I was talking to someone who was considering using the VOIP (Voice Over IP) offered by their cable company. She was concerned about how much the modem would cost her to run. I came to realize that she was on a tight budget and was wondering how much it would add to her electric bill.
I didn’t know off hand how much power a modem draws so I started to think about a 100W bulb, and figured we can scale from there. If a bulb were left on 24/7, it would use about 72KWH of power in a month as there are 720 hours in a 30 day month. At her rate of 15 cent per KWH, this one 100W bulb would cost $10.80 to run full time each month. It turns out a modem is 10W or less, so it’ll take about $1/mo to run.
This exercise got me thinking. I bought a device a few months back to help me add up the current I use in my basement as I was wiring it room by room. It’s called Kill A Watt and available at Home Depot or on line.
The first thing I did was to find a power supply plugged into an outlet in my office with nothing attached. 4 watts! Now, I can afford the 40 cents per month, but how foolish is this, there’s nothing even plugged in, it powered a hard drive that’s now in a closet but I forgot to unplug the supply till now. Next, I checked how much power one of my old Macs was drawing. I was glad I use it remotely, no monitor, saving that power. But I found it uses 180W. About $19 per month. I need to rethink whether it’s worth it to keep this guy running.
Last, I’ve been replacing the incandescent bulbs with CFL (Compact Fluorescent Light bulb). Most rooms in our house have 4-6 in-ceiling cans that hold a 65W spotlight type bulb. The CFL replacement is 15W and puts out the same amount of light. So, anytime we are in a lit room, we’re saving 200W of power. Of course, during the day, it’s good to pull the shades/blinds and use natural light, but when we need to turn them on, it’s less power and less heat generated. How many power bricks do you have plugged in that are just keeping warm and burning your money? Have you gone to CFLs yet?