We are about to get 4 to 5 inches of snow.Humidity in the room will be at an astounding high. I've found that moist,cold air from outside entering your grow space will raise the humidity from 40% to around 60% or more relative humidty.Thats not a good thing unless the room is full of cuttings. Mold grows at 60% humidity. Hydro systems suffer the most! I stick with soil grows.Alot more forgiving! There is a solution for this problem and it is to indroduce warmer intake air.Your central heating system can be used for this reduction.Use a wye to run a flex line from your intake to your ducting.Mix the air.Air circulation is vital.I would use this procedure in the winter only.In hotter months.Remove the conneted wye.You can handle the humidity better in the warmer months than colder.Just some food for thought!