LED high bay upgrade costs and savings: a UK guide for warehouses

Published 2026-10-26

Replacing metal halide, sodium or fluorescent high bays with LED is one of the most common energy projects in UK warehouses. This guide shows how to work out what an upgrade could save, what drives the project cost and how to check the payback for your own building.

How the saving is calculated

The energy saving from an LED upgrade comes from three numbers:

1. The wattage difference per fitting. Old wattage minus new wattage. For discharge lamps, use the total circuit wattage including the control gear where you know it.
2. The number of fittings.
3. The hours the lights are on each year.

Energy saved (kWh a year) = fittings x watts saved x hours / 1,000. Multiply by your electricity unit rate for the cost saving, and by the UK government carbon factor for the CO2e saving.

A worked example (estimate)

The figures below are an illustrative estimate, not data for any real site. They use the same starting values as our LED savings calculator.

Result (estimate): 50 x 250 W x 4,380 h = 54,750 kWh a year, about £15,650 a year at 28.59 p/kWh and about 7.2 tonnes CO2e a year. Your own figures will differ with your tariff, hours and the fittings you have now.

Where else savings come from

• Controls. Presence and daylight sensors dim or switch fittings in empty aisles and near rooflights. PS-UFO-MAX takes a plug-in PIR and daylight sensor. In warehouses with quiet periods or night shifts, controls can add a meaningful share of the saving, but the amount depends entirely on how the building is used, so we measure it rather than assume it.
• Fewer lamp changes. LED high bays need far fewer lamp changes than discharge lamps, which reduces work at height. PS-UFO-MAX is rated L80B10 above 50,000 hours (TM-21).
• Right light, not more light. A design to BS EN 12464-1 lights each zone to the level it needs, so you are not paying to over-light bulk storage.

What drives the project cost

We do not publish prices, because the cost of an upgrade depends on the site. The main drivers are:

• the number and type of fittings, and whether a one-for-one swap meets the required lux levels or a new layout is better;
• mounting height and access (scissor lift, boom lift, working around racking);
• whether controls and sensors are included;
• out-of-hours or phased installation to keep the warehouse running;
• condition of existing wiring and supports.

A survey and lighting design gives you a fixed scope to price against. Enter your own quote in the calculator to see the simple payback.

Checking the payback

Simple payback in years = project cost / annual cost saving. Use the unit rate from your own bill rather than a national average, and remember that hours matter more than anything else: a site lit 24 hours a day saves twice as much as one lit 12 hours.

If your organisation qualifies for ESOS, a lighting upgrade is often a clear opportunity to include in your action plan. See our ESOS Phase 4 guide.

Get a figure for your building

Every Polaris product carries a 5-year warranty. See our warehouse lighting page, the PS-UFO-MAX and PS-CURVE high bays, or request a free lighting survey and lighting design plan.

Sources

• DESNZ: Gas and electricity prices in the non-domestic sector, Quarterly Energy Prices table 3.4.2, Q2 2026 (provisional), small band 20 to 499 MWh a year, including Climate Change Levy, excluding VAT.
• DESNZ: Greenhouse gas reporting: conversion factors 2026, Scope 2, UK electricity.
• BS EN 12464-1:2021, Light and lighting. Lighting of work places. Indoor work places.

Frequently asked questions