Lighting controls and your commercial EPC rating

Why controls are credited

The assessment does not just ask how much power your lighting draws. It asks whether the lighting is capable of drawing less when it does not need to be on. A fitting that dims when daylight floods the space, or switches off when a zone is empty, is modelled differently from an identical fitting on a single switch at the door.

That is a genuinely favourable quirk for a landlord. Controls are a modest capital item that affects an input the model treats seriously, and unlike fabric work they can go in without touching the structure.

The strategies, and where each one earns its money

• Occupancy or absence detection. Best in spaces used intermittently — stores, plant rooms, WCs, meeting rooms, warehouse aisles. Worst in a space that is continuously occupied, where it does nothing.
• Daylight dimming. Best where there is real daylight to harvest: rooflit warehouses, perimeter office zones, anything with significant glazing. Pointless in a windowless core.
• Zoning. Splitting a large floor so you are not lighting all of it for the two people working late. Cheap at first fix, awkward and expensive to retrofit afterwards.
• Time scheduling. Crude, cheap, and still the one that catches the most waste in retail and hospitality, where the real problem is lights left on after trading.

The mistake worth avoiding

Specifying controls for a space whose pattern of use does not suit them. Occupancy sensing in a continuously staffed production area adds cost, saves nothing, irritates the people working there, and gets disabled within a month — at which point you have paid for a measure that is no longer there when the building is reassessed.

Controls should be chosen zone by zone against how each space is actually used. A quote that applies one strategy across a whole building has not looked at the building.