How to Get a Musty Smell Out of a Bedroom
A musty smell in a bedroom is almost always caused by one of two things: mould or mildew growing somewhere in the room (often hidden — in closets, under the bed, in the mattress, or behind furniture), or accumulated organic matter in soft furnishings that has become a source of bacterial activity. Here's how to systematically find the source and address it.
Step 1: Find the Source
Masking the smell without finding the source will always fail — the smell will return. Systematically check:
- Under the bed: Moisture can accumulate under low beds with restricted airflow. Check for dust, moisture, or visible mould.
- The mattress: Mattresses absorb sweat over time and can develop bacterial growth or mould inside. Smell the mattress directly — a strong musty odour from the mattress means it's the source.
- Closets: Closed closets with limited air circulation are prime mould environments, particularly in exterior corners and on the floor. Check corners, walls, and anything stored on the floor.
- Behind furniture on exterior walls: Furniture placed directly against an exterior wall can restrict airflow, causing condensation and mould on the wall behind it.
- Windows and window sill: Condensation on windows in cold weather creates a persistent moisture source — check the sill and wall below the window for mould.
Step 2: Address the Source
- Mould on walls: Clean with a bleach solution (1 cup bleach per gallon water), scrub, rinse, dry. Keep furniture away from the wall.
- Mattress odour: Sprinkle baking soda liberally on both sides, allow 24 hours, vacuum thoroughly. Repeat. For severe odour or visible mould, replace the mattress — mould inside a mattress cannot be remediated.
- Closet: Remove everything, clean all surfaces, treat visible mould with bleach solution, leave the door open to air out for several days. Store items off the floor to improve airflow.
Step 3: Increase Ventilation
- Open the bedroom window for 20 minutes daily to exchange stale humid air for fresh air
- Run a dehumidifier — target 40-50% relative humidity. Rooms where people sleep produce significant moisture from breathing and perspiration.
- Keep furniture 2 inches from exterior walls — this prevents condensation from accumulating on the wall behind the furniture
Step 4: Deep Clean Soft Furnishings
- Wash all bedding including pillows (most pillows are machine washable) in hot water
- Vacuum the mattress, box spring, and all upholstered surfaces thoroughly
- Wash curtains and anything stored in fabric bins or baskets
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