I'm planning to build a NAS using an old computer case that is still very good and buying all other items like motherboard, cpu, hard drives, etc.; however, I want to plan the power supply to be efficient. How do I tally all the power demands from each component in order to keep the power demand to an absolute minimum - preferably to that of a laptop.
I plan to use this NAS not only as storage, but also as a media server, a website server, an email server and a VPN. If I need to use SSDs to keep the power demand down, I'll consider that too. However, how do I find the power demand for each component in order to choose a power supply that is not an over kill? I need to have power efficiency, because the NAS will be powered on continuously.