減低1度室溫, 需用多少能源, 有沒有算式可以計算?

I presume you mean the energy needed to lower the indoor AIR temperature by 1'C.

In that case, take the density of air (at 20'C) be 1.205 kg/m^3 and the specific heat capacity of air (at 20'C) = 1.005 kJ/kg.K

Hence, mass of 1 m^3 of air = 1.205 kg
Heat required to lower the temperature of 1 m^3 of air by 1'C
= (1.205 x 1.005 x 1) kJ
= 1.211 kJ = 1,211 J

If the volume of the room be V m^3, the total energy required
= 1211V J

N.B. The above calculation only shows the minimum energy required to lower the room air temperature by 1'C. During the process, temperature of wall material of the room is also lowered, and there are also heat loss due to thermal conduction through the walls and ventilation. These factors need to be accounted for in a practical calculation.