Because you still need to move air around, if not just for comfort and removal of stagnant air, then for the fact that the moisture you produce now will otherwise remain in the structure and be there for any autumn/winter mould/condensation.
Presumably you had this fitted for a reason ... poor ventilation or a condensation problem?
If not, and the existing ventilation is adequate then perhaps it can be unused ... but then that begs the question why was it fitted in the first place?
It was installed to remedy a condensation problem, but during the summer obviously we have the windows open a lot of our windows open, so it appears to be counterintuitive
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local