Ask three contractors for a "lighting survey" and you may get three very different things: a set of lux readings, an energy audit with an LED payback calculation, or a full design review. The terms overlap, and buying the wrong one is the most common reason clients end up paying twice. This guide defines each term, shows what you should receive, and helps you match the survey to the question you actually need answered.
The short answer
| Term | Main question it answers | Core output | Typical trigger |
|---|---|---|---|
| Lux survey | Is there enough light, measured against the standard? | Measured lux grid, average, minimum and uniformity, pass/fail per area | Compliance, complaints, insurance, licensing, lease |
| Light level survey | The same as a lux survey | As above | As above |
| Lighting survey | Is the lighting fit for purpose overall? | Lux readings plus glare, colour, controls, condition and emergency lighting observations | Refurbishment, change of use, due diligence |
| Lighting audit | What does the lighting cost to run, and what could be saved? | Inventory of fittings, wattages, operating hours, energy use and upgrade options | Energy reduction, LED upgrade business case, ESOS or net zero reporting |
What is a lux survey?
A lux survey is a measured assessment of illuminance, the amount of light falling on a surface, expressed in lux. A trained surveyor uses a calibrated lux meter to take readings on a grid across each area at the correct reference plane. That is usually desk height for offices, floor level for corridors and the vertical face for warehouse racking. The results are compared with the relevant standard:
- BS EN 12464-1:2021 for indoor work places (offices, schools, warehouses, healthcare, retail);
- BS EN 12464-2:2024 for outdoor work places such as yards and external car parks;
- HSE HSG38 minimums for the legal baseline under regulation 8 of the Workplace Regulations 1992;
- BS EN 1838:2024 and BS 5266-1:2025 where emergency lighting levels are being checked.
A lux survey is objective and repeatable. It produces numbers that either meet the standard or do not, which is why insurers, inspectors and landlords ask for one. For the method itself, see what is lux testing.
Is a light level survey different?
No. "Light level survey", "light level testing", "illuminance survey" and "lux level survey" all describe the same measured exercise. The word "lux" is simply the unit. If a quote for a light level survey does not include measured readings against a named standard, it is not really a light level survey.
What is a lighting survey?
A lighting survey is a broader term. At minimum it should include measured lux levels, but it usually adds a qualitative assessment of the installation:
- glare from luminaires, windows and screens (relevant to display screen users);
- colour rendering and colour temperature consistency;
- visible flicker and failed or dimming lamps;
- condition, cleanliness and age of fittings;
- suitability of controls (presence detection, daylight dimming, zoning);
- observations on emergency lighting coverage.
Because the term is loose, always ask what is included. Some firms use "lighting survey" for a walk-round with no measurements at all. That may be useful for budgeting, but it gives you no evidence if compliance is challenged.
What is a lighting audit?
A lighting audit is primarily an energy and asset exercise. The auditor counts and identifies every fitting, records lamp types and wattages, estimates operating hours and calculates annual energy use and cost. The output is usually an upgrade proposal, for example replacing fluorescent fittings with LED and adding controls, with a payback period.
The risk with an audit on its own is that it says nothing about whether the new scheme will still deliver enough light. One-for-one LED swaps chosen on wattage alone regularly produce lower lux on the task, or worse uniformity. We cover this in can an LED upgrade reduce compliance. The best practice is to pair the audit with a lux survey before the upgrade (to set a baseline) and after it (to prove the result).
Which one do you need?
You need a lux survey if...
- an employee has complained about eyestrain, headaches or dark workstations;
- your insurer, landlord or tenant has asked for evidence of lighting compliance;
- you are applying for, or varying, a premises licence with lighting conditions;
- an HSE or local authority inspector has raised lighting;
- you need a lux check at the end of a lease for dilapidations;
- you have just completed an LED upgrade or fit-out and need sign-off.
You need a lighting survey if...
- you are planning a refurbishment or change of use and need to know what to keep;
- problems go beyond "too dark", such as glare on screens or poor colour in retail displays;
- you are buying or leasing a building and want a view on the condition of the installation.
You need a lighting audit if...
- your aim is cutting energy cost or carbon, or building a business case for LED;
- you need lighting data for energy reporting.
Most compliance-driven clients need a lux survey first. It is the fastest, most cost-effective option and the one that produces evidence. If the survey shows failures, the report's recommendations tell you whether you need cleaning, relamping, relocation or a redesign.
What does each cost?
Lux surveys are priced by area and building type. At Polarity Lux, a spot check starts from £90, an office or retail survey (single floor up to 250 m²) from £175, and a warehouse or industrial survey from £320. Wider lighting surveys and audits are quoted by scope because the inventory work scales with the number of fittings. See how much lux testing costs for what drives the price.
Book the right survey first time
If you are not sure which you need, tell us what prompted the question when you book. We will recommend the scope before confirming the price. Polarity Lux carries out measured lux surveys across London and the South East, from Kent and Surrey to Hertfordshire, Essex and Cambridgeshire. Book a lux survey.
Frequently asked questions
What is the difference between a lux survey and a lighting survey?
A lux survey measures illuminance with a calibrated meter and compares the results with a standard such as BS EN 12464-1:2021. A lighting survey is broader, usually adding glare, colour, condition and controls, and the term is sometimes used for unmeasured walk-rounds.
Is a light level survey the same as a lux survey?
Yes. Light level survey, lux survey, lux level survey and illuminance survey all describe the same measured assessment of how much light reaches each task area.
What is a lighting audit?
A lighting audit is an energy and asset review that records every fitting, its wattage and operating hours to calculate running costs and the savings from upgrades such as LED and controls. On its own, it does not prove compliance with light level standards.
Do I need a lux survey after an LED upgrade?
It is strongly recommended. One-for-one LED replacements can reduce light on the task or worsen uniformity, so a post-installation lux survey confirms the new scheme still meets BS EN 12464-1:2021.
Which survey will my insurer or landlord accept?
Insurers and landlords generally want measured evidence, which means a lux survey report showing readings, averages and uniformity against a named standard, signed and dated by the surveyor.