ventilation in the room was previously provided by "leaky"
widows (which is virtually a given for all old fashioned windows) and you
are replacing them with windows that provide a leak free environment, then
trickle vents must be installed