A musty smell in a home is almost always a sign of too much moisture. It often shows up first in spare rooms, wardrobes, cupboards or behind furniture. The good news is that once you understand the causes you can normally fix it with a few simple changes.
What causes a musty smell
Musty odours come from tiny mould spores and bacteria that grow in damp, still air. Common problem spots include:
- Spare rooms that are rarely heated or aired.
- Wardrobes pushed tight against cold external walls.
- Cupboards under stairs or in corners.
- Rooms where laundry is dried regularly.
If the air feels heavy and fabrics take a long time to dry, humidity is probably too high.
Find the damp spots first
Start by walking through the house and noting where the smell is strongest. Check:
- Behind wardrobes and large furniture.
- Inside cupboards and under sinks.
- On window frames and around skirting boards.
Look for dark spots, flaking paint or patches that feel cold and slightly damp to the touch.
Quick steps to clear the smell
- Let fresh air in – open windows in problem rooms for ten to fifteen minutes each day.
- Pull furniture away from cold walls – even two or three centimetres improves airflow.
- Clean visible mould – use a suitable mould cleaner or diluted bleach on hard surfaces, following the safety instructions.
- Wash soft furnishings – curtains, cushion covers and throw blankets often hold odours.
Use a dehumidifier to keep smells away
Once you have aired and cleaned problem rooms, a dehumidifier helps stop the smell from returning by keeping humidity under control. Aim for around fifty percent relative humidity.
Place the unit in the smelliest room and run it for a few hours each day. Over a week or two the air should start to feel fresher and fabrics should dry more quickly.
If you want some reliable models that work well in typical UK homes, take a look at our page on the best dehumidifiers for UK homes.
When to keep investigating
If a musty smell keeps coming back in the same area even after cleaning and drying, there could be a deeper issue such as a leaking pipe, damaged guttering or rising damp. In that case it is worth asking a professional to take a closer look so the underlying cause can be fixed.