{"id":37483,"date":"2026-10-26T08:00:00","date_gmt":"2026-10-26T07:00:00","guid":{"rendered":"https:\/\/jelproducts.nl\/?p=37483"},"modified":"2026-07-09T21:45:29","modified_gmt":"2026-07-09T20:45:29","slug":"how-ambient-heat-affects-the-light-output-of-led-fixtures","status":"publish","type":"blog","link":"https:\/\/jelproducts.nl\/en\/blog\/hoe-beinvloedt-omgevingswarmte-de-lichtopbrengst-van-led-armaturen\/","title":{"rendered":"How does ambient heat affect the light output of LED fixtures?"},"content":{"rendered":"

Ambient heat has a direct and measurable impact on the light output of LED fixtures. The higher the temperature around a fixture, the less light the device produces and the faster the LED chip ages. This effect plays a major role in industrial environments where heat is a constant factor, such as steel mills, foundries, paper production halls, or other environments with intensive heat sources. In this article, we answer the most frequently asked questions about the relationship between temperature and LED performance.<\/p>\n

What happens to LED chips at high temperatures?<\/h2>\n

At high ambient temperatures, the efficiency of an LED chip decreases. The chip produces less light per watt, the color temperature can shift, and the component's lifespan is significantly shortened. This is not a defect, but a physical fact: semiconductors perform less well as they heat up.<\/p>\n

What exactly happens is as follows: heat increases the resistance in the semiconductor, causing a greater proportion of the electrical energy to be converted into heat instead of light. This is called thermal saturation. The chip is, in a sense, overloaded not by current, but by temperature.<\/p>\n

An additional effect is the accelerated aging of the phosphor layer used in many LED chips to produce white light. At sustained high temperatures, this layer degrades more quickly, leading to color shift and a noticeable decrease in light intensity. In industrial environments where fixtures are continuously running, this is a serious concern.<\/p>\n

How much light output does an LED fixture lose through heat?<\/h2>\n

The light output of an LED fixture can decrease significantly at high ambient temperatures. Depending on the quality of the chip and the thermal design of the fixture, the loss can range from a few percent to more than 30% at extreme heat. This phenomenon is known as LED lumen depreciation<\/strong>.<\/p>\n

Manufacturers typically specify the light output of luminaires at an ambient temperature of 25\u00b0C. As the actual temperature rises, the actual light output decreases. At a temperature of 50\u00b0C, a noticeable difference can already be measured. At 80\u00b0C or higher, the loss can become so great that the installation no longer meets the lighting requirements for the workplace.<\/p>\n

This is exactly why it is essential in the selection of LED fixtures for warm industrial environments to not only look at the stated wattage, but also at how the fixture performs at the actual ambient temperature at the installation location.<\/p>\n

What is the difference between ambient temperature and junction temperature?<\/h2>\n

Ambient temperature is the air temperature around the fixture. The junction temperature is the temperature at the exact point where the LED chip converts electricity into light, the heart of the chip itself. This distinction is crucial: the junction temperature is always higher than the ambient temperature, and it is precisely the junction temperature that determines how well and for how long an LED performs.<\/p>\n

The difference between these two temperatures is determined by the thermal resistance of the fixture. The better the heat is dissipated from the chip to the outside of the fixture, the smaller this difference is. A fixture with poor thermal design can, at an ambient temperature of 40\u00b0C, already reach a junction temperature of 100\u00b0C or more, with all the consequences that entails.<\/p>\n

Therefore, it is important for engineers and project managers to consider the maximum junction temperature (Tj max) and thermal resistance (Rth) when specifying a luminaire. These values provide a more reliable picture of actual performance than just ambient temperature alone.<\/p>\n

How does thermal management ensure stable light performance?<\/h2>\n

Thermal management is the set of measures that allow a luminaire to dissipate heat from the LED chip to the surroundings. Good thermal management keeps the junction temperature low, which directly contributes to stable light output, longer lifespan, and less maintenance. It is one of the most determining factors in the quality of an industrial LED luminaire.<\/p>\n

In practice, thermal management consists of a combination of elements:<\/p>\n