A regular light bulb uses 60 W of power. Higher-powered bulbs can use much more than that–well over 100 W–while compact fluorescent bulbs use much less (15 to 20 W) and LED bulbs use less still.
Operating a 60 W bulb for 17 hours uses about 1 kilowatt hour (1 kwh) of energy, which is about the same amount of energy that is in 9 tablespoons of peanut butter. (approx. ¼ of a 500 ml jar).
As shown in the table below, other common things in our homes use a lot more energy than a single light bulb. A computer uses the equivalent of three 60 w bulbs, a large TV uses twice that amount. A hair dryer or a small heater uses 25 times as much and a typical clothes dryer 83 times as much.
|
Regular light bulb |
60 watts |
|
|
Computer |
150 watts (~3 light bulbs) |
|
|
Large TV |
350 watts (~6 light bulbs) |
|
|
Hair dryer or small heating unit |
1500 watts (25 light bulbs) |
  |
|
Hot water heater |
4000 watts (66 light bulbs) |
 |
|
Clothes dryer |
5000 watts (83 light bulbs) |
 |
The energy use of vehicles is significantly greater than that used in our homes and offices,
An average-sized car being driven at 50 km/h in the city uses gas at a rate of about half a cup per minute (100 ml) or 1/3 of a teaspoon every second. But gas has a lot of chemical energy in it. In terms of the amount of energy used, this is equivalent to running about 969 60-watt light bulbs!
Because cars tend to be less fuel-efficient at higher speeds, driving at highway speed (say 100 km/h) uses considerably more than twice as much energy as driving at city speed.
|
Average-sized car |
58000 watts (969 light bulbs) |
|
Steven Earle
March 2006