Firefighters say a man, woman and girl were lucky to escape after a fire broke out in a house in Wolverton early on Sunday morning.
Two crews from Great Holm were called to an end-of-terrace property in Church Street shortly before 6am.
The fire, which was caused by a coat left on top of a storage heater in the living room, spread to a sofa.
Crew manager Chris Bamford, who was in charge of the incident, said: “There were no smoke alarms in the house, so it was by sheer luck that the man woke up and managed to get them all out.
“It is essential to have working smoke alarms in your home. In many cases – particularly if a fire breaks out in the night – they provide the only warning the occupants will receive.”
Firefighters carried out a safety check after clearing away the smoke, and fitted three smoke alarms.
Mr Bamford urged anyone who does not have smoke alarms, or who has not recently checked that their smoke alarms work, to act now.