LED vs Halogen Energy & Payback Calculator

Commercial LED retrofits typically pay back inside 18 to 36 months at current UK electricity rates, but the case only holds if you size the saving correctly. A 50 W halogen running 12 hours a day, replaced with a 7 W LED of equivalent output, saves around 188 kWh a year per fitting. Across a retail unit with 60 fittings, that is over 11 MWh a year, which at typical mid-market commercial rates is meaningful money before you factor in the avoided lamp replacements and maintenance access costs.

For a facilities or finance lead building the business case, the payback period is what unlocks capex sign-off, but the carbon line is what gives the project a second hearing. Each MWh of grid electricity avoided takes roughly 200 to 250 kgCO2e off the SECR scope 2 figure under the current UK grid carbon intensity. For an estate reporting under SECR or working toward a science-based target, a lighting refit is one of the cleanest interventions on the table, because the savings are real, the kWh is metered, and the carbon claim is defensible.

For hospitality and retail in particular, the operational case often beats the bare-bill case. Halogen lamps in display lighting fail on a 2,000 to 4,000 hour cycle. LED equivalents are rated for 25,000 hours and upward, which on a 12-hour daily duty is roughly six years between replacements. That removes a recurring service line, removes the ladder-and-access cost in trading hours, and removes the embodied carbon of the replacement lamps. None of which shows up in a simple kWh saving, but all of which lands on the operations P&L.