Avoiding Mistakes When Retrofitting to LED: A Practical Checklist

What Does Retrofit and LED Retrofit Mean?

The term retrofit refers to the modernisation of existing technical systems through the targeted replacement of individual components. In lighting applications, LED retrofit means integrating modern LED technology into existing luminaires and fittings while decommissioning or removing outdated technology:

• Replacement of fluorescent lamps with LED lamps (LED lamp replacement)
• Inspection, optimisation and retention of the existing luminaire
• Standardised, compliant conversion without a complete system replacement

👉 A typical application is the 1:1 replacement of T5 or T8 fluorescent tubes with standardised LED retrofit tubes in accordance with IEC EN 62776*

To maintain CE conformity*, fire safety and compliance with electrical inspections (E-Check), the use of a compatible LED lamp is essential. The LED tube must meet the requirements for LED retrofit in accordance with IEC EN 62776* and match the existing socket. Key points:

✅ T5 LED tubes only for G5 sockets

✅ T8 LED tubes only for G13 sockets

LED retrofit tubes are therefore available for all common socket types (G5/G13) and in all standard lengths. In case of uncertainty, a qualified electrician or the manufacturer should be consulted.

T5 or T8 LED tube? Differences, comparisons and a clear recommendationT5 or T8 LED tube? Differences, comparisons and a clear recommendation

High-quality LED tubes feature an integrated driver and are operated directly at 230 V. External control gear must be rewired in accordance with applicable standards and properly decommissioned. Incorrect rewiring poses a safety risk and can impair both the efficiency and functionality of the lighting system.

✅ Conventional control gear (CCG/LCG):

For luminaires with CCG, a 1:1 retrofit can be carried out without modifying the luminaire. The starter is replaced with a dummy starter, thereby electrically bypassing the CCG/LCG.

✅ Electronic control gear (ECG):

For luminaires with ECG, the control gear is converted within the luminaire in accordance with EN standards and decommissioned by a qualified electrician.

Efficient and safe LED retrofit in accordance with IEC EN 62776Efficient and safe LED retrofit in accordance with IEC EN 62776

Alongside energy efficiency, service life is the most important factor determining the quality and cost-effectiveness of an LED tube — and therefore of the entire lighting system. The longer the service life, the higher the product quality and the lower the maintenance and replacement costs. Key criteria:

✅ L70 Rating ≥ 100,000 h (GLT LED TUBE: 130,000 h)

After 100,000 operating hours, the LED tube still delivers at least 70% of its initial luminous flux. The GLT LED TUBE achieves an L70 service life of 130,000 hours.

The L70 rating is therefore significantly more meaningful than generic “lifetime” claims without a reference value—and represents a key performance indicator for evaluating the cost-effectiveness of LED systems.

Note: Very low-cost LED tubes often achieve an L70 service life of only approx. 30,000 hours, typically due to lower component quality.

✅ Documented Failure Rate (GLT LED TUBE: < 1% at 50,000 h)

Fewer than 1% of installed LED tubes fail completely within the first 50,000 operating hours.

✅ Temperature Range –20 °C to +60 °C in Accordance with EN 62776

The LED tube is designed and tested for safe and compliant operation within an ambient temperature range of –20 °C to +60 °C. Typical applications in thermally demanding environments include power plants, steelworks and cold storage facilities.

The specified temperature range defines the permissible operating conditions under which the LED tube maintains both performance and service life. A verified and clearly defined operating temperature range is therefore a critical selection criterion and a key factor for operational reliability—not only in extreme environments, but also in standard industrial applications such as warehouses, logistics centres and car parks.

Discover the long-lasting GLT LED TUBEDiscover the long-lasting GLT LED TUBE

System efficiency* (the overall energy efficiency of the lighting system) is, alongside service life, the most significant economic lever. The following factors are critical:

✅ Integrated High-Performance Driver in the LED Tube

External control gear causes additional power losses and reduces the overall performance of the system.

✅ High Luminous Efficacy (Lumens per Watt)

Lumens per watt (lm/W) describe the energy efficiency of an LED. This metric indicates how much visible light (lumens) is generated per unit of power consumed (watts). Example:

• 150 lm/W → good efficiency
• 200 lm/W → very high efficiency (high-end range)
• 210 lm/W → GLT LED TUBE

✅ High-Quality Components, such as:

• High-class LEDs
• Aluminium carrier profile instead of plastic
• Impact-resistant polycarbonate cover/optics with high mechanical protection rating IK10 in accordance with EN 62262 (resistance to an impact energy of 20 joules)
• Components compliant with the International Food Standard (IFS) and approved for use in the food industry

LED tube connected directly to 230 V – without control gearLED tube connected directly to 230 V – without control gear

Light quality has a direct impact on work performance, safety and well-being. Common mistakes include selecting an inappropriate colour temperature or insufficient colour rendering.

✅ *Colour Temperature (K = Kelvin):

• 6,500 K → cool, technical (e.g. laboratory environments)
• 3,000 K → warm (e.g. residential environments)
• 4,000–5,000 K → standard for professional applications (offices, production, warehouses)

✅ *Colour Rendering (CRI/Ra):

• Ra 80 → standard
• Ra ≥ 90 → high colour accuracy for demanding applications

👉 Important: Always comply with the requirements of workplace lighting regulations (DIN EN 12464-1), which define lighting standards for indoor work environments.

A cost-effectiveness analysis determines when an LED retrofit project will pay for itself. It takes into account:

• Investment costs
• Energy savings
• Service life
• Maintenance costs

✅ Purchase or Light as a Service – Use the GLT Lighting Calculator

Use the GLT lighting calculator to determine your savings potential—whether you opt for purchase or a leasing model.

GLT calculatorGLT calculator

Rely on “Made in Europe” quality and verified environmental data. Around 80% of LED tubes currently originate from Asia and are neither repairable nor recyclable. At the end of their service life, they are typically disposed of as electronic waste.

We take a different approach. With the GLT LED TUBEGLT LED TUBE, we have developed an LED tube based on the principles of circular lightingcircular lighting:

✅ Made in Germany

✅ Environmental Product Declaration (EPD) in accordance with ISO 14025 and EN 15804

✅ ESG-compliant carbon footprint

✅ Repairability and GLT reusable system

✅ Recycling rate of approx. 90%

This is how circular lighting is implemented at German LED Tech.This is how circular lighting is implemented at German LED Tech.

Ensure compliance with the following standards (always verify the datasheet):

✅ IEC EN 62776* – LED retrofit for G5/G13

✅ EU Ecodesign Regulation 2024/1781 (ESPR)* – 
product quality, durability, repairability and recyclability

✅ RoHS Directive* – restriction of hazardous substances

✅ ENEC* – electrical safety and electromagnetic compatibility (EMC)

👉 Since August 2023, T5 and T8 fluorescent tubes have been banned. Continued operation may compromise the CE conformity* of your lighting system.

Overview of Regulations and Standards for LED ConversionOverview of Regulations and Standards for LED Conversion