How students can measure electrical energy consumption

An example of a lession plan for teachers:


Home electrical energy consumption


The purpose of the lesson is for students to become aware of

  • methods to measure electrical energy consumption,
  • amount of energy households consume
  • differences in consumption among households
  • consumption of different devices
  • effects of people's behavior on energy consumption


Students individually read about method of measuring consumption.

They measure consumption in heir homes during one day.

They discuss results in the classroom, and clarify all problems they encountered while measuring and open questions they have.

Than they perform exercises in the form of measurements and experiments.



Daily household consumption

  1. Measure daily EE consumption in your home, during one week.
  • Plot the graph.
  • Join data of all students in the class.
  • Plot the graph of all measurements.
  • Discuss results.
  1. Divide consumption by the number of people living in a household.
  • Join data of all students in the class.
  • Plot the graph of all measurements.
  • Discuss results.
  1. Measure the consumption during an evening on a typical workday in three usage scenarios:
  • with typical usage of lights
  • leaving lights turned on in all rooms during the whole evening
  • trying to use as little of lights as possible and as absolutely necessary during the whole evening

Calculate the price of energy in all three scenarios, for daily consumption, monthly and yearly.

Discuss results. Propose methods to save energy and cost.

  1. Make a table with all light bulbs in your home. Enter their energy consumption and light production data in the table. Add the price of the bulb.
  • In adjacent column place the ee consumption data for CFL and for LED bulbs. Add their prices, too.
  • Now, calculate the savings your household could make if all bulbs would be replaced with CFL. Repeat for LED.
  • Calculate how much would such replacements cost in both cases (CFL and LED).

After how much time would more efficient bulbls pay themselves off?

      Incandescent CFL LED
Room Lumens Used hrs/day Watt EUR Watt EUR Watt EUR
Kitchen table                
Kitchen sink                
Kitchen wall                
Living room wall                
Living room ceiling                

Now estimate how much time each of existing bulbs is actually used (turned on) on average every day.

Propose which bulbs should be replaced with CFL, which with LED and which should remain the same, so that the pay-off period is the shortest.