Have you ever wondered how much a certain appliance contributes to your overall electric bill? Well, wonder no more. The Kill-A-Watt electric usage monitor is a nifty gadget which will help you determine just that.

This device utilizes an LCD display to show electricity consumption by the kilowatt-hour. Simply multiply the kilowatt-hours displayed by the price per kilowatt-hour on your bill to determine exactly how much that appliance is costing to run per month.

Other information is displayed as well. You can monitor the quality of your line power by displaying the voltage and line frequency. This way you can determine if bad line power is causing your appliance damage or causing it to run inefficiently.

As a real world example, consider the following: I run a small data center in my home. It is housed in a walk-in closet in my office. The constantly running equipment is listed below:

• Media server: P3 500 MHz, 750MB RAM, 320GB HDD, 300 watt power supply
• File server: 2 x 1GHz P3, 1GB RAM, 2 x 37GB HDDs, 500 watt power supply
• Phone server:P4 dual-core 2.4 GHz, 2GB RAM, 40GB HDD, 200 watt power supply
• HP rack-mount switch 16-port
• HP rack-mount hub 24-port
• Router
• 2 x USR external modems
• Cable modem

All together this setup draws about 252 Kwh per month (as determined by Kill-A-Watt.) Based on my power bill, I pay about $0.12 per Kwh (average including fuel & non-fuel charges.) So based on those numbers, my little closet data center costs me about $30 per month to run.

Based on this knowledge, I could design a small solar power system to run my computer systems. Upcoming project? Maybe! Stay tuned.

Kill-A-Watt also has a line of similar products with various form factors.

Filed under: Green Products