Almost every high bay job comes down to two shapes. Round UFO high bays pack a lot of light into a compact puck. Linear high bays spread it out over a longer fixture. Both replace metal halide and fluorescent high bays, but they are not interchangeable on every ceiling.
The short version
| UFO high bay | Linear high bay | |
|---|---|---|
| Shape | Round, compact, heavy for its size | Long rectangular body, usually 2 ft or 4 ft |
| Light pattern | Concentrated, round footprint | Wider, more even spread along its length |
| Typical mounting height | Higher ceilings, often 20 ft and up | Lower to mid ceilings, often 12 to 25 ft |
| Best fit | Open warehouses, gyms, manufacturing | Aisles, retail, shops, lower bays, fluorescent replacements |
| Mounting | Hook, pendant or chain from one point | Chain, V hooks or surface mount |
| Glare | Bright point source, can be harsh at low heights | Lower brightness per square inch, easier on the eyes |
When a UFO high bay makes sense
A UFO high bay puts all of its LEDs on one round heat sink, so you get a lot of lumens from a small, single point fixture. That is exactly what a tall, open ceiling needs. The light has a long way to travel, and a concentrated beam gets it to the floor without wasting much on the walls.
UFOs are also the quickest install when you are swapping out round metal halide fixtures. Hang it from the existing hook or conduit, land three wires and move on. If you are replacing 400W metal halide, start with our 400W metal halide replacements and the metal halide to LED wattage chart.
- Ceilings roughly 20 ft and higher where you need punch at the floor.
- Open floor plans like warehouses without high racking, gyms and manufacturing floors.
- One for one metal halide swaps where the old fixture hung from a single point.
When a linear high bay makes sense
A linear high bay spreads the same kind of output over a longer body. The light comes out wider and softer, which gives you better uniformity and less glare at lower mounting heights. It also lines up naturally with racking, so the light lands down the aisle instead of on the top shelf.
Linear fixtures are the natural replacement for 4 lamp and 6 lamp T5HO and T8 fluorescent high bays. The footprint is similar, so the new layout usually follows the old one.
- Ceilings roughly 12 to 25 ft where a UFO would look like a hot spot.
- Racked aisles, especially with an aisle optic if one is offered.
- Retail, shops and work areas where people look up and glare matters.
- Replacing fluorescent high bays on the same chain hangers.
Rule of thumb: if people work under the fixture at a lower height and look up often, lean linear. If the ceiling is tall and open and you mainly need light on the floor, lean UFO.
Ceiling height and spacing
Mounting height drives both fixture choice and wattage. A common starting point is spacing fixtures roughly 1 to 1.5 times the mounting height apart, then adjusting for the target light level. Our guide on how many LED high bays a warehouse needs walks through the math, and the lighting layout calculator will give you a quick count. Check your target against the foot candle requirements by space type.
Features worth checking on either style
- Selectable wattage and CCT. Many high bays let you set the output and color in the field, so one SKU covers several jobs. See how selectable wattage and CCT works.
- 0-10V dimming for daylight harvesting and controls.
- Sensors. Plug in or integrated occupancy sensors make a big difference in warehouses with light traffic.
- DLC listing. If the customer wants a rebate, the exact model typically needs to be DLC listed.
- Wet or washdown areas. Use a vapor tight fixture instead of a standard high bay.
Not sure there is money on the table? Find out if there are rebates in your area before you price the job.
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