How much energy does your home office actually consume? That’s what I tested with the help of a little gadget called the Kill-A-Watt. It’s a simple device that plugs into your wall outlet; plug your Mac and peripherals into it, and it’ll tell you how much electricity they’re pulling. So one Sunday, I plugged it in and then went about my usual business. You’ll see the results in the table below.
To give its readings some context, I then multiplied those energy readings by the numbers of hours in a year and the cost per kwh from my last electrical bill. The Mac mini, when in active use, consumes about 3 watts. Multiplying that by my cost per kilowatt hour and the hours in a year yields an overall cost of $25.20 per year.
That figure is, of course, inflated: It’s based on running the devices in “active” mode 24 hours per day, 365 days per year. So none of them reflect actual usage patterns; they’re for the sake of comparison only. Still, they should give you some idea about how energy-intensive your various peripherals and Macs can be.
Home Office Power Consumption
| Product | Watts Consumed | Cost per Year | |||
|---|---|---|---|---|---|
| Off | Sleep | In Use | In Use | ||
| Mac Mini/1.66 GHz | 1.0 | 2.0 | 29.7 | $25 | |
| Mac Pro/2.66GHz | 4.0 | 7.0 | 237.0 | $201 | |
| Power Mac G5/2.0GHz | 1.0 | 13.0 | 157.1 | $134 | |
| MacBook Pro 15-inch Core 2 Duo/2.16GHz | 1.0 | 2.0 | 23.5 | $20 | |
| PowerBook 12-inch G4/1.33GHz | 0.5 | 1.0 | 15.8 | $13 | |
| Brother laser printer | 0.0 | 8.0 | 750.0 | $637 | |
| Brother multifunction printer | 1.5 | 4.0 | 10.0 | $8 | |
| Canon Pixma ink-jet printer | 0.0 | 3.0 | 14.0 | $12 | |
| Apple 23-inch Cinema Display | 2.0 | 3.0 | 35.7 | $30 | |
| Sony 20-inch LCD | 0.0 | 3.0 | 33.0 | $28 | |
| Netgear Internet router | 0.0 | N/A | 3.2 | $3 | |
| Apple AirPort Extreme Base Station | N/A | N/A | 6.0 | $5 | |
| Netgear Fast Ethernet switch | N/A | N/A | 3.5 | $3 | |
| Yamaha speakers (desk) | 1.0 | 1.0 | 3.0 | $3 | |
| Yamaha speakers (subwoofer) | 2.0 | 2.0 | 6.0 | $5 | |
| LaCie 500GB Big Disk (over FireWire 800) | 0.0 | 19.0 | 22.0 | $19 | |
| Maxtor 200GB 5000DV (over FireWire 400) | 0.0 | 11.0 | 13.0 | $11 | |
| Epson Perfection 1660 scanner | 1.0 | 3.0 | 14.0 | $12 | |
| Desk lamp (compact fluorescent) | 0.0 | 0.0 | 22.0 | $19 | |
| Paper shredder | 0.0 | 3.5 | 134.0 | $114 | |
| Sony PlayStation 2 | 0.0 | 1.5 | 17.0 | $14 | |
| TOTALS | 17.0 | 90.0 | 1581.6 | $1,317 | |
N/A = not applicable. For “active” Mac tests, the Flurry screen saver (with default settings) ran for an hour or so. The paper-shredding test consisted of shredding one 8.5-by-11-inch page.The printing test consisted of printing one 8.5-by-11 page from a browser; the cost is based on a rough average of watts used to print. The hard-drive test consisted of copying a large file and noting the watts used; sleep means “not doing anything.”