right. i've finally managed to get hold of one of those meter things.
it's a "PM-230 electricity meter" like this
http://www.taperecorder.co.uk/energy.htmi've also calculated the cost of running a few devices. this is what i did if you wish to follow along...
used UKPower Cost Calculator
http://www.ukpower.c...nning-costs-elec.aspchecked that 10 pence seemed like a reasonable cost for kWh by looking at a pdf file i can't find the link for now - it was for prices starting march 2007 so it looked okay to me.
i used the pm-230 meter gadget to give me the
wattage readings for the devices i plugged into it. i didn't bother messing around putting the costs of electric into the device as it was too much for me to read the instructions.
after taking the wattage reading i put that directly into the UKPower cost calculator where it says "(Start from here if Wattage known)" and then i put the hours of use in to the month field. BUT i've ignored the monthly method and just calculated for 24 hours constant use a day, i.e. i put 24 into 'average hours used a month' field and accepted the final result as representing a single day - not a month. (i appreciate you could do a lot of this in your head as the calculations use multiples of 10 but i don't trust my mental arithmetic.)
here are my results:
all costs are for running devices for 24 hours at 10 pence per kWh
main pc setup =
£0.54 (i.e. 54 pence to run for 24 hours)
adsl wifi router
24" LCD monitor
amd 4800 dual core cpu, 4 hard drives, geforce 7800, audigy x-fi, 600w psu, several fans
creative 5.1 speakers
without the monitor on at all =
£0.40interestingly, if the monitor and speakers were OFF but remained connected to the mains electric supply they consumed about 4 watts (this wastage gets even worse for other devices as you will see below).
old pc =
£0.52amd athlon 2200, 1 hard drive, non 3d graphics, standard sound card
19" CRT monitor
without monitor on at all =
£0.29and, oh dear, with both pc and monitor OFF but still plugged in at the wall they consumed 46 watts, i.e. £0.11 a day just for doing absolutely nothing at all!!! (the pc used 31 watts when 'OFF' and the monitor 14 watts when off. that's without any LEDs flashing or any indication of the devices being on at all.)
pentium 4 laptop =
£0.17with wifi and 128meg 3d graphics
pentium 2 laptop =
£0.06with wifi card
old apple ibook g4 =
£0.08plugged in but turned off =
£0.02here are a couple of other things
32" widescreen CRT TV =
£0.31on standby = £0.02
14" portable CRT TV =
£0.12i hope that gives you some idea of the price. you can, of course, divide my results by 24 to get the hourly cost.
i think the most interesting thing is the power consumed by devices that are 'OFF'. i know we've been told in the UK to not leave things on standby but i was surprised to see just how bad my old pc and CRT monitor are at wasting energy when they are meant to be off - this is not even standby.
also i think it interesting that my newer pc with 4 hard drives, big 3d card and stuff consumes little more energy than my old amd 2200 machine with hardly anything in it. i know my 600watt psu is meant to be very good at not wasting energy (i.e. heat waste or whatever you want to define it as) but i'm still surprised by the comparison. i guess if i started heavy cpu tasks the power consumption would go up - i should have tested it.
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