Why opening your bathroom window after a shower does more harm than goodFollowing a hot shower, humidity levels in a bathroom can surge enormously, especially in compact or poorly ventilated spaces. Opening a window following a shower might appear beneficial, but it can actually disrupt the circulation generated by extractor fans and bring in chilly air that speeds up condensation formation. "We recommend closing the shower screen or door, keeping towels and surfaces dry, and running the extractor fan with the door closed. Meanwhile, Nicholas Auckland, home heating and energy expert at Trade Radiators , suggests also wiping down all surfaces after a shower. "This makes it harder for condensation to form in the first place, however you must still refrain from opening your window wide here as this will remove all the warm air instantly".