UFO High Bay Lights: 100W, 150W or 200W – Which Fits Your Ceiling Height?

Factory UFO lights (also called round high bays) are the most widely used fixtures in high-ceiling production workshops, warehouses, supermarkets and sports halls. The question customers most often ask dealers is whether to choose 100W, 150W or 200W, and how many units they need. Too few and the workshop is dark and workers suffer eye strain; too many and money is wasted on equipment and electricity. This article gives a quick selection method dealers can apply right away when advising customers.

What is a UFO high bay light, and when should you use one?

A UFO light has a round body with a large heat sink on top and hangs from a hook or chain. Its advantages are a compact build, good heat dissipation, quick installation and light focused down onto the floor. This type is suitable when:

• Ceilings from about 5 m and higher
• Large open spaces, few partitions
• Need to replace old high-pressure and metal halide lamps to save energy

For factories with long, narrow rows of racks, consider adding linear industrial lights so the light runs along the aisles.

Choosing Wattage by Mounting Height

The table below gives reference levels for typical production workshops using lights with an efficacy of about 130 lm/W:

• 4–6 m high: 100W, 4–5 m spacing between fixtures
• 6–9 m high: 150W, 5–6 m spacing
• 9–12 m high: 200W, 6–7 m spacing
• Above 12 m: 200W or more, preferably with a narrow 60° beam so light reaches the floor

This is a starting point. The final result also depends on wall and floor colors, the illuminance the work requires, and the machinery layout.

Quick Formula for the Number of Lights

Dealers can estimate using this formula:

Number of lights = (Target illuminance × Area) ÷ (Luminous flux per light × Utilization factor × Maintenance factor)

Here, the utilization factor is usually taken as about 0.6 and the maintenance factor about 0.8 for a clean factory.

Example: a 1,000 m² factory needing 300 lux, using 150W lights with 130 lm/W efficacy, i.e. about 19,500 lumens per light.

Number of lights = (300 × 1,000) ÷ (19,500 × 0.6 × 0.8) ≈ 32 lights.

You can quickly use the lighting estimate tool on our website to get a reference figure before sending a detailed quote request.

Reference illuminance levels for each area

• Storage warehouses, aisles: about 100–200 lux
• General production workshops: about 300 lux
• Assembly and fine-detail inspection workshops: 500 lux or more
• Indoor parking: about 75–100 lux

60°, 90° or 120° Beam Angle?

• 60°: focused light, for very high ceilings or for lighting deep down between tall racks.
• 90°: balanced, suits most factories 6–10 m high.
• 120°: wide light spread, suits lower ceilings and reduces dark spots between fixtures.

Consider the working environment

Workshops with heavy dust, humidity or high temperatures (textile mills, food processing, metalworking) should use lights rated IP65 or higher, with die-cast aluminum housings and quality drivers. In hot environments, fin-heatsink industrial lights offer a large heat-dissipation area that helps them last longer. For projects that need competitive pricing and large quantities, the Diamond UFO High Bay (Project Grade) is a choice many contractors use.

Conclusion

Choosing UFO high bay lights with the right wattage saves customers both investment and electricity costs, while helping dealers build credibility with contractors. Once you have the drawings or dimensions of the factory, send them to us for a free calculation of the number of lights, the layout and a detailed quotation.