Frequently asked questions

• What is an LED high bay light, and what makes it different from a regular light?

  High bay LED lights are powerful fixtures engineered specifically for spaces with ceilings 15 feet and higher. Unlike standard overhead lights, they produce a concentrated, high-lumen beam designed to travel far downward and maintain adequate foot-candle levels at floor level in tall spaces like warehouses, factories, gymnasiums, and distribution centers. GJIA high bays achieve 150 LM/W efficacy — meaning you get dramatically more light per watt than older metal halide, HPS, or fluorescent fixtures.

• What is the difference between the HB Series, the L2204 Adjustable Series, and the H2309 Linear Series?

  The HB Series (black or white housing) is a classic UFO round high bay available in 150W–300W, certified DLC/ETL and ideal for retrofit and new-build commercial/industrial facilities. The L2204 Adjustable Series covers a wider range — 100W to 400W — and carries the cETL mark, making it specifically recognized in both the US and Canada. The H2309 is a rectangular linear high bay (available in 2 ft and 4 ft lengths) with a 90° wide-angle prismatic diffuser, built-in PIR motion sensor, adjustable CCT (4000K/5000K), and 4-step wattage selection (100%/80%/60%/40%) — ideal for aisles, retail, and large open bays where glare control matters.

• What is a UFO high bay light? Why is it called 'UFO'?

  UFO high bay lights get their name from their round, disc-like shape — resembling a flying saucer. This compact circular form factor replaced the large bell-shaped metal halide fixtures that were standard in warehouses for decades. UFO designs concentrate a high-output LED module in a small, thermally efficient aluminum housing, delivering excellent lumen-per-watt performance while being easy to mount via a single hook or pendant.

• Which color housing should I choose — black or white?

  Both the black (HB Series) and white (HB White Series) are identical in all electrical and photometric specifications — same wattages, same lumen output, same certifications, same 5-year warranty. The choice is purely aesthetic. Black is the classic industrial choice for warehouses, factories, and manufacturing plants where the fixture will hang high and won't be prominently visible. White suits gymnasiums, auto dealerships, retail showrooms, commercial spaces, and any application where a cleaner, more finished look is preferred.

• What wattages are available, and how do I decide which one I need?

  GJIA offers UFO high bays from 100W (15,000 lm) up to 400W (60,000 lm). A rough selection guide by ceiling height: for 15–20 ft ceilings, 100W–150W is typically adequate; for 20–25 ft ceilings, 150W–200W; for 25–30 ft ceilings, 200W–240W; for 30–40 ft ceilings, 240W–300W; for ceilings above 40 ft or large open industrial spaces, the 300W–400W option ensures sufficient floor-level illuminance. Always verify with a photometric calculation or foot-candle target.

• How does the selectable wattage feature work, and do I need a special tool?

  All GJIA UFO high bays (except the 400W fixed model) include a wattage selector switch on the driver or housing, accessible before installation. You simply flip the switch to 100% (full wattage), 80%, or 60% of the rated wattage. No tools, no programming, no extra hardware required. For example, the 150W HB sets to 150W, 120W, or 90W at a flip. This is useful when you want to match light output to a specific foot-candle target or reduce energy costs during off-peak hours without installing a separate dimmer.

• What does 150 LPW (lumens per watt) mean, and why does it matter?

  150 LPW means the fixture produces 150 lumens of light for every watt of electricity consumed. A 200W GJIA high bay delivering 30,000 lumens at 150 LPW replaces a 750W–1,000W metal halide fixture producing similar light — an energy reduction of 70–80%. Over 12 hours per day at a US commercial rate of roughly $0.13/kWh, a single 200W LED unit saves approximately $215–$280 per year compared to a 1,000W metal halide.

• What is the main difference between a UFO high bay and a linear high bay?

