In winter, when the outside temperature is \(0^{\circ} \mathrm{C}\), a room is to be maintained at \(25^{\circ} \mathrm{C}\). The heat loss from the room is estimated to be \(5 \mathrm{~kW}\). Two alternative strategies to keep the room temperature constant are:

(a) direct electrical heating and

(b) reversing the room air-conditioner. Which is the better proposition?