In my endeavour of building a low power computer I looked for a mean of measuring the power consumption of both my old and new systems. I came accross the Kill A Watt from P3 International. Most web pages about watt meters mentioned that home devices on "stand by", or even switched off, use a lot more electricity than one would think. So when my very own Kill-A-Watt arrived, I started measuring the power of every device I could get my hands on...
The numbers in the following table are Watts. I will update it as I find more time and devices.
| device | switched off | stand by | powered on | in use |
|---|---|---|---|---|
| TV Sony 27 inch trinitron | n/a | 4 | see "in use" | 75 - 110 |
| VCR AIWA multimode | n/a | 3 | 12 | 17 |
| DVD player Winstar 1200 | 0 | see "powered on" | 8 | 9 |
| VHF (antena) amplifier Electrohome | n/a | n/a | n/a | negligeable shows 0 watt |
| diode/laser printer Samsung QL 5100A | 0 | 10 | not printing not on standby just making noise: 12 | warming up or printing: 500 |
| 42 W fluorescent bulb Commercial Electric, 42 W | 0 | n/a | first 3 minutes: 39 | 32 |
| Video monitor (CRT) ViewSonic P815 (21 inch) | 0 | 119 | see "standby" | 125-140 |
| Video monitor (CRT) recent Dell (19 inch) | 0 | 1 | see "standby" | 44-52 |
| LCD monitor HP 1955 | 0 | 2 | see "standby" | 33 |
| cable modem Motorola CyberSURFR Wave Modem | 0 | n/a | 11 | 11 same regardless of the load |
| network switch Cisco Catalyst 2950 10/100 24 ports | n/a | n/a | 15 | 15 |
| network switch D-Link DGS 1008D Gigabit 8 ports | n/a | n/a | 5 | 5 |
| deskop PC Dell, P4 2.66 GHz, 1/2 GB ram | 2 | running screen saver 69 | idle 50 | 90 |
| deskop PC ASUS P2B, Pentium II, 350 MHz, 768 MB memory | 0.3 | n/a | idle running idle apache and postfix 53 | compiling a Linux kernel: 69 |
| desknote with LCD Elite Computer Group Desknote A900 | 0 | n/a | idle 18 | compiling a Linux kernel: 33 |
| Scanner Epson Perfection 1650 | n/a | 8 | n/a | 9-12 |
The price of electricity for residential use in Calgary on 23 May 2006 is 0.05594 CAD $/KWH. There are 8760 hours per year, which means that each watt costs 0.49 CAD $ per year for a device left on 24 x 7. One can draw a few interresting conclusions based on those numbers: