Sabina I am finding out right now just how powerful the smell is. My grow rooms are "rooms within room" in a far corner of my basement. They are nearly airtight, and I exhaust the inside air through a rather large carbon filter. During veg I hardly noticed anything, but I'm now in my 9th week of flowering, and the filter no longer can remove it all. My basement smells heavy and sweet, not exactly what you would think of as "weed", but definitely funky. I'm now noticing it about half way down the stairs to the basement. It's taking over! And just wait till it's all out of the grow room and hanging to dry! Lucky for me, my grow is legal, but if it wasn't I'd be very concerned.