What an office lighting specification contains
| Parameter | Typical requirement | Where it applies |
|---|---|---|
| Illuminance at the working plane | 300 – 500 lux | Open-plan desks |
| Illuminance, detailed work | 500 – 750 lux | Drawing, lab and inspection areas |
| Illuminance, circulation | 100 – 200 lux | Corridors and lift lobbies |
| Unified glare rating | UGR below 19 | Any screen-based workspace |
| Uniformity | 0.6 minimum across the task area | Open-plan floors |
| Colour temperature | 4,000K | General workplace |
| CRI | 80 minimum; 90 in design studios | All work areas |
Luminaire categories and Mumbai bands
| Luminaire | Where it is used | Band we observe |
|---|---|---|
| Recessed flat panel, 600 × 600 | Grid ceilings in open-plan offices | ₹1,100 – 3,800 |
| Linear suspended luminaire | Open floors with exposed services | ₹2,400 – 9,000 per metre |
| Recessed linear in gypsum | Design-led offices, reception | ₹2,000 – 7,500 per metre |
| Downlight, commercial grade | Cabins, meeting rooms, lobbies | ₹900 – 3,500 |
| Track and spot | Reception walls, artwork, retail | ₹1,400 – 6,500 |
| Industrial high bay | Warehouses, plant areas | ₹3,500 – 14,000 |
| Emergency and exit fittings | Escape routes, as per code | ₹1,200 – 5,000 |
Buying observations only, not official pricing. Project quantities on a commercial fit-out attract materially better rates than single-unit purchases.
Glare, screens and why UGR exists
A workplace lit to the right lux level can still be unpleasant if the fittings are bright in the field of view. Unified glare rating measures that, and in a modern office full of screens it is the number that determines whether people complain.
- Specify UGR below 19 for any area with screen-based work. For fine detail work the target tightens further.
- Low-UGR fittings use louvres, micro-prismatic diffusers or indirect distribution. They cost more than a bare panel and they are the difference between a comfortable floor and a headache.
- Indirect and semi-indirect luminaires light the ceiling and bounce the light down. They produce very low glare but need ceiling height and a light-coloured ceiling to work.
- Placement matters as much as fitting choice: a luminaire directly above and behind a monitor reflects in the screen regardless of its rating.
- Daylight is the best light in the building. Design the artificial scheme around the window zone rather than ignoring it, and zone the perimeter separately.
Controls, emergency lighting and landlord requirements
- Zone the lighting. A floor plate on one switch wastes energy and irritates everyone. Separate perimeter, core, meeting rooms and circulation.
- Occupancy sensing in meeting rooms and washrooms pays for itself quickly in a leased floor plate and is frequently required by the landlord’s fit-out manual.
- Daylight-linked dimming on the perimeter zone is worth specifying in a Mumbai building with large glazing.
- Emergency and exit lighting is a code requirement, not a design option. Confirm the requirement with the building’s consultant and the landlord early.
- Check the fit-out manual for restrictions on ceiling fixings, cable types and permitted luminaire classes before the scheme is drawn.
Retail and hospitality lighting, where the criteria change again
A shop is not an office. Where an office wants uniform, low-glare light, retail wants contrast: merchandise brighter than its surroundings, with high colour fidelity so a fabric or a finish reads truthfully.
- Accent-to-ambient contrast ratios of around 3:1 make displays read as displays. A uniformly lit shop looks like a stockroom.
- CRI above 90 for anything where colour is the product — clothing, paint, food, jewellery. Below that, merchandise looks tired under the light and customers notice without knowing why.
- Track systems give flexibility that recessed fittings cannot. Retail layouts change; the lighting has to follow without opening the ceiling.
- Beam angle is the retail specification most often ignored. A narrow beam on a display and a wide beam on circulation are different fittings, not different settings.
- Heat and running hours matter in a shop lit twelve hours a day. Check the fitting’s thermal design and driver rating, not just its output.
Our independence
Greenbox is an independent design and build studio. We hold no dealership, distributorship or channel arrangement with Wipro Lighting or with any other lighting manufacturer, and we take no brand-linked incentives. We specify against published photometric data, buy through Mumbai suppliers at market rates, and pass through invoices where we procure for a client.
Frequently asked questions
How much light does an office desk need?+
300–500 lux at the working plane for general screen-based work, rising to 500–750 for detailed tasks. Just as important is uniformity across the area — a target of 0.6 — because a bright pool beside a dim one is more tiring than a moderate, even level.
What is UGR and why does it matter?+
Unified glare rating measures how uncomfortable a luminaire is in the field of view. Below 19 is the usual target for offices with screens. Above it, people report eye strain and headaches without being able to name the cause, and the usual response — adding more light — makes it worse.
Is Greenbox a Wipro Lighting partner?+
No. We are independent and hold no dealership, distributorship or channel relationship with any lighting manufacturer. We specify against published photometric data and buy on the open market, passing through invoices where we procure.
Are occupancy sensors worth installing?+
In meeting rooms, washrooms and store areas, yes — those spaces are empty most of the day and the payback is short. On an open floor plate that is occupied continuously, the saving is smaller and daylight-linked dimming on the perimeter is the better investment.
Can I use domestic fittings in a small office?+
For a handful of cabins, sometimes. On any floor with screen-based work, domestic downlights rarely publish a glare rating and frequently perform poorly on it. Commercial luminaires cost more because they are engineered for a criterion that domestic fittings ignore.