The B2B Dilemma: Retrofit vs. Replace
Disclosure: This guide is provided by the technical team at Hyperlite. While we manufacture LED lighting solutions, the following analysis is based on industry standards (IES, DLC, ASHRAE) and field data collected from commercial audits to provide an objective framework for facility managers.
For facility managers and property owners, outdoor lighting is a calculated capital expenditure (CapEx) decision involving security, liability, and long-term operational costs (OpEx). When an existing high-pressure sodium (HPS) or metal halide (MH) wall pack begins to fail, or when energy mandates require the addition of occupancy sensors, a critical question arises: Should you retrofit the existing fixture with a sensor and LED kit, or replace the entire unit with a modern, integrated LED wall pack?
While the material cost of a standalone sensor may appear lower, the "Payback Math" frequently reveals a different reality. Labor rates, utility rebate structures, and long-term lumen maintenance often tilt the scales toward full fixture replacement.
The Hidden Labor Trap in Retrofit Projects
A common oversight in lighting audits is underestimating the "fully burdened" cost of labor. Based on common patterns observed in industrial site audits, adding a sensor to an existing fixture is rarely a "simple add-on."
The "Bucket Truck" Factor
Most outdoor wall packs are mounted between 12 and 20 feet. Accessing an older fixture often requires a bucket truck and, for safety compliance, two personnel. According to national data from Angi, professional electricians typically charge between $50 and $150 per hour.
Observed Labor Benchmarks:
- Full Replacement: 30–45 minutes per unit. (Disconnect, unmount, mount new unit, connect).
- Sensor Retrofit: 60–90 minutes per unit. (Open housing, troubleshoot existing wiring, drill for sensor mounting, splice, re-seal).
Wiring Complexity: Class 1 vs. Class 2
Modern LED wall packs often utilize 0-10V dimming. Retrofitting a sensor into an old housing may require pulling new low-voltage control wires through existing conduits that may already be at capacity. This introduces "friction points" like cable tension limits and potential interference. In contrast, a new integrated fixture is factory-prewired, ensuring the sensor-to-driver connection is optimized and weather-sealed.
| Metric | Retrofit (Sensor Add-on) | New Integrated LED Fixture |
|---|---|---|
| Estimated Labor Time | 60–90 Minutes | 30–45 Minutes |
| Wiring Risk | Moderate (Field Splicing) | Low (Factory Integrated) |
| System Warranty | Component Only | Full System (Typically 5 Years) |
| Ingress Risk | Higher (Due to field drilling) | Minimal (IP65 Factory Seal) |
The Rebate Gap: DLC Premium vs. Standard Retrofits
The DesignLights Consortium (DLC) Qualified Products List (QPL) is the primary gatekeeper for utility rebates in North America. To maximize ROI, B2B buyers should evaluate the distinction between DLC Standard and DLC Premium.
Utility programs often offer tiered incentives. In many jurisdictions, a DLC Premium fixture receives a $25 to $75 higher rebate per unit than a standard retrofit kit. This is because integrated fixtures provide a "known" performance profile. A retrofit kit's efficiency can be compromised by the old fixture's yellowed lens or inefficient internal reflectors.
Regional Compliance Variations
- California (Title 24): Mandates specific occupancy and daylighting controls for most outdoor lighting upgrades. Integrated sensors are often the most cost-effective way to meet these stringent requirements.
- Northeast (Efficiency Vermont/Mass Save): Often provides higher "upstream" rebates for DLC Premium fixtures, which can sometimes reduce the hardware cost to near-parity with retrofits.
Title 24 Controls for Warehouse High Bay Lighting provides further context on how these mandates impact large-scale facility upgrades.
Technical Performance: LM-79, LM-80, and Optics
While both options save energy compared to old HID systems, a new integrated fixture can yield an additional 10–15% efficiency gain due to advanced optics and superior thermal management.
