Hi,
amazing what a change in the weather can bring.
Instead of worrying that the fan was not clearing hot air fast enough, I can now feel a cold draught coming in through the fan.
I have looked for an external vent which has a one way flap, but Screwfix at least do not seem to offer one.
I am also concerned that any such arrangement would require a reasonable positive pressure to open the vent, and so would cut down on the effeciency of the fan.
Is there a good one way valve for an extractor fan, or would you need powered (or cord activated) shutters on the fan body itself?
I can remeber the old VentAxia window fans where you pulled a cord and the shutters opened and the fan went on, and also have vague memories of powered versions which opened the shutters automatically.
Brrrr....soon be Christmas.
Dave R