Three Rural Fire Brigade appliances and one NSWFB appliance attended the fire at Grand Valley Circuit at Mullumbimby at about 12.30 am.
When firefighters arrived they found the occupants of the house had safely evacuated after smoke filled the house.
RFS Group Captain Michael Cooper said the smoke alarms saved the family by waking them from their sleep. By closing doors and windows as they evacuated, they helped to confine the fire to one room.
The residents had dialled 000 after they had all evacuated safely. Although the fire was confined to one room, firemen used breathing apparatus to help extinguish the fire as the house was filled with smoke.
RFS Community Safety Officer Laurence McCoy said people thinking they would be woken up by a fire was a myth.
He said the toxic smoke and gases were more likely to have the opposite effect.
The best way to protect your family was to have at least one working smoke alarm on each level of your house, he said.
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