I have bought some trickle vents to put onto my double glazed UPVC windows. However, my windows have never had trickle vents fitted before and I can only guess by looking at the product, that I need to drill a few holes into my windows, outside to inside. Is this okay to do???
I have bought trikle vents because of condensation problems downstairs in my three bed semi. I am unable to leave any of the windows open to let the air flow.
Is this the correct thing to do???