Engine (5), Squad (3), and Traffic 33 responded to a reported House Fire in the 31-01 Box. Truck 31 arrived first reporting normal conditions from the exterior as the Police were reporting the fire possibly out. E33 arrived and sent its crew to investigate with C231 taking interior. C33 took the ventilation group on division 2. Crews confirmed the fire was out, reduced the box, and were on scene extended time for ventilation. Fortunately the residents had working fire extinguishers and used them before evacuating the residence.