Hello Herman,I'm living in the suburb of Brussel and yes,sometimes,it's more complicated than expected.I already had a simple ipcam 1mp,a chinese one and now I plan to install a network with 4 ipcam and a nvr.I'm here to try to make the right choice...
You need to compare apples to apples. You cannot compare an old pc with a new nvr. A modern efficient i5 haswell pc will consume about 30-40w with an average load.
Also is that 10w with the hard drive?
That's the problem. First generation i5. Video card if you have one adds lots of consumption. Inefficient power supply adds lots of consumption. A new pc will draw much less. With 4 x 3mp cameras you are looking at 25-30w or so.