Every home told to stop opening bathroom windows after showers for important reason

It's a common habit to open a window after a shower to let out the steamy, humid air. Many homeowners believe it's an effective method to prevent mould growth in the bathroom, which is often the most affected room.

However, experts warn that this practice could actually be promoting mould growth rather than preventing it. In fact, it could be the reason why you're noticing black spores appearing in your bathroom.

Specialists at explain that opening the window post-shower, particularly when the outdoor air is colder than indoors, allows the cool outside air to mingle with the warm, moist air from the bathroom.This interaction causes water vapour to condense rapidly on surfaces, creating an ideal environment for mould to thrive.

The World Health Organisation (WHO) cites persistent dampness as the primary factor in mould development, making the bathroom a prime location, reports the It's estimated that the chance of finding mould in a bathroom is 2 to 3 times higher than in bedrooms or living rooms.

Following a hot shower, humidity levels in a bathroom can surge by up to 90%, especially in small or poorly ventilated spaces. This moisture adheres to tiles, mirrors, ceilings, and windows, and if not properly managed, mould can start to grow within 24 to 48 hours.

You might think cracking open a window post-shower aids in reducing steam, yet it can actually hinder the efficiency of extractor fans and let cold air in which speeds up condensation formation. This excess moisture is exactly what mould needs to flourish.

Sam Tamlyn, Managing Director at Shutter Store, remarked: "Opening the bathroom window after a shower can reduce the effectiveness of your extractor fan and create cross-drafts that spread moisture. Instead, focus on wiping down surfaces and letting your fan do its job. Understanding how ventilation works is key to keeping mould at bay."

To combat mould, experts suggest these alternative strategies to unwisely opening the window:

Slather mirrors with shaving foam

A novel approach involves applying a thin layer of shaving foam on your mirror, then buffing it with a towel or microfibre cloth to create a protective shield against steam. This nifty trick can maintain a fog-free reflection for weeks on end.

Install underfloor heating

Chilled surfaces like tile flooring are hotspots for sweat-inducing condensation. Warm, humid air solidifies into droplets once it encounters cold floors, fostering a soggy setting. Maintaining ground warmth above dew point level is crucial to dodge condensation.

Mop up excess water post-shower

Post-shower humidity has a penchant for clinging to any spot it can find - walls, mirrors, windows and even overhead. If left unchecked, this moisture can encourage mould growth. To avoid this, utilise a towel or squeegee to wipe down tiles, glass, and countertops, paying particular attention to corners and grout lines where mould is prone to accumulate.

Switch on the extractor fan

Extractor fans are engineered to expel damp air from the bathroom and vent it outdoors. Activate the fan prior to starting your shower and allow it to run for at least 30 minutes post-shower. It's also crucial to clean the fan every few months to eliminate dust and lint accumulation.

Employ moisture absorbers

Moisture absorbers such as silica gel, calcium chloride crystals, or desiccant containers are passive devices that extract surplus humidity from the air. They prove particularly beneficial in smaller bathrooms lacking windows or with inadequate ventilation.