The fire occurred at a residence in the 500 block of White Cottage Road in unincorporated Napa County, according to Napa County Fire Marshal and Cal Fire Battalion Chief Pete Muñoa.
The home's only resident observed smoke coming out of the eaves of her home and called 911 just before noon, Muñoa said.
Units and 21 firefighters from Angwin, Las Posadas and St. Helena stations of the Napa County Fire Department and Cal Fire responded to the fire, which Muñoa said caused moderate damage to the single story structure.
He said the fire was reported contained at 12:30 p.m. but units remained at scene performing overhaul and salvage until 3:15 p.m.
The blaze is believed to have been started by an electrical malfunction which occurred in an outlet in the living room ceiling which started the fire in the attic, Muñoa said.
No injuries were reported, Muñoa added.
Damage is estimated at approximately $80,000 with a property save of over $200,000, he said.
The home cannot be occupied due to the damage, and Muñoa said the home's resident is being assisted by the Seventh Day Adventist Church at Pacific Union College.