Diagnose bad smells in your home
Smells are clues. Locate the source room-by-room, then match it to the most likely cause.
Musty room
Humidity or hidden moisture
Sour AC smell
Coil biofilm or drain pan
Bathroom smells after rain
Vent stack or drain trap
Laundry room smells
Drain trap or front-loader gasket
House smells stale
Ventilation and filter
Pet smell
Carpet, upholstery, HVAC
Frequently asked questions
What causes a musty smell in one room?
Usually trapped moisture: a leaky window, damp carpet pad, or poor ventilation pushing humidity above 60%. A hygrometer and a 24-hour fan test can confirm.
Why does my AC smell sour when it turns on?
Microbial growth on the evaporator coil or in the drain pan. A coil cleaning and clearing the condensate line usually solves it.
How do I get rid of pet smell in carpet?
Enzyme cleaners break down odor compounds at the source. Surface deodorizers only mask the smell temporarily.