Day 4 – Home Energy Use – The Net Zero Energy Home

The Big Idea

Japanese houses do not have central heating and air conditioning. Still residential energy use has been hard to reduce.


  • Name two ways to stay comfortable in a house with no central heat. (Sitting at the kotatsu and soaking in a hot bath before bed.)
  • Identify ways that builders, encouraged by the government, can build zero net energy houses (ZEH.)



  1. View Youtube Video #9
  2. Tell the students that taking a hot bath at night and getting right into bed under heavy quilts is another way people stay comfortable in an unheated house. They do not leave a heater running at night. They just turn it on in the room they are using when they wake up in the morning.
  3. Remind them of Day 3’s lesson. Why don’t pipes freeze? How is the hot water in the kitchen, bathroom and laundry also saving energy?
  4. Examine the graphs and information on the METI Report , “Definition of ZEH…”
    • Answer the following questions:
    • Has household energy consumption risen or fallen over the last 40 years?
    • Have conservation measures since 2011 caused a drop in household energy use?
    • How has the amount of electricity used for different purposes in an average Japanese home changed over the years?
    • To bring down the amount of energy used in the residential sector, what does METI propose?
  5. View Youtube Video #10: Japan: Smart Green Homes on the Horizon