Dave,
My figure of 6.8 KWh means that over, say, an 8-hour working day it
consumes getting on for a kilowatt, but that's assuming 100% efficiency. So I
presume it uses rather more than this. Even so, that's only one bar of an
electric fire or a bit more. It would seem to be worth it if your office is
your livelihood.

Tudor Hughes, Warlingham, Surrey.