light output and an increase in lifetime, as the previous extracts from the Electricians Guide illustrate. Since the decrease in light output will exceed the decrease in power drawn, the energy efficiency - luminous efficacy - of the lighting will drop. However, other types of lighting can also benefit from improved power quality, including systems with resistive or reactive ballasts. Fluorescent & discharge lighting is more efficient than incandescent lighting. Fluorescent lighting with conventional magnetic ballasts will see a reduced power consumption, but also a reduced lumen output from the lamp. Fluorescent lamps on modern electronic ballasts will use approximately the same power and give the same light. To provide the same wattage at the reduced voltage will require a greater current and increase cable losses. However, lighting controllers and ballasts are responsible for generating high levels of harmonic distortion, which can be filtered with some types of voltage optimiser, in addition reducing the need for lighting controllers. A common concern is that some lighting will fail to strike at lower voltages. However, this should not occur since the aim of voltage optimisation is not simply to reduce the voltage as far as possible, but to bring it to the service level voltage at which it was designed to operate most efficiently. Heating Heaters will consume less power, but give less heat. Thermostatically controlled space or water heaters will consume less power while running, but will have to run for longer in each hour to produce the required output, resulting in no saving. Switched mode power supplies Switched mode power supplies will use the same power as before, but will draw a slightly greater current to achieve this, with slightly increased cable losses, and slight risk of the increased current tripping MCBs. Energy savings The energy savings achieved by Voltage Optimization are an aggregation of the improved efficiency of all equipment across a site in response to the improvements in the power quality problems outlined above. It possible technique for savings in energy consumption in certain circumstances. Research in Taiwan suggested that, for an industrial supply, for voltage reduction upstream of the transformer, there is a 0.241% decrease of energy consumption when the voltage is decreased by 1%, and an increase of 0.297% when the voltage is increased by 1%. This assumed a mixture of loads including 7% fluorescent lighting, 0.5% incandescent lighting, 12.5% three phase air conditioners, 5% motors,