A 20-kW electric heater is used to heat up a house with size measured 6 m x 8m x 10 m.The house is equipped with a 500-W TV set, a 25-W light bulb, and a 250-W workstation. Heat is losingthroughwindows at a rate of 500 kJ/min. Ona cold winter day, the temperature droppedto 10°C, owner switched on the TV, workstationand heater. Determine the time needed to increase the indoor temperature to 25°C.