We follow 3 simple rules : 1) while I am away, I keep all my electrical items off. 2) I put my desk right angles to the window to make the best use of natural light and artificial lighting is partially avoided. 3) I am replacing all my bulbs (incandescent) lamps by low consumption ones. Namely: a) the mode of computers is economical, but still uses about 30% of energy, work better off the computer as much as possible. b) an ink-jet printer consumes 5 times less than a laser printer. c) for the reproduction of large quantities of documents, copies consumes less energy.