Hey guys

Just checking some numbers to work out how much a RasbPi costs per year in electricity. I'm basically looking for the worst case scenario (most expensive electricity tariff, 100% usage, 24/7/365) to check that I'm okay with running 1 (or more) RasbPi's.

So my maths is thus:

[*]RasbPi uses 5W maximum (5Vx1A=5W, although in theory it shouldn't go higher than 700mA and therefore 3.5W, I'm looking for worst-case and I've read that the Pi will shut down at 1A)

[*]At this rate it would take 200 hours to use 1kWh (1000Wh/5W = 200h)

[*]There are 8766 hours in most years, 8790 in a leap year

[*]Therefore the RasbPi, at this loading, would use 43.95 kWh per year (8790h/200hours per kilowatt hour)

[*]The most expensive energy tariff in the UK I can find is just under £0.20 per kWh

[*]Therefore the maximum theoretical amount a RasbPi should ever cost in a year is (43.95kWh*£0.2) which is £8.79

Or with more conservative estimates using the same maths

[*]At 3.5W maximum

[*]285.71 hours to use 1kWh

[*]30.77 units per year

[*]13.2 pence per unit (direct debit nationwide average feb 2012)

[*]£4.06 per year running costs

That's an absolute bargain either way you look at it, but I just wanted to check I'm not doing anything daft or missing anything obvious with these numbers?