[填空题]
An electric heater isnyan me x. m xd5)(ss(nnrwe;ak z37 8ra)8ec0 used to heat a room of vo*xho+m,yj ,sllume $62\,m^3$ Air is brought into the room at 5$^{\circ}\,C$ and is completely replaced twice per hour. Heat loss through the walls amounts to approximately $850 kcal/h$. If the air is to be maintained at 20$^{\circ}\,C$, what minimum wattage must the heater have? (The specific heat of air is about $0.17 kcal/kg\cdot C?$) W
