What are “energy vampires” or “phantom loads”? First, they are not the monsters hiding in the closet to drain your energy and make really cheesy movies. (Those are completely different ones that won’t be making an appearance in this blog.)

Energy vampires are devices that use electricity when you think they are off. They are the cell phone and iPod chargers that are left plugged in, the computer that is left in sleep mode all day, or the TV that comes on instantly when you press the button on the remote. Electronics like this never really turn off. There is always some power going to them. This allows things like clocks on DVD players to still function while off, or for the TV to come on instantly with a remote control. Phantom load accounts for 64 million megawatts (or 64,000,000,000 kilowatt hours) of power and $4 billion a year in the United States.

To find out how much that means for you, we’ll have to do some more math!

Texas Average cost of electricity – in Houston it goes from $0.10 to $0.18 per kilowatt hour. So that makes an average of $0.14 per kilowatt hour.

Here are the two bits of math to keep in mind while we figure out how much phantom load we use and how much it costs.

1 kilowatt = 1,000 watts

1 kilowatt hour = $0.14

So how much phantom load do you have?

A cell phone charger uses 0.5 watts when it is just sitting there without a cell plugged in. That adds up to 0.012 kilowatt hours per day or $0.0017. For an entire month it uses 0.36 kilowatt-hours or $0.05 per month. Yearly it uses 4.32 kilowatt hours per year or $.60 per year.

That doesn’t sound so bad. Lets keep going.

photo credit: William Hook

An LCD TV of greater then 40 inches uses about 3 watts of power when it appears to be off, so the TV consumes 0.003 kilowatts per hour at a cost of $0.0042 per hour. For a day it uses 0.72 kilowatt hours or $0.10 every day. Per month it uses 2.16 kilowatt hours or $0.30 per month. Yearly it uses 25.92 kilowatt hours or $3.63 per year.

A computer uses 4 watts when it is off, 17 watts when it is asleep or 68 watts when it is on.

If you turn your computer off it is still taking in 0.004 kilowatts or costing you $0.00056 per hour which turns into 0.096 kilowatt hours a day or $0.01 every day. Over a month it uses 2.88 kilowatts hours or costs $0.40. In a year it will use 34.56 kilowatt hours or $4.83.

When you put the computer to sleep (lullaby little technology, go to sleep…) it still draws around 0.017 kilowatts per hour or $0.00238 per hour. That is 0.408 kilowatt hours each day or $.06 per day. Monthly that works out to 12.24 kilowatt hours or costs $1.71 per month. For an entire year that adds up to 146.88 kilowatt hours or $20.56 for a year.

If you’re like me and you leave your computer on all the time, it uses 0.068 kilowatts per hour, costing$0.01 per hour. Over one day it uses 1.632 kilowatts hours or $0.23 per day. If I left the computer on for a month it would use 48.96 kilowatt hours and cost $6.85. If I left it on for a whole year it would use 587.52 kilowatt hours and cost me $82.25.

After writing this blog I now turn my home computer off when I come to work.

A DVD player uses 1 watt while turned off or 0.001 kilowatt per hour and cost $0.00014 per hour so the DVD player uses 0.024 kilowatt hours a day and cost $0.00336 each day. Over a month it would use 0.72 kilowatt hours and cost $.10. Each year it would use 8.64 kilowatt hours and cost $1.21.

A Playstation 3 uses 1.5 watts per hour when it is off, so that’s 0.0015 kilowatts per hour and $0.00021. Each day that’s 0.036 kilowatt hours or $0.0054. Over a month it uses 1.08 kilowatt hours and costs $.15 per month. Yearly it uses 12.96 kilowatt hours and cost $1.81 per year.

A coffee maker uses 1.14 watts per hour while it is off. (This would be a coffee maker with a clock in it, or maybe a clock with an alarm that can be set to make coffee at a certain time). So the coffee maker would use .00114 kilowatts per hour and cost $0.0001596. Every day it would use 0.02736 kilowatts hours costing $.003804. Over a month it would use 0.8208 kilowatts hours and cost $0.11. Over a year, that’s 9.8496 kilowatt hours and $1.37.

That may all be small change, but it can add up. If you have a coffee maker, two cell phone chargers, a Playstation 3, three computers, a DVD player, and a LCD TV, then you spend about $2 a month just having stuff plugged in. (Note: I have not factored in monitors for computers, printers, microwaves, refrigerators, etc.)

photo credit: edkohler

So watts the answer? Should everything be unplugged when you’re not using it? The answer to that is probably not. Some things like smoke or carbon monoxide detectors should be left plugged in. Most people won’t want to spend the time plugging in and unplugging the TV to save a few dollars. But if you have a second TV that is not used very often, then it could be unplugged. Or if you don’t want to spend the time unplugging each cell phone charger, you could put them all on one power strip and turn the power strip off when you’re not charging. Now you can even get power strips that turn themselves off when they’re not in use. Mostly, it’s just being aware of your power usage. If you know that, you can make informed decisions.