Does this look odd to you, too? This is a picture of two exhaust fan pipes from two separate second floor bathrooms vented into – but not out of – the attic. Excessive moisture from these fans is constantly vented directly into the attic, which causes condensation on the wood sheathing of the roof, on insulation, and anything else that is kept in the attic. This excessive moisture has led to what appears to be mold growth on the wood sheathing. This growth will continue to spread and the wood will eventually deteriorate. This means a leaking roof in addition to the undesirable effects of mold and/or other organic growth that you most definitely do NOT want in your home. In a nutshell, ALWAYS VENT OUTSIDE. You will save yourself money and headaches (and undesirable living conditions) if you do!