Consider two identical rooms one with an energy saving LED l

Consider two identical rooms, one with an energy saving LED light bulb of 30 watts in it and another one with an inefficient incandescent bulb of the same wattage. If all the doors and windows are closed, which room will be hotter after 5 hours and 32 seconds of operation starting from the same temperature of 70 Fahrenheit? Why?

Solution

30 Watt of incandescent bulb have bulb temperature of 100.5 F

30 watt of LED have temperature of 26.1 F

Q=mC_p(T₂-T₁)

where m is mass of air in the room

C_p specific heat at constant pressure of air

T₁ is room temperature

T₂ is room temperature

as m ,T₁ and C_p is same for both room heat transfer will only depends on temperature difference so the temperature difference of the room with incandescent bulb is more so regardless of the time of use the room with incandescent bulb will be hotter than the room with LED bulb