Energy efficiency It normally have an upfront cos...

Energy efficiency It normally have an upfront cost, which means there is a payback period involved. However, some low-cost measures achieve a payback of less than one year. Recommissioning is a good example, since it only involves skilled labor and the reconfiguration of existing components. In addition, energy efficiency brings a benefit that is not always considered: it reduces the load on electrical wiring. When energy efficiency is deployed in an existing building, the wiring ends up over-sized thanks to the reduced load. However, energy consultants do not recommend a circuit replacement in these cases: rewiring with smaller conductors has a cost, while leaving the existing circuits is free. The outlook is different in a new construction, since circuit capacities can be optimized before starting the project. Wiring Size Reduction Example: LED Lighting As an example, assume a distribution center uses 500 metal halide fixtures that consume 440W each. When all the lights are on, the total power consumption is 220 kW. With a 220V power supply, this results in 1000A in a single-phase installation, and 577A in a three-phase installation. Consider the effect of replacing all these fixtures with an equivalent LED product that consumes 150W: The total power consumption is reduced to 75 kW. The total current is reduced to 341A for a single-phase installation, and 197A for a three-phase installation (assuming 220 V in both cases).