The average thermal conductivity of the walls (including windows) and roof of a house in the figure is 4.8 cross 10-4 kW/m·°C, and their average thickness is 23.0 cm. The house is heated with natural gas, with a heat of combustion (energy given off per cubic meter of gas burned) of 9300 kcal/m3. How many cubic meters of gas must be burned each day to maintain an inside temperature of 23.0°C if the outside temperature is 0.0°C? Disregard radiation and energy loss by heat through the ground.