Household electrical energy consumption is typically studied in two categories: a) energy consumption for familiar end uses, and b) energy consumption for miscellaneous (other or residual) end use. Assignment of the different electrical energy uses to these two categories is not standardized, with different research groups using different assignments. Familiar end uses generally include space heating, air conditioning, water heating, refrigeration, cooking, clothes drying, dish washing, lighting, television, and furnace fans.

In the near future a large number of dwellings in Switzerland dating from the 50s to the 70s will need to be retrofitted in order to upgrade the comfort levels to today's standards and to reduce the energy consumption. By carrying out an overall retrofit of both the envelope of the building and the building services this can be successfully accomplished. Two retrofit projects of apartment blocks, one in Meilen and one in Cossau, demonstrate how a well-balanced strategy can achieve a comprehensive and economical retrofit.