LED versus legacy sources compared: retrofit and refurbishment of existing installations

Overview

The comparison between LED and discharge sources is settled on efficiency, but it remains useful to understand which differences really affect the operation of a retrofit and refurbishment of existing installations installation and which are marginal. Most projects do not start from scratch: they work on existing installations, with poles, lines and constraints already in place.

Applicable standards

The regulatory reference for retrofit and refurbishment of existing installations is not a single document but a coordinated set of standards covering performance, safety and environmental impact. In design practice the following documents drive the main choices.

• EN 13201 / EN 12464 — performance requirements to be met.
• IEC 60364 — verification of the existing electrical installation.
• Italian CAM for lighting — constraints in public projects.

The criteria that matter

A serious technical comparison does not stop at consumption. The relevant differences concern distribution control, dimming capability, start-up behaviour, depreciation over time and maintainability. On each of these points LED behaves differently from discharge sources, with practical consequences for how the installation is designed and operated.

Operational differences

• Beam control — Limited by source size — High, dedicated optics per point
• Dimming — Limited, with restrike constraints — Continuous, no restrike constraints
• Start-up — Ignition and hot-restrike time — Instant
• Depreciation — Managed by periodic lamp replacement — Gradual, driven by thermal design
• Maintenance — Frequent lamp replacement — Rare interventions but on electronics

Design implications

Moving to LED changes maintenance logic: from frequent scheduled replacements to rare but more technical interventions, often on electronics. It also changes design logic, because dimmability allows the installation to be sized on differentiated scenarios instead of a single fixed level. In the overall balance these two aspects matter more than the instantaneous power saving.

Recurring critical points

The difficulties that most often emerge in retrofit and refurbishment of existing installations projects are not about product selection, but about defining requirements and verifying results.

• Assessing the real condition of poles, lines and boards before replacing luminaires.
• Avoiding energy savings that mask a failure to meet standards.
• Scheduling works to reduce disruption for residents and users.

Design approach

An orderly method drastically reduces variations during works and disputes at commissioning. Three choices make the difference from the earliest stages.

• Detailed asset survey with a record per light point and structural checks on supports.
• A lighting design proving compliance with the required classes.
• Functional lots by homogeneous area with progressive commissioning.

Parameters to verify

• Asset survey — good practice — record per light point
• Compliance check — EN 13201 / 12464 — classes and requirements achieved
• Electrical condition — IEC 60364 — boards, protection, leakage
• CAM requirements — Italian CAM — mandatory in public works

Most frequent mistakes

Non-conformities found at commissioning almost always come from three causes: requirements not declared or declared without a reference standard, calculation run on idealised geometry, and an optimistic maintenance factor. All three can be avoided at zero cost during design.

Key takeaways

A retrofit and refurbishment of existing installations project holds up over time when requirements are declared, the calculation reproduces real conditions and on-site verification follows an agreed protocol. Component selection matters, but comes later: without measurable requirements even the best product delivers a result that cannot be demonstrated. Centro Studi Lumeitalia makes its technical office available to review requirements and design checks.

Methodological note: This content is written for technical information purposes by Centro Studi Lumeitalia and does not replace the lighting design or a full reading of the standards cited. Applicable performance values are those of the standards in force at design time.

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