Probably a very stupid question but.....

If you look on the back of the electrical good, it will wtate that watts it comsumes

There is 1000watts in 1 kwh. T0 give you an idea, my 50inch rear projection tv consumes 210 watts per hour. Therefore i can have it on for approx 5 hours for it to use 1kwh costing me only a total 12-13 pence for 5 hours viewing

Also this, Sammy, you will need to know the wattage of the appliance and the price of each kwh as per your bills.

http://www.ukpower.co.uk/running-costs-elec.asp

rosscobley wrote:

I would say that a computer would be not far off 1kw per hour. The computer supply will be about 400w plus the Moniter is prob about 300-400w and maybe the printer and speckers so i would base a computer as 1kw per hour

I would say that it would be about one tenth of your figure! Something like 100 - 130W, certainly no where near 1kW. I keep meaning to measure my system with a power meter but have not got round to doing it yet. Modern monitors with LCD screens use less than the older CRT monitors and laptops probably only around 30W.

:rotfl:

rosscobley wrote:

Computer cpu's start from about 250w up to about 400w Plus you have to add things like a printer being on speckers being on maybe a wireless router, Mointer, ect ect all depends on what is connected.

This is an example of little knowledge on a subject being a dangerous thing! Your figures "250W up to about 400W" refer to the total output wattage of the computers power supply unit. As the output voltages are relatively low, 5V, 12V etc. the output wattage is totally different to the total input wattage used by the computer. i.e. at mains voltage and is dependant on the efficiency of the switched mode supply used.

My desktop system with LCD monitor, separate powered speakers, printer and including a PocketPC on charge is using 134W at the moment, measured on a power meter while typing this.

rosscobley wrote:

I would guess anywhere around 1/2 to 1kw per hour

No where near unless you disbelieve a digital power meter! You have however prompted me to measure the consumption of my system but I knew before due to electricity consumption that it could not be anywhere near your figures, as the PC is usually on for 8-10 hours per day and we simply do not use as much electricity as your figures would suggest.

:rotfl:

The 300W or 400W rating of the power supply unit (PSU) is the maximum it can deliver before it will overheat, not what it will normally use. My computer is now using 113W (plus 63W for the monitor). So I could use my computer for 1000/176 hours for 1kWh. i.e. over 5 hours. A less efficient computer and monitor could easily use 250W though. Many PSUs are only 75% efficient so use 160W to output 120W. I recently changed my PSU to a FSP Zen and saved 40W. HTH