every power supply is a converter it's never perfectly converting all the energy so some energy will be released in heat but the heat is not evenly distributed in your power supply but will be linked to specific components if the power supply is consigned in in the space where there's no air flow there's nothing the heat will raise the temperature of that part until an equilibrium is reached there's a rule of a thumb when you have a capacitor for every 10° you go down you double the lifetime let's say that the r temperature is 105° and they give you 5,000 hours you go to 95 it's 10,000 you go to 85 it's 20,000 you go to 75 it's 40,000 it makes huge difference whether you're at 77 or 87 or 97 degrees