Interpreting Performance Reports
- LM-79-19: Measures the performance of the entire fixture. Retrofit kits often cite "chip lumens," which do not account for light lost (up to 30%) through an old, degraded fixture housing.
- LM-80 and TM-21: Used to project the L70 life—the point where light output drops to 70%. Integrated wall packs use the aluminum housing as a heat sink, keeping LEDs cooler than a kit stuffed into a confined, unventilated box. This often results in an L70 life exceeding 60,000 to 100,000 hours.
The 5-Year Rule of Thumb: A Decision Matrix
Based on standard depreciation cycles and component degradation, facility managers can use this heuristic for initial planning:
- If the existing fixture is < 5 years old and LED-ready: A sensor retrofit may be viable. The housing and lens are likely in good condition, and the "sunk cost" hasn't been fully depreciated.
- If the existing fixture is > 5 years old or HID-based: Replacement often represents a superior long-term Total Cost of Ownership (TCO). The gains in efficacy, higher rebates, and a reset of the warranty period provide a more robust ROI.
Scenario Analysis: 20-Unit Security Perimeter
Assumptions: $0.12/kWh, 12 hours/day operation, $100/hr labor rate.
| Cost Component | Retrofit (Sensor Only) | New Integrated Fixture |
|---|---|---|
| Hardware Cost | $40 (Sensor) | $110 (Full Fixture) |
| Labor (Per Unit) | $150 (1.5 hrs) | $75 (0.75 hrs) |
| Utility Rebate | $10 (Standard) | $50 (DLC Premium) |
| Net Cost Per Unit | $180 | $135 |
| Total Project Cost | $3,600 | $2,700 |
| Warranty | None (on housing) | 5-Year Full System |
In this scenario, the "more expensive" hardware results in a lower net project cost and a vastly superior technical outcome.
ROI Calculation Template
To perform your own audit, use the following formula for each fixture type:
Net Cost = (Fixture + Labor + Equipment Rental) - Utility Rebate
Annual Savings = (Old Watts - New Watts) / 1000 * Annual Hours * Rate
Simple Payback (Years) = Net Cost / Annual Savings
Note: For a more detailed analysis, include the "Avoided Maintenance Cost" of not having to repair old ballasts or seals over the next 5 years.
Summary Checklist for Facility Managers
Before finalizing a lighting upgrade, perform this technical audit:
- Verify Rebate Eligibility: Search the DLC QPL for the specific model number.
- Audit Labor Quotes: Ensure the contractor has accounted for lift rentals and potential wiring complexities.
- Check Voltage Compatibility: Verify the sensor’s datasheet matches the existing driver’s voltage (e.g., 120-277V or 347-480V).
- Assess Lens Condition: If the old lens is yellowed, expect a 20-30% loss in effective light, which may compromise security camera footage.
- Request IES Files: For large projects, use IES files in software like AGi32 to ensure the layout meets ANSI/IES RP-7 standards.
Frequently Asked Questions (FAQ)
Can I use a 0-10V sensor with an older LED driver? Only if the driver has dedicated dimming leads (usually purple and gray/pink). If the driver is not dimmable, a standard occupancy sensor can only provide ON/OFF functionality, which may not meet "bi-level" dimming requirements in modern energy codes.
Does a retrofit kit void the original UL listing of the fixture? In many cases, yes, unless the kit is "UL Classified" specifically for that fixture housing. This can create a liability risk; installing a new UL Listed fixture avoids this legal ambiguity.
Is 5000K or 4000K better for outdoor security? 5000K (Daylight White) is often preferred for security because it provides higher contrast for surveillance cameras. However, 4000K is frequently chosen in residential-adjacent areas to reduce blue-light pollution.
YMYL Disclaimer: This article is for informational purposes only and does not constitute professional electrical engineering or financial advice. Local codes and utility rebate programs vary significantly by region. All electrical installations must be performed by a licensed professional in accordance with the National Electrical Code (NEC) and local building regulations. Consult with a tax professional regarding specific energy tax credits.