When you plug in some electronic products, transformers, and some non-Energy Star compliant devices (some of which still drain some electricity even when off), it runs continuously even if they are turned "off," though not as much, but a 15 watt transformer powering a radio or something 24 hours a day, seven days a week, & 365 days a year still consumes 15 watts even if the devices are turned off.
What I did was to buy power strips, or better, surge protector strips, as well as some small 1 1/2 by 1 1/2 on/off outlet switches that you place between the plug and the power outlet. Just turn on the power stips and outlet switches if you want to turn on your TV, stereo deck, amplifier, radio, DVD and Blu-ray disc players, and fans. When you're finished, turn the devices off, AND, turn off the power strips and outlet switches when you are not using them.
Here's the formula I developed to calculate how much something would cost for a day, month, and year. Just put in the wattage and rate per kilowatt (1/1000th of a watt) into the formula.
W = watts rated
C = rate per kilowatt hour
1. Cost Per Hour: W x C x 0.001
2. Cost Per Day: W x C x 0.024
3. Cost Per Month (365/12): W x C x 0.73
4. Cost Per Year: W x C x 8.76
Example: for a 10 watt device using electricity that costs 0.20 (20 cents) per kilowatt hour:
1. Cost Per Hour: 10 x 0.20 x 0.001 = $0.002
2. Cost Per Day: 10 x 0.20 x 0.024 = $0.048
3. Cost Per Month (365/12): 10 x 0.20 x 0.73 = $1.46
4. Cost Per Year: 10 x 0.20 x 8.76 = $17.52
So a 15 watt device can consume $17.52 a year based on the rate of 20 cents per kilowatt hour. 15 watts may be low, but $17.52 can buy you half a dozen home made meals!
1 kilowatt = 1000 watts
1 megawatt = 1000 kilowatts = 1,000,000 watts
Check out the pages to your left. Select a rate and see the tables to compare costs of running devices.