How hot do LED headlight bulbs get?

**Photo courtesy of Tayla Jones, Darrin Chapman**

Do LED headlight bulbs run hotter than halogen bulbs?

This is a question we hear a lot and today I did some testing with a very accurate thermal heat sensor to see the difference in heat after 30 minutes of usage from a standard 55w halogen bulb and 4 of the newest LED headlight bulbs to hit the market!

55w Halogen: average temp 150 degrees
Oracle 4000LM: average temp 184 degrees 20% hotter than halogen
GTR Lighting GEN 3: average temp 171 degrees 15% hotter than halogen
Putco Silver-Lux: temp as high as 143, average temp 116
Street Glow XHP: average temp 93 degrees

We tested the Street Glow XHP Series, the Putco Silver-Lux, the new Oracle 4000LM bulbs, and the new GTR Lighting GEN 3 Ultra LED Headlight Bulbs.
The results are SURPRISING!

Halogen Headlight Bulbs: 155 degrees on the back side and 161 degrees on the front side
First up we tested the halogen bulb. A run of the mill Philips 55w incandescent light bulb found in millions of cars and trucks around the country. This set our benchmark. On the back side of the bulb there is a plastic connector where the two wires connect. After 30 minutes of use this bulb got to a whopping 155 degrees Fahrenheit! This was surprising due to the fact that normally when handling a bulb by the plastic portion it’s not that