How much energy & money do LED lamps save?

Grade level: 4th – 5th grades

Skills: Multiplication

Related environmental issues: Energy conservation

The table below shows how much electricity each light bulb uses to light your room in 1 year.

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  1. Your house has 30 light fixtures.  How much electricity do you use during a year if you use a regular light bulb for each light fixture?
  2. How much electricity do you use during a year if you use an energy saving light bulb for each house’s light fixture?
  3. How much electricity can you save if you replace all of the 30 regular light bulbs with energy saving light bulbs?
  4. The average price of 1kwh-electricity in California was 21 cents in August 2018. How much money could your family save for electricity in a year if you replaced all of the 30 light bulbs with energy saving light bulbs in a year?

 

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Answer keys

  1. 200 x 30 = 6,000 (kWh)
  2. 30 x 30 = 900 (kWh)
  3. 6,000 – 900 = 5,100 (kWh)
  4. 5,100 x 21 = 107,100 (cents) = $ 1,071