A 4m x 5m x 3m room is heated by a fan coil that circulates hot water. The fan coil transfers 15,000 KJ/hr of energy to the room, while 5,000 kJ/hr is transferred from the room to the ambient. The fan power is about 200 Watts. If the room initial temperature is 5 C, 

calculate how long it will take to raise it to 25 C. 

Neglect the heat capacity of the walls. Take the air in the room as the system.