See the real-world impact of a UFO high bay upgrade. This case study details how a 50,000 sq. ft. warehouse replaced legacy fixtures, cutting energy costs by 70% and achieving a full ROI in under 24 months. We will break down the audit, the specification process, the installation, and the verified results, providing a blueprint for facility managers and contractors.
The Challenge: Auditing an Outdated Lighting System
The project began with a comprehensive audit of the existing lighting in a 50,000-square-foot distribution center. The facility operated 18 hours a day, six days a week, and was illuminated by 120 aging 400-watt metal halide (MH) fixtures. The initial assessment revealed significant operational pains.
My first step on a project like this is always to measure what exists. Walking the floor with a photometer, we found illuminance levels were inconsistent, ranging from a dim 10 foot-candles (fc) in the aisles to 25 fc directly under fixtures. This inconsistency, combined with the poor Color Rendering Index (CRI) of the MH lamps, made it difficult for workers to accurately read labels and identify products, impacting picking speed and accuracy.
Beyond performance, the costs were substantial:
- High Energy Use: Each 400W MH fixture actually consumed around 458 watts when accounting for the ballast. Running 120 of these for over 5,600 hours a year resulted in massive energy expenditure.
- Constant Maintenance: The MH lamps had a short lifespan, requiring replacement every 15,000-20,000 hours. This translated to a recurring cycle of purchasing lamps and renting scissor lifts, creating both direct costs and operational downtime.
- Poor Light Quality: The lamps produced a noticeable flicker and color shift as they aged, contributing to employee eye strain and fatigue.
The Solution: Data-Driven Specification and Design
Moving from a legacy system to LED is not just about a one-for-one swap. The goal is to design a system that delivers better, more efficient light. Our strategy focused on specifying a fixture that balanced performance, compliance, and long-term reliability.
Fixture Selection: Efficacy and Durability
We selected a 150-watt UFO-style LED high bay fixture for this retrofit. Specifically, a luminaire like the Hyperlite LED High Bay Light - Black Hero Series, 21750lumens is an ideal candidate for this type of application, offering the required performance and certifications.
Here’s a common misconception I encounter: that higher wattage equals brighter light. In reality, the critical metric is luminous efficacy, measured in lumens per watt (lm/W). The chosen 150W LED fixture delivers over 140 lm/W, while the old 400W MH system struggled to produce 55 lm/W. This efficiency is the primary driver of energy savings.
Key specification criteria included:
- DLC Premium Certification: This was non-negotiable. To secure utility rebates, a fixture must be listed on the DesignLights Consortium (DLC) Qualified Products List (QPL). I’ve seen projects lose thousands in rebates because the specified fixtures weren’t on this list. Always verify the exact model number before purchasing.
- UL/ETL Listing: For safety and code compliance, every fixture must be certified by a Nationally Recognized Testing Laboratory (NRTL). A UL Solutions Product iQ Database listing confirms that the product meets established safety standards like UL 1598, which is crucial for passing electrical inspections.
- IP65 Rating: Warehouses can be dusty and occasionally damp. An IP65 rating, defined by the IEC 60529 standard, ensures the fixture is sealed against dust ingress and can withstand low-pressure water jets, guaranteeing its survival in a typical industrial environment.
Legacy vs. LED: A Comparative Analysis
To visualize the upgrade's impact, we created a clear comparison. This data was essential for securing management buy-in.
| Metric | Legacy 400W Metal Halide | New 150W LED High Bay |
|---|---|---|
| Fixture Wattage | ~458 W (with ballast) | 150 W |
| Luminous Efficacy | ~55 lm/W | >140 lm/W |
| Rated Lifespan (L70) | 15,000 hours | >60,000 hours |
| Color Rendering Index (CRI) | ~65 | >80 |
| Annual Energy Use/Fixture | ~2,574 kWh | 842 kWh |
| Rebate Eligibility | None | DLC Premium Qualified |
Layout and Photometric Simulation
A frequent mistake is failing to properly plan the fixture layout. We used IES photometric files for the new fixtures to model the lighting distribution in AGi32 software. This allowed us to determine the optimal spacing to achieve our target of a uniform 40 fc throughout the open areas and 30 fc in the aisles.
A practical rule I follow is the spacing-to-mounting-height (S/H) ratio. For the wide 120° beam angle of the UFO fixtures in the open areas, we used an S/H ratio of 1.2. This means for a 25-foot mounting height, the fixtures were spaced approximately 30 feet apart to ensure overlapping beams and prevent dark spots.
