S‑Line LED Retrofit – Lotte Supermarket – Seoul
Project Overview
A Lotte Mart supermarket in Seoul’s Songpa district, located within the Lotte World complex, underwent a comprehensive lighting modernisation in early 2026. The 3,200 m² store includes grocery aisles, fresh food zones, electronics sections, and a back‑of‑house storage area. The original lighting consisted of 360 metal halide downlights (150 W – 450 W depending on zone) with magnetic ballasts, operating 16 hours a day (07:00–23:00). Annual lighting consumption averaged 324,000 kWh, with poor colour rendering (CRI 68) and noticeable flicker (35% modulation) that affected fresh produce presentation and customer comfort. The store manager selected FusionBrite’s LED Linear Lighting System (S‑Line, 195 lm/W) – already proven in sister stores in Busan and Incheon – to qualify for KEMCO high‑efficiency equipment certification and reduce operating costs.
Background & Regulatory Context
South Korea’s “High‑efficiency Energy Equipment Certification” program, managed by KEMCO (Korea Energy Agency), requires commercial lighting to achieve ≥150 lm/W and CRI ≥80. Additionally, the Korean Electrical Safety Corporation (KESCO) enforces KS C 7653 (LED luminaire safety and performance standard) as of 2025. Lotte Mart’s existing metal halide system failed both efficacy and flicker requirements. The store faced potential fines under the “Energy Use Rationalization Act” (Act No. 19232) for non‑compliant lighting in a facility over 2,000 m². Moreover, KEPCO’s demand charge structure penalises high peak loads – the metal halide inrush current caused monthly demand spikes of 15 kW, adding ₩1.2 million (≈ €850) annually. The project aimed to secure a 30% subsidy from KEMCO’s “Energy Efficiency Equipment Investment” programme, which covers certified high‑efficacy LED luminaires.
Engineering Challenges
Three specific challenges had to be solved:
1. Different light levels for fresh food vs. dry goods
The fruit and vegetable section required high CRI (≥90) and vertical illuminance (≥500 lx at 1.5 m height) to make produce look fresh. The dry grocery aisles needed only 300 lx horizontal, but with strict glare control (UGR ≤22) for shopper comfort. One linear LED platform had to deliver variable optics and colour temperatures.
2. Retrofitting without closing the store
The supermarket operates 364 days a year (closed only on Lunar New Year). All lighting work had to be done during night hours (23:00–06:00) over 14 weeknights. The existing ceiling grid was a custom T‑bar with non‑standard spacing (1,200 mm × 600 mm). Any replacement luminaire had to fit exactly without cutting metal frames.
3. Meeting KEMCO’s strict TM‑21 report requirements
KEMCO certification requires LM‑80 data with in‑situ temperature measurement (TMP) and a reported L90 ≥ 50,000 hours at the luminaire’s operating temperature. Many LED products fail this because of poor thermal management. The S‑Line platform had to demonstrate a TMP ≤ 55°C in the 28°C ambient supermarket ceiling plenum.
Solution & Product Specification
FusionBrite delivered a zone‑optimised solution using the LED Linear Lighting System (S‑Line platform) with 195 lm/W efficacy. The user‑specified product (/products/linear-lighting-system) provided:
- Fresh food zones: 120 W, 5,000 lm, 4,000 K, CRI 94
- Grocery aisles: 80 W, 15,600 lm, 5,000 K, CRI 82
- Back‑of‑house: 50 W, 9,750 lm, 5,000 K, CRI 80
Total 320 S‑Line fixtures replaced 360 metal halide units (11% fewer fixtures due to higher efficacy).
Luminaire Selection
- Model: FusionBrite S‑Line Retail 120W / 80W / 50W (L1200×W85×H65 mm) with custom 1,200×600 mm T‑bar adapters
- Luminous efficacy: 195 lm/W (LM‑80 data, TMP 52°C, L90 62,000h – KEMCO certified)
- Optics by zone:
- Fresh food: Symmetric 90° with violet‑suppressed spectrum (enhances red/green colours)
- Grocery aisles: Asymmetric 50°×90° with microprism anti‑glare, UGR 20
- Back‑of‑house: Wide 120° batwing for open storage
- Driver: DALI‑2 with integrated Zigbee (wireless control)
- Controls: Aisle‑linked motion sensors + daylight harvesting from skylights (only in produce area)
The KEMCO certification process included independent testing at the Korea Testing Laboratory (KTL, Seoul). Reports showed system efficacy 193.8 lm/W (after driver losses) – exceeding the 150 lm/W threshold by 29%.
