Thanks bro. I have done a few searches and i have noticed houses in general are very brightened up on the pictures i have seen.

In my loft, the bottom of it where the roof is, i have left that part free see there is a 1cm gap between the fibre glass on the tilted roof and the floor. This might let heat escape, and this also is my ventilation .

But i am still very worried because I know ALL people that live near me, and most of them smoke marijuana but dont grow.

Note : They all live in houses like me.