Hello everyone ... in my building they cut the gas and demand, among other things, the Ventilation Grilles in each apartment. I know that by regulation it corresponds in my dept grid with a step of 100 cm2 one up and another down, now there is a 15x15 grid with 100cm2 and also 20x20 with 100cm2. Do any of these two measures help me to be 100cm2 step? And if so, what size hole should I make in the wall for each grid? My idea is to buy 15x15 grids of 100cm2 and I already started to make a hole in the wall of 10cm by 10cm. Is this correct? Thank you