Hall County firefighters responded to a house fire at about 1:15 a.m. Tuesday in the 4000 block of Canberra Way in South Hall County.The 2,000-square-foot house was fully involved and is a total loss, Hall County Fire Marshal Capt. Scott Cagle said. Damage is estimated at $100,000.Neighbors said the house has been vacant more than a year, Cagle said.The cause of the fire is still under investigation.