Because of the laws of Thermodynamics*I don't know your equipment, but if you plug it into your wall outlet, it's most likely AC, unless it's running through some sort of power inverter. DC power is almost exclusive to battery powered equipment (in modern electrical systems that is). Here in the US we used DC power back in the days of Thomas Edison but that came to change when Nicola tesla proved AC was more stable, and safer in home use.
But because of the laws of that no dynamics heat is the natural byproduct of energy. There fore the more energy used, the more heat is produced in the process. That's why with light systems there is always some sort of heat control whether it be passive ( like the ones with aluminum heat sinks) or active ( the ones with built in fans). This is the case with all electrical components, I only use lights for the example because they are easy to reference.