Gas, sodium vapor or LED: a conversion is always worthwhile.

When Sabine, the technical director of a municipal construction yard, opens the annual inventory list of street lighting, it feels like a time travel report: In the historic district, there are still some gas lamps. On the main road, high-pressure sodium vapor lamps are in operation – reliable, but energy-hungry. And in several new housing developments, LED lamps are already hanging, which are technically 'modern,' yet still operate rigidly on a timer at night.

Sabine's challenge is typical: The city is supposed to save, become more sustainable, and still maintain safety in public spaces. A complete replacement of all poles and lights would be ideal – but hardly manageable financially and organizationally. This is exactly where the retrofit concept comes into play: Continue to use existing infrastructure, modernize where it brings the greatest effect, and gradually grow into a future-proof, connected lighting system.

What types of street lighting still exist today?

In many cities, several generations stand side by side. This is not a disadvantage – as long as the modernization is wisely planned:

Gas lighting is usually part of the urban landscape and is of cultural-historical value, but is cumbersome and inefficient in operation. Where gas is still used, a strategic decision is often worthwhile: preservation at representative locations – and conversion at sites where energy efficiency and operational reliability are the focus.

Sodium vapor (and other conventional discharge lamps) are still in use in main streets and older residential areas in many places. The leap to LED is particularly effective here: Simply switching to LED significantly reduces energy consumption and improves controllability.

LED lamps are now widely spread – but "LED" alone does not mean "smart." Many LED installations run without adaptive dimming, without status data, and without central adjustment. Those who retrofit here often unlock a second efficiency step: less electricity during off-peak times, better control, and less maintenance effort.

When does retrofit make sense – and when doesn’t it?

Retrofit is particularly worthwhile when the load-bearing structure (pole, foundation) and large parts of the installation are still in good condition. Instead of initiating large construction projects, targeted modernization is carried out: light fixtures, drivers, control, and communication – depending on the starting situation.

A short practical checklist helps with the decision:

• Is the pole mechanically sound and does it still have sufficient remaining lifespan?

• Can the light fixture be meaningfully reused or is an LED conversion already planned?

• Is there a need for dimming, switching profiles, remote monitoring, and quick maintenance?

If several points are answered "yes," retrofit is usually the fastest way to measurable results – without discarding the existing setup.

The retrofit approach: resource-conserving modernization

The core idea of retrofit is simple: preserve as much as possible, modernize as much as necessary. In practice, this often means: The lantern pole remains because it fits structurally. And even with existing LED lights, there are often options to prepare them for light management and networking – for example, by choosing compatible components during already planned maintenance cycles.

An important building block for future-proof retrofitting is cross-manufacturer interfaces. At ENVIOTECH, the EnvioLux Node is designed for lights with Zhaga Book 18. This interface makes it easier to retrofit intelligent functions without having to replace the entire light fixture each time – provided that the fixture supports the standard or is selected accordingly during an LED conversion.

Why retrofit remains interesting even with already retrofitted LEDs

Many municipalities have already completed the first step – LED. The second step is "optimizing operation": adaptive dimming profiles, demand-responsive lighting, transparency over energy consumption, and early detection of faults. This way, a "bright" street becomes a controllable street – resulting in more safety and predictability in daily life.

And it’s not just about lighting: connected lights can become part of a smart infrastructure – as a platform that can be expanded with additional sensors as needed. A modular structure is important: start today, expand tomorrow, without the city having to build anew each time.

Conclusion: Modernize without demolition – that is the retrofit advantage

Whether gas, sodium vapor, or LED: In almost every situation, there is a retrofit path that brings costs, resources, and implementation speed into a good balance. For Sabine, this means: first modernize where the effect is greatest – and position the lighting so that it can grow along with it in the coming years.

Learn more about retrofit and connected street lighting with ENVIOTECH