Tuesday, March 16, 2010

Day 71: The Computer Corner

I had heard about the concept of "vampire power" a long time ago. I think the first mention of it came in the form of an email sent out by Elon University's energy expert, Paul Holt. Checking my archives, I found the following from him way back on 8/30/2008:
Have you ever wondered how much that appliance is costing me to run? Can I get a more efficient appliance and save enough energy to justify buying a new one? How can I identify the “vampire” loads in my house? That is, the power that an electronic device might use when it is not operational...

There are several types of simple plug-in monitoring devices that can help the homeowner with these questions and more. You can Google “residential plug-in monitors” and find several brands. I have attached a link to one that I have purchased. It is inexpensive ($24.95+tax+no shipping cost) and can answer these questions for you.


While I remembered the term "vampire power" from that email, I had completely forgotten (in my conscious mind) about the Kill-A-Watt meter. Somewhere deep in my brain, however, I must have remembered it because I bought that exact model a few months ago to run the Day 34 freezer experiment.

Today, I've hooked it up to the power strip in my computer corner to find out how much energy each item uses when it's on and when it's "off." The picture below shows my setup (click on it for details on each component):

Energy in the Computer Corner

Everything on: 104 Watts. Everything off: 14.5 Watts. That latter number is equivalent to running my stepdaughter's night light 24 hours a day, 7 days a week.

Looking at my electric bill from last month, I see that I was charged $48.35 for 458 kiloWatt-hours or $0.11 per kWh. If I assume 8,766 hours per year, this rate equals $0.93 per Watt-year. Since this is pretty close to $1, I'm going to adopt it as a new "rule of thumb."

Reducing "always on" energy use by
1 Watt saves $1 in 1 year.

This is a little depressing. I had already wired all of my computer components to a power strip that I would dutifully shut off and save money. At most, I would save $14.50 the whole year (or enough for three trips to Irazu Coffee.) This is a start, but there must be a way to make deeper cuts into the energy bill.

1 comment:

  1. I'm interested in the planet impact of the vampire power. Here in our corner of NC, if we are on the power grid, we are primarily getting our electricity from coal. How many pounds of coal does it take to power us? Vampire and non-vampire? Can you decipher the information on this page: http://www.newton.dep.anl.gov/askasci/phy00/phy00211.htm