Much energy is needlessly wasted in buildings through poor design and maintenance of electrical services. The energy that is wasted is of the worst kind, namely expensive electrical energy, which can be up to five times as expensive as the unit cost of heat. Unfortunately, excessive electrical energy consumption is all too often overlooked by misguided building designers, who focus on thermal energy consumption, which is relatively inexpensive. It has been shown that in a typical ‘standard’ air conditioned office building in the UK, an average of £3.30 per m 2 (of floor area) per annum is spent running pumps and fans, and a further £2.97 per m 2 is spent on the lighting . This compares with an average of only £1.78 per m 2 spent on heating, and £1.71 per m 2 spent on cooling . These figures demonstrate that in the average office building much more money is spent on running fans, pumps and electric lighting than is spent on operating boilers or refrigeration plant. Yet there are a number of relatively simple technologies that can be applied to motor drives and luminaire installations to dramatically reduce energy costs. That energy costs in these areas can be greatly reduced is clear from the evidence of the UK office building study, which found that in good practice standard air conditioned office buildings, only £1.65 per m 2 per year is spent running the pumps and fans, and only £1.48 per m 2 is spent on the lighting . This equates in each case to energy cost reductions of about 50% when compared with typical air conditioned office buildings.