  UFO fixtures emit light from a single circular point, producing a conical beam (typically 90°–120°) that concentrates high lumen output in a relatively small area — ideal for tall, open spaces. Linear fixtures are long rectangular forms with a 90° beam angle that distributes light in a wide, strip-like pattern along their length — ideal for aisles, shelving rows, retail displays, and any long, narrow space. If your layout resembles rows of racking, a linear high bay placed above each aisle will give you more uniform, targeted illumination than a UFO positioned between rows.

• Which type should I use for my warehouse?

  Use UFO high bays for: open floor areas (receiving floors, shipping areas, assembly zones), ceilings above 25–35 ft, or when replacing existing round metal halide fixtures one-for-one. Use linear high bays (H2309) for: aisle lighting between racking systems, supermarkets and retail floors, distribution center pick-and-pack areas, gymnasiums where uniform low-glare illumination is critical, and ceilings in the 15–25 ft range where the wider linear beam pattern provides more even coverage. A common approach for large warehouses is UFOs over open areas and linears over racking aisles.

• Can I use UFO high bays in a gymnasium or sports facility?

  Yes — UFO high bays are widely used in gymnasiums, especially for ceilings 20 ft and above. The IK08 impact rating on GJIA UFO fixtures means the lens can withstand a 5-joule mechanical impact (equivalent to a basketball or volleyball strike), making them suitable for court-level sports areas. For gymnasiums, many installers choose the white housing (HB White Series) for a cleaner look, and use the 0–10V dimming feature to reduce output during non-game hours.

• Why does the Linear H2309 have a prismatic diffuser while the UFO models don't?

  A prismatic diffuser breaks up and scatters light across a wider angle, dramatically reducing direct glare. This is especially valuable in environments where workers look up frequently (retail aisles, supermarkets, offices above pick lines) or where uniform vertical illuminance is needed (reading labels, scanning barcodes, inspecting merchandise). UFO fixtures are typically installed so high that direct glare is less of a concern; their lenses are optimized for light transmission efficiency rather than diffusion. If glare control is your priority at lower ceiling heights (15–25 ft), the H2309 linear with its prismatic diffuser is the better choice.

• What is the ceiling height range for each type?

  UFO high bays are designed for ceilings roughly 15–40+ ft, with most installations between 20 and 35 ft. Fixtures above 35 ft should use the 240W–400W range to deliver adequate floor-level foot-candles. Linear high bays like the H2309 perform best at 15–30 ft; their 90° beam angle and 4-step wattage selection make them versatile for mid-height ceilings, and their steel wire rope mount allows easy height adjustment.

• How are GJIA high bay lights mounted?

  UFO high bays include an eye-bolt (hook) at the top for chain, cable, or pendant-style mounting directly to ceiling structure, rafters, or conduit. The H2309 linear fixtures mount via steel wire rope (included). Both styles connect to an existing junction box or conduit feed; a licensed electrician should make the final electrical connection for commercial installations. Installation typically takes 15–30 minutes per fixture once the mounting point is established.

• Do the lights work on 120V, 240V, and 277V circuits?

  Yes. All GJIA UFO and linear high bays accept AC 100–277V (UFO models) or AC 120–277V (H2309 linear), making them compatible with virtually every North American electrical system — 120V single-phase residential panels, 208V or 240V commercial circuits, and 277V single-phase industrial distributions. No transformer or voltage converter is needed anywhere in the US or Canada.

• What is 0-10V dimming, and what do I need to use it?

  0–10V dimming is the industry standard low-voltage control protocol for commercial and industrial LED fixtures. A separate 0–10V dimmer or controller (sold separately) sends a control voltage between 0 and 10 volts to the driver's purple and grey control wires. At 10V the light runs at full output; at 0V most drivers dim to minimum (typically 10% output). To use dimming with GJIA high bays, you need: (1) a 0–10V compatible wall dimmer or lighting control panel, and (2) 18–2 AWG low-voltage control wire run from the dimmer to each fixture group. The dimming function is separate from the selectable wattage switch.

