Energy consumption ? how much energy does a 100w light bulb use in an hour?

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1 week ago

%26#039;If it is incandescent then about 4 times as much as a CFL with the same brightness%26#039; - simply not true i%26#039;m afraid.

Best Answer - Chosen by Voters

If it is incandescent then about 4 times as much as a CFL with the same brightness. 33% 3 Votes

Other Answers (4)

• Electricity use for billing purposes is measured in kilowatt hours. One %26#039;unit%26#039; is one kilowatt hour. A kilowatt is 1000 watts, so your 100 watt lightbulb would use 1/10 of a unit. My last electricity bill charged me 8.75p per unit (before VAT), so it would cost just under 1p to leave a 100w light on for 1 hour. 11% 1 Vote
• 1 watt = 1 joule/second
  
  so 60minutes*60seconds*100 watts =360000joules=360 kj of energy? 22% 2 Votes
• 100 x 3,600 = 360,000 joules
  
  360 kJ = 1 kWh (kilowatt hour) 22% 2 Votes
• Absolutely 100 Wh 11% 1 Vote