The 25 x 10-metre house was fully alight when firefighters arrived.
Eight CFA fire trucks and firefighters from Koroit, Winslow, Kirkstall, Woodford, Warrnambool, Woolsthorpe and Toolong fire brigades responded to the incident. They were supported by CFA support vehicles and personnel and by FRV.
The fire is under control, but the house is extensively damaged.
The cause of the fire is unknown and will be investigated today.
A sole occupant of the house was able to self-evacuate and was attended to by Ambulance Victoria.
A stop was put on the incident at 7.38am.