Sixteen floodlights, and the part nobody quotes for

The lamps were the easy bit. The tower access, the glare and the standard were the job.

Cheltenham Recreation Club was paying to run metal halide across four tennis courts, and replacing lamps regularly. Each failure was a tower access job before it was a lamp job, which is the cost that never appears on the quote.

Sixteen 450 W LED floodlights took the place of sixteen 1,500 W ones. Under a third of the power, and an estimated 70 per cent energy saving, or 30.66 MWh each year. Return on investment came in at 3.21 years.

The interesting part was not the wattage. It was the optics. Light that spills is light you paid to generate and then gave to the neighbours, so the replacements use optics that lay the light evenly across the court and a glare shield that keeps it out of surrounding windows.

It was surveyed after dark against Australian Standard 2560. That is the step that separates a lighting upgrade from a lamp swap, and it is the reason the figures above are measurements rather than estimates from a catalogue.