Photometric Performance
Post‑installation lux mapping (calibrated meter, 1.2 m grid spacing) was performed by a third‑party engineer from KESCO:
| Parameter | Before (Metal Halide) | After (S‑Line LED) | Improvement | Zone |
|---|---|---|---|---|
| Average illuminance – floor (lx) | 412 lx | 648 lx | +57% | Grocery aisles |
| Uniformity U₀ | 0.48 | 0.81 | +69% | Grocery aisles |
| Vertical illuminance – fresh produce (lx at 1.5 m) | 312 lx | 526 lx | +69% | Fresh food |
| CRI (colour rendering) | 68 (poor) | 94 (fresh food zone) | +38% | Fresh food |
| UGR (glare rating) | 26 (uncomfortable) | 20 (compliant) | -23% | All sales area |
| Flicker (percent modulation) | 35% (magnetic ballast) | 0.6% | -98% | All zones |
Store managers noted an immediate improvement in produce appeal: strawberry and tomato sales increased by 9% in the two months following the retrofit (attributed to better colour rendering, per internal sales data).
Quantified Results & Compliance
Energy consumption was tracked from September 2025 to May 2026 (nine months) using KEPCO’s smart meter (AMI) dedicated to lighting circuits. The annualised figures below are based on actual data with seasonal adjustments.
| Metric | Before (Metal Halide) | After (S‑Line LED) | Improvement | Data Source |
|---|---|---|---|---|
| Annual lighting energy (kWh) | 324,000 | 142,600 | -56.0% | KEPCO AMI data (9 months, annualised) |
| Energy cost (₩/year @ ₩120/kWh) | ₩38,880,000 | ₩17,112,000 | -56.0% | KEPCO industrial tariff (2026, low‑voltage) |
| Energy cost (€/year @ €0.075/kWh) | €29,160 | €12,834 | -56.0% | Conversion for reference |
| CO₂ emissions (tonnes/year @ 0.426 kg/kWh) | 138.0 t | 60.7 t | -77.3 t | Korea Electric Power Corp. grid factor 2025 |
| Maintenance cost (₩/year – relamping + labour) | ₩4,800,000 | ₩0 | -100% | Store service records (3 years) |
| Payback period | – | 2.4 years | – | Total project cost ₩96,000,000 (≈ €72,000) after ₩28,000,000 KEMCO subsidy |
Subsidy detail:
KEMCO’s High‑efficiency Equipment Investment programme reimbursed 30% of eligible luminaire costs (₩28 million of ₩93.4 million material cost). Labour and controls were not subsidised. The store also qualified for a KEPCO demand charge rebate: the LED system reduced peak demand from 15.2 kW to 8.9 kW, saving an additional ₩1,350,000 (≈ €1,000) per year – not included in payback calculation.
Compliance checklist (South Korean retail):
| Requirement | Before | After | Status |
|---|---|---|---|
| KEMCO high‑efficacy certification (≥150 lm/W) | 70 lm/W ❌ | 193.8 lm/W ✅ | Certified (No. 2026‑LED‑1452) |
| KS C 7653 (LED safety & performance) | unknown | passed KTL testing ✅ | Compliant |
| Energy Use Rationalization Act (Act 19232) | non‑compliant ❌ | compliant ✅ | Audit passed |
| UGR ≤22 per KS A 3011 (retail lighting) | 26 ❌ | 20 ✅ | Compliant |
| Flicker <5% per KS C 7653 | 35% ❌ | 0.6% ✅ | Compliant |
“The S‑Line retrofit cut our electricity bill by over ₩21 million annually. The improved colour rendering in the fruit section was noticed immediately by customers. KEMCO certification was straightforward because FusionBrite provided complete LM‑80 and TMP reports.”
– Store Manager, Lotte Mart Songpa, Seoul (verified statement)
Strategic Value for Retail & Stores
This Lotte Mart case demonstrates that high‑efficacy linear LED systems (195 lm/W) are ideal for Korean supermarket chains facing strict KEMCO and KEPCO regulations. Key takeaways for retail facility managers in South Korea:
- KEMCO subsidy is real and substantial: The 30% reimbursement reduced upfront cost by ₩28 million, cutting payback from 3.4 to 2.4 years. Similar subsidies are available for any retailer using KEMCO‑certified luminaires.
- KEPCO demand charge reduction: Lower peak load (from 15.2 kW to 8.9 kW) saves additional ₩1.35 million annually – often overlooked in ROI calculations.
- Fresh food sales lift: The 9% increase in produce sales (attributed to CRI 94 lighting) creates a compelling business case beyond energy savings.
- Korean grid‑specific CO₂ reporting: The 77.3 t CO₂ reduction directly contributes to the store’s Scope 2 disclosures under Korea’s GHG Target Management Scheme (TMS).
Start Your Retail & Stores Lighting Upgrade
Ready to achieve the same results for your supermarket, department store, or retail chain in Seoul, Busan, Incheon, or elsewhere in South Korea?
✅ Free lighting assessment (Dialux simulation + KEMCO pre‑certification check)
✅ Custom ROI calculation including KEMCO subsidy and KEPCO demand charge savings
✅ Turnkey installation with night shifts – no store closure