The fire started around 3 a.m. Friday morning at 319 Johnston Street in Rockford.
Rockford fire fighters say a pan of grease on the stove ignited. When fire fighters arrived, the first floor was completely engulfed.
The man who lived in the home was asleep. He and his dog were able to get out safely. Damage is estimated at $40,000.
Fire fighters say there were no working smoke detectors in the home.