How to Choose LED High Bay Wattage for 6–14 m Warehouse Ceilings

"How many watts for my warehouse?" is the most common technical question in our inbox. Wattage is the wrong starting point — lux on the floor is the target, and watts are just one way to get there. But buyers need rules of thumb to shortlist models, so here is how our engineers size high bays before running the proper calculation.

Step 1: Start from the lux target, not the wattage

Light levels are specified in lux (lumens per square meter). Typical targets we design to:

Step 2: The mounting-height rule of thumb

With modern fixtures at 120–160 lm/W efficacy, these ranges land most projects close to target on the first pass:

For example, our High Bay runs 100/150/200 W at ≥110 lm/W, the UFO High Bay covers 80–240 W, and long narrow aisles often suit the Linear High Bay (50–250 W) better than round optics.

Step 3: Beam angle and spacing decide the rest

Two fixtures with identical wattage perform completely differently with different optics:

• 60° — tight cones for very high mounting (10 m+), concentrating light where racks are.
• 90° — the general-purpose choice for 8–12 m in open areas.
• 120° — wide, even coverage for lower ceilings (6–8 m) or racked aisles with reflective tops.

Spacing guideline: keep the mounting-height-to-spacing ratio near 1:1 to 1:1.2 to avoid dark lanes between fixtures, and stagger rows against rack directions.

Step 4: Stop guessing at tender stage — run the numbers

Rules of thumb get you a shortlist. For anything beyond a handful of fixtures, the correct tool is a photometric calculation in DIALux or Relux using IES/LDT files, which models your actual hall — ceiling height, rack layout, reflectances — and outputs average lux, uniformity (U₀) and glare values that a tender can be judged on.

Common mistakes we see in bids

• Comparing watts across suppliers. A 150 W fixture at 100 lm/W delivers less light than a 120 W fixture at 160 lm/W. Compare delivered lumens and ask for the LM-79 report.
• Ignoring uniformity. An average of 300 lux with dark patches at rack ends fails picking operations. Tender documents increasingly specify U₀ minimums.
• Overspecifying power "to be safe". Overlighting wastes capex and energy. Dimming drivers let you commission at full power and dial back after lux verification.
• Forgetting the environment. Dusty, hot or humid halls need the right IP and temperature range (our industrial ranges run −25°C to +50°C with 4–6 kV surge protection as standard).

Frequently asked

How many high bays do I need per 1,000 m²?

At 8–10 m mounting with 90° optics, roughly 16–25 fixtures at 150–200 W for 200–300 lux — but rack height and reflectances move this by ±30%. Run the calculation; it is free and fast.

UFO or linear high bay?

Round UFOs win in open halls and are easier to install point-by-point; linears win in narrow aisles and low-rack corridors where long distribution beats round cones. Both ship from the same QC lines.

Can I mix series in one warehouse?

Yes — mixed-SKU containers are standard practice. Many projects run UFOs over open areas and linears down aisles in a single shipment.