Firefighters rushed out to reports of a loft blaze on Sunday night.
But when they arrived at Old Meadow Close, Berkhamsted, they realised it was a small fire in a first-floor airing cupboard, which was creating lots of smoke.
The firefighters from Berkhamsted and Hemel Hempstead made sure the flames did not spread and had put the fire out within an hour by 11.10pm.
Nobody was injured during the incident.