---
title: "Xingguang | 40W Panel Lights | LED Lighting"
description: "A 40 W panel covers roughly 9–12 m² at 400 lx under a 3 m ceiling. In offices and clinics the binding constraint is glare, not wattage: at the same power, UGR<19 and UGR<22 are two price levels, and getting it wrong shows up as complaints about glare rather than on a lux meter."
url: "https://www.xingguanglightingcn.com/en/spec/panel-light-40w"
lang: "en"
updated: "2026-10-28"
markdown: "https://www.xingguanglightingcn.com/en/spec/panel-light-40w.md"
---

[Home](https://www.xingguanglightingcn.com/en/) / [Selection by specification](https://www.xingguanglightingcn.com/en/spec/) / 40W Panel Lights

# 40W Panel Lights

A 40 W panel covers roughly 9–12 m² at 400 lx under a 3 m ceiling. In offices and clinics the binding constraint is [glare](https://www.xingguanglightingcn.com/en/glossary#ugr), not wattage: at the same power, [UGR](https://www.xingguanglightingcn.com/en/glossary#ugr)<19 and UGR<22 are two price levels, and getting it wrong shows up as complaints about glare rather than on a [lux](https://www.xingguanglightingcn.com/en/glossary#illuminance) meter.

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## Key parameters

| Power | 40 W |
| --- | --- |
| Efficacy | 110 lm/W |
| Luminous flux | 4,400 lm |
| Maintained flux | 3,080 lm |
| Mounting height | 2.8–3.2 m |
| Coverage per fixture | 9–12 m² |
| Design illuminance | 300–500 lx |
| HID equivalent | 2 × 18 W |

[Product family: Panel Lights](https://www.xingguanglightingcn.com/en/product-categories/panel)

## What the wattage figure does not tell you

At 110 lm/W, 40 W gives about 4,400 lm at the fixture; applying a 0.7 maintenance factor, roughly 3,080 lm reaches the floor at end of life. Layout counts come from 3,080 lm, not from the nameplate 40 W — layout by wattage and the far row always ends up dim.

A second double count: the 110 lm/W figure already includes driver losses. Discounting again by driver efficiency deducts the same loss twice and over-counts fixtures.

## The height and area it actually covers

At 2.8–3.2 m and a design illuminance of 300–500 lx, one 40 W fixture covers about 9–12 m². That range is back-calculated from the maintained 3,080 lm, not the initial output — lay out on initial lumens and the site is under-lit well before the first relamping cycle.

If the existing HID is 2 × 18 W, 40 W lands in the same bracket: comparable flux, roughly a third of the power draw, and the circuit and switchgear usually carry over. What to re-check is inrush current and the earth-leakage setting.

## Four things to verify before ordering

① Whether flux and efficacy are quoted for the complete fixture or the light source — a 10–15% difference that changes the fixture count. ② Whether colour temperature and CRI are measured or nominal values; mixed CCT within one batch is the most common arrival dispute. ③ Driver brand and model, plus its derating curve at high temperature — it is the only part that really sets life. ④ The mounting kit list: chain, bracket and anchors in the box, or the site stops for a day.

## Concepts on this page

[Unified glare rating](https://www.xingguanglightingcn.com/en/glossary#ugr)[Illuminance](https://www.xingguanglightingcn.com/en/glossary#illuminance)[Colour rendering index](https://www.xingguanglightingcn.com/en/glossary#cri)

## Need a Lighting Plan?

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[All specification pages](https://www.xingguanglightingcn.com/en/spec/)