Why are LED lights warm

That's why LED lamps and recessed spotlights get so hot anyway

LED lamps have a high efficiency compared to conventional light sources. Nevertheless, some LED lamps get very warm in certain installation situations. GU10 lamps and recessed spotlights in particular often generate a lot of heat. Here you can find out why some LED lamps emit a lot of heat and what you have to pay attention to.

Table of Contents

Heat generation from LED lamps

The LED technology has become significantly more efficient compared to the old incandescent and halogen lamps. You couldn't touch the old light sources when they were switched on without burning yourself. Due to the high efficiency of the LED lamps, one could think that they hardly produce any waste heat. Unfortunately, this is a pipe dream, because even with the latest LED technology, a certain amount of waste heat is still generated.

Heat dissipation from incandescent lamp and LED

The heat generated by LED lamps is significantly lower than that of the old incandescent lamp. Incandescent lamps only generate around 5% light from the energy fed in, the remaining 95% is converted into heat. It looks much better with current LED lamps. Here around 40% of the energy used is converted into visible light and just 60% in heat.

The percentage values ​​show the difference in heat development between the two lighting technologies. It becomes even clearer when comparing two equally bright light sources:

  • 60W incandescent lamp with 730 lm
  • 6W LED light source with 730 lm

The incandescent lamp converts 95% of the energy used into heat. The LED light source achieves an efficiency of 35% and converts 65% of the energy used into heat.

Example: Calculate heat emission

Incandescent lamp: 60W 0.95 (95%) = 57W heat output

LED: 6W 0.65 (65%) = 3.9W heat output

The heat loss from the incandescent lamp is almost 15 times as high as that from the LED.

The LED filament lamps from Philips have a very good efficiency with low heat loss. You can find them here on Amazon.

Do LEDs generate infrared heat?

In the previous example, the incandescent lamp 57W generates heat loss. This is emitted to the environment in the form of invisible infrared radiation. As a result, the lamp glass heats up so much that you would burn yourself immediately if you touch it. LED lamps do not generate any infrared radiation. That's why you can touch bright LED light sources without getting burned. But where is the waste heat?

Most of the 3.9W heat loss from the example is generated in the light-emitting diode and a small proportion in the LED driver. The LED is a semiconductor. Its heat loss is not radiated by itself, but has to be dissipated using a suitable cooling solution. Otherwise the LED would die of heat death. If the operating temperature is too high, the service life of the lamp also decreases.

LED lamps also give off heat

LED lights and bulbs also generate a certain amount of heat. However, this is significantly lower than with the old light sources. In addition, the power loss is not radiated in the form of infrared heat, but has to be dissipated from the lamp via a heat sink.

The LED filament lamps from Philips have a very good efficiency with low heat loss.
You can find these here in different versions on Amazon.

How big is the LED heat emission?

LED lamps and light sources can get different warmth. This mainly depends on the following points:

  • Light output
  • Efficiency
  • size
  • Installation location

In the case of low-power lamps, the waste heat is usually so low that it can easily be dissipated into the environment. Naturally, brighter lamps with a higher luminous flux also generate more power loss. Good integrated cooling of the LED is all the more important here. A high efficiency of the LED lamp ensures a good ratio between light output and power loss.

The size of the LED light source also has an indirect influence on the development of heat. In small light sources there is less space for heat sinks, which is why they generally get warmer. How well the heat loss can be dissipated into the environment depends on the installation location of the lamp.

Retrofit vs LED luminaire

With the retrofit LED lamps, the old lamps can be easily replaced. The larger the design, the easier it is to dissipate the heat loss. The heat development with E27 lamps is therefore very low. Retrofit lamps for G4 or G9 pin bases, on the other hand, have a very small design. There is hardly any space left for a sufficient heat sink.

Despite the LED technology, these small lamps sometimes get very hot and there is a risk of burns if they are touched. In contrast, the heat generation is at real LED lights are less of a problem. Here the LEDs are integrated into the luminaire right from the start. The LED and the luminaire form a unit, which enables a better cooling concept to be implemented.

The heat development depends on the design

Small illuminants become warmer in practice due to the poorer cooling options.

Heat generation from LED spots and recessed spotlights

The heat development with LED recessed spotlights or spots can be problematic under certain circumstances. Recessed spotlights are embedded in the ceiling, for example, and can primarily give off their waste heat downwards. A good metal construction of the beam, as with these ceiling spots from Brandson, can guarantee this.

In order to keep the heat development of the LED spotlights as low as possible, the number of spotlights can be increased and the power per spotlight can be reduced. Instead of 5 spots with 800 lumens each, 8 spots each 500 lumens can be installed for the same brightness. This reduces the heat development in each individual radiator.

In order to further reduce the heat emission in the heater, 12V low-voltage spots can be used. These usually have a lower heat emission than the 230V variants. In a low-voltage recessed spotlight, there is only power loss in the LED and in the driver. The heat loss from the power supply unit does not occur in the spotlight, but in the separate LED transformer.

Heat development from GU10 lamps

LED GU10 lamps are a classic replacement solution for old GU10 halogen lamps. The heat development depends heavily on the installation situation. If the GU10 LED is used in a spotlight without lamp glass, the waste heat can easily be radiated into the environment. When the light source is used in a lamp glass or a built-in spotlight, the heat development is usually significantly higher.

An even higher heat emission tends to occur when using 230V GU10 lamps due to the integrated power supply unit. Especially with hanging lamps, the heat loss can only be transferred to the socket via the base. If the socket is in a recessed spotlight, the result is often a high operating temperature with a reduced service life.

Are GU10 lamps suitable?

The heat development of GU10 LEDs with high light output and unfavorable installation situation can be problematic. Real LED spotlights are a good alternative here thanks to the better cooling concept.

Conclusion on heat development

LED lamps without heat development remain a dream 🙂 After all, the heat loss is very low compared to the old light sources. The heat development depends heavily on the installation location of the lamp. In order to further reduce the heat emission, you should ensure that the LED lamp is highly efficient.