[填空题]
An electric heater i sh/0ypv 4am70ke*mups used to h pj 2*+)e .x)wcrv+ex0c/ttspj(llc n eat a room of volume $62\,m^3$ 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
