How to prevent condensation in outdoor luminaires

Condensation is one of the main threats to outdoor luminaires. Although it often goes unnoticed, it can seriously compromise both the performance and lifespan of the product if the right precautions are not taken. Understanding how this phenomenon occurs and what solutions are available is key to ensuring efficient and long-lasting installations.

During the operation of an outdoor luminaire — especially those with a medium or high degree of ingress protection — the heat generated by the light source warms the air trapped inside the luminaire’s housing. As with all gases, when the temperature increases, the air expands and occupies more space.

The issue begins once the luminaire is switched off: the warm air starts to cool, contracts, and creates a vacuum. This drop in pressure acts as a suction mechanism that, over time, draws in ambient moisture through the wiring, specifically via the copper strands of the power cable. It’s a slow but relentless process that can eventually damage internal components, reduce the lifespan of the luminaire and impair its performance.

Correct installation is the first step towards minimising this issue. In addition, for luminaires that need to be opened to install or replace the light source, it is essential to follow a simple but effective procedure: operate the luminaire for one hour without the protective glass or cover, and then close it immediately after that period.

Condensation is not a manufacturing defect nor a product flaw, but a natural physical consequence of environmental conditions and equipment usage. However, applying practical and technological solutions like those described above can minimise its effects and ensure optimal performance even in the most demanding environments.