• Does the H2309 Linear high bay come with a motion sensor?

  Yes — the H2309 includes a built-in PIR (passive infrared) motion sensor. This automatically dims or turns off the fixture when no motion is detected, providing significant energy savings in intermittently occupied areas such as warehouse aisles, storage rooms, and break areas. Spaces with motion sensor control typically achieve 70–80% additional energy savings on top of the LED energy reduction compared to fluorescent systems. The sensor works in combination with the 0–10V dimming circuit.

• Can I daisy-chain or link multiple high bay fixtures together?

  For 0–10V dimming control, multiple fixtures can be connected to a single 0–10V dimmer by running the control wire in parallel through the group. The dimmer's sink current capacity should be checked against the number of fixtures (each fixture typically draws less than 2 mA on the control circuit). For power wiring, standard branch circuit rules apply — consult a licensed electrician for load calculations and circuit sizing.

• The UFO models list a single color temperature — what is it?

  The GJIA UFO HB Series and L2204 Adjustable Series are fixed at 5000K, a crisp daylight-white that closely mimics natural sunlight. This is the preferred color temperature for industrial facilities, warehouses, and manufacturing plants because it maximizes contrast and color rendering for task work, barcode scanning, and quality inspection. The Linear H2309 offers CCT selection between 4000K (neutral white, softer appearance, preferred for retail and commercial spaces) and 5000K (cool daylight, preferred for industrial use).

• How do I calculate how many high bay lights I need for my warehouse?

  Use this formula: Number of Fixtures = (Floor Area in sq ft × Target Foot-Candles) ÷ (Lumens per Fixture × Coefficient of Utilization × Light Loss Factor). Typical values: Target foot-candles are 20–30 fc for general warehouse storage, 30–50 fc for manufacturing, and 50 fc for detailed task areas. Coefficient of Utilization (CU) is approximately 0.55–0.65 for high-ceiling industrial spaces. Light Loss Factor (LLF) is typically 0.80. Example: a 10,000 sq ft warehouse with 25 ft ceilings targeting 30 fc with 30,000 lm fixtures (200W) → (10,000 × 30) ÷ (30,000 × 0.60 × 0.80) = 20.8 → approximately 21 fixtures.

• What is the recommended spacing between fixtures?

  A general rule is to space fixtures apart at roughly 1.0–1.5 times the mounting height above the work plane. For 20 ft mounting height: space fixtures 20–30 ft apart. For 25 ft: 25–37 ft apart. For 30 ft: 30–40 ft apart. Keeping the spacing-to-height ratio at or below 1.5 prevents dark spots between fixtures. For linear high bays in aisles, align one fixture directly above each aisle centerline.

• What foot-candle levels do different applications require?

  Recommended foot-candle (fc) targets by space type: General warehouse storage: 10–30 fc. Manufacturing / assembly: 30–50 fc. Auto dealership showroom: 50–75 fc. Gymnasium (recreational): 30–50 fc. Gymnasium (competition): 50–75 fc. Distribution center pick-and-pack: 50 fc. Large retail floor: 40–60 fc. The GJIA 150W UFO delivers approximately 22,500 lm — sufficient for standard warehouse storage at 20–25 ft mounting height. The 300W and 400W models are appropriate for facilities requiring 50+ fc at 30–40 ft ceilings.

• What is the difference between ETL and DLC certification?

  ETL (tested by Intertek) is a product safety certification, equivalent to UL listing, confirming the fixture meets North American electrical safety standards. Both ETL and UL marks are recognized by OSHA as NRTL (Nationally Recognized Testing Laboratory) certifications and are accepted by AHJs (Authorities Having Jurisdiction) for commercial installations across the US and Canada. DLC (DesignLights Consortium) is a separate performance certification focused on energy efficiency — it confirms that the fixture meets minimum efficacy, reliability, and quality thresholds. DLC listing is typically required to qualify for utility rebates and incentive programs.

• What does IP65 mean for a high bay light?

  IP65 is an IEC 60529 protection rating: '6' means fully dust-tight (no ingress of dust), and '5' means protected against water jets from any direction. For warehouse and industrial high bay lights, IP65 is the minimum recommended protection level. It ensures the fixture withstands dusty environments (grain elevators, woodworking shops, metal fabrication), high-humidity areas (food processing, car washes), and cleaning with pressure hoses or steam. It does not indicate full submersion protection.

• What does IK08 mean, and why is it important for gymnasiums and factories?

  IK08 is an IEC 62262 mechanical impact protection rating, indicating the fixture can withstand a 5-joule impact without damage to the lens or housing. In practice, this means a hard blow from a tool, a stray basketball, or accidental forklift contact will not shatter the polycarbonate lens or compromise the fixture. IK08 is particularly important in gymnasiums, sports courts, manufacturing floors, and warehouse environments where equipment, vehicles, or athletic balls could strike overhead fixtures.

• Does the Linear H2309 have a different certification than the UFO models?

  Yes. The H2309 Linear high bay is UL Listed (Underwriters Laboratories) and FCC/RoHS compliant, rated for damp locations. The damp location rating means it can be installed in areas exposed to moisture, such as covered outdoor areas, parking structures, car washes, and industrial facilities with high humidity. UL listing is the most widely recognized safety certification in the US and is accepted by virtually all AHJs.

• Are GJIA high bay lights eligible for utility rebates in the US and Canada?

  DLC-listed products (GJIA HB Series 150W–240W and L2204 100W–240W) are the most widely eligible for commercial lighting rebates in the US and Canada. Most electric utilities, state energy offices, and provincial programs require DLC listing as a baseline qualification. Rebate amounts vary widely — typically $20–$80 per fixture for commercial retrofit projects. Contact your local utility or visit the DLC's online QPL (Qualified Products List) to confirm eligibility. The 300W and 400W L2204 models are ETL-only and may not qualify for all rebate programs.

• What is the best GJIA high bay for an auto dealership?

  The HB White Series (150W or 200W) is the most popular choice for auto dealerships. The white housing delivers a clean, professional look over showroom floors; the 5000K color temperature renders vehicle paint colors accurately with high contrast; the DLC listing makes it eligible for commercial lighting rebates. For service bays and maintenance areas, the black HB Series or L2204 Adjustable in 200W–240W provides maximum brightness for detailed mechanical work.

• Can the GJIA UFO high bays be used outdoors?

  The IP65 rating protects against dust and water jets, making UFO high bays suitable for covered outdoor areas such as loading canopies, covered parking structures, outdoor sports courts with overhead protection, and semi-exposed industrial areas. They should not be fully exposed to direct rain without overhead cover. For fully outdoor applications, look for fixtures with a wet location rating (typically IP66 or IP67). The H2309 linear is rated for damp locations, appropriate for covered outdoor or high-humidity indoor areas.

• What is the minimum ceiling height for installing a GJIA UFO high bay?

  GJIA UFO high bays are designed for ceilings 15 feet and above. Below 15 feet, the concentrated beam of a UFO fixture can create excessive glare and uneven illumination. For ceilings under 15 feet, a low bay fixture or the H2309 Linear (with its 90° diffused beam) is more appropriate. The 100W L2204 model is suitable for ceilings as low as 12–15 ft in automotive shops and small commercial spaces.

• Are the lights suitable for a sports gymnasium with direct glare concerns?

  Yes, with two caveats. For ceiling heights 20 ft and above, UFO high bays (IK08 impact rated) work well in gymnasiums — hang them higher to reduce direct glare impact, and use the 0–10V dimming to adjust brightness for different activities (practice vs. competition). For lower ceilings (15–20 ft) or for court-level glare sensitivity, the H2309 Linear with its prismatic diffuser produces softer, more uniform light. The white HB Series housing also improves the visual environment in commercial and recreational spaces.