The Installation: A Focus on Efficiency and Safety
With a solid plan, the installation phase focused on minimizing disruption to warehouse operations. The project was completed in sections over two weekends.
One of the most valuable tools for a staged retrofit is temporary lighting. Using plug-and-play fixtures like the Hyperlite 50ft Construction LED String Work Lights allowed us to safely illuminate sections where the main power was shut down for the swap-out. This prevented any "lights-out" period that would have halted warehouse activity.
From this project, we learned several lessons that are now part of my standard procedure:
- Always Use Safety Cables: UFO fixtures are suspended from a hook, but a secondary safety cable is a must. It’s a simple, low-cost step that prevents a fixture from falling in the event of a primary mounting failure.
- Verify Dimming Control: The new fixtures were 0-10V dimmable to accommodate future occupancy sensors. A common pitfall is mismatching passive sensors with drivers expecting an active signal. We verified compatibility before purchasing the controls, preventing a nightmare of flickering and rework.
- Account for Inrush Current: When you energize a large bank of new LED drivers, the initial inrush current can be much higher than the steady-state load, potentially tripping breakers. We staggered the circuits to manage this and avoid nuisance trips during power-up.
- Commissioning is Key: Don't just flip the switch and walk away. We performed a post-installation check, spot-measuring light levels to confirm they matched our photometric model and checking driver temperatures to ensure proper heat dissipation.
The Results: 70% Energy Reduction and Rapid ROI
The outcome of the retrofit exceeded expectations. Post-installation measurements confirmed uniform light levels at our 40 fc target, a dramatic improvement in visual acuity that the warehouse staff immediately noticed.
The financial results were just as significant:
- Energy Savings: The total system wattage dropped from 54.9 kW to 18 kW. This 67% reduction in power draw translated to a 70% reduction in annual energy costs, saving the company over $41,000 in the first year.
- Rebate Impact: Because we specified DLC Premium fixtures, the project qualified for a significant utility rebate of $12,000.
- Maintenance Elimination: The long 60,000+ hour lifespan of the LED fixtures eliminated the bi-annual lamp replacement cycle, saving an estimated $5,000 per year in materials and labor.
Return on Investment (ROI) Calculation:
- Total Project Cost: (Fixtures, Labor, Lifts) = $65,000
- Net Project Cost: (Total Cost - Rebate) = $53,000
- Total Annual Savings: (Energy Savings + Maintenance Savings) = $46,000
- Simple Payback Period: (Net Project Cost / Total Annual Savings) = 1.15 Years (approximately 14 months)
Key Takeaways for Your Next Warehouse Retrofit
This project proves that a well-executed lighting upgrade is one of the highest-return investments a facility can make. Success hinges on a few core principles:
- Audit First: Quantify your existing conditions. You cannot improve what you do not measure.
- Specify for Value, Not Price: Prioritize high-efficacy, certified fixtures. The upfront cost is quickly offset by energy savings and rebates. Ensure documentation like LM-79 and IES files are available.
- Model the Outcome: Use photometric software to create a lighting layout. This prevents coverage gaps and ensures you meet your target illuminance levels without over-lighting.
- Plan the Installation: Address safety, controls compatibility, and potential electrical issues like inrush current before the first fixture goes up.
- Verify and Document: Commission the new system and keep all documentation organized to secure your full utility rebate.
By following this data-driven approach, any facility can achieve similar results, transforming its lighting from a costly liability into a strategic asset that improves safety, productivity, and the bottom line.
Frequently Asked Questions (FAQ)
What is the difference between UL and DLC certification? UL (Underwriters Laboratories) is a safety certification. It ensures the product is safe from electrical and fire hazards. DLC (DesignLights Consortium) is a performance and efficiency certification. It verifies that the product meets high standards for energy efficacy and quality, which is what makes it eligible for utility rebates.
How high should I mount my high bay lights? This depends on the fixture's beam angle and your ceiling height. For UFO high bays in open areas with 20-25 ft ceilings, a common approach is to space them at a distance 1.0 to 1.2 times the mounting height. For aisles, a narrower beam optic and tighter spacing is required.
Are Hyperlite high bay lights dimmable? Yes, our Hero Series high bay lights feature 0-10V dimming functionality, allowing you to connect them to compatible dimmers and occupancy or daylight sensors for further energy savings.
What does the 5-Year Warranty cover? As detailed on our official FAQ page, Hyperlite offers a 5-year warranty that covers any quality issues. If a fixture fails to perform effectively, we stand by our commitment to resolve the problem.