What kind of FV do you use Pavros?
I'm about to dry hop an American Amber / Red. I want to throw the pellets in loose to get maximum aroma, but I'm using simple plastic buckets and fermenting in a cupboard that holds a steady 20deg. I've always been fearful of cold crashing due to the thing contracting and pulling air through their airlock.
I use a normal plastic bucket with lid. I never use an airlock, just clip the lid on fully then loosen/lift up about 1/4 of the lid. That way, I don't have to worry about liquid in the airlock being sucked back in.
I use hop pellets and throw them loose into the fv when dry hopping. I've never had a problem in 70+ kits. I leave the fv on the garage floor overnight and all the hop detritus drops to the bottom. When siphoning to the bottling bucket for batch priming, I tie a small mesh bag (the ones from the Festival kits) to the end which stops most of the **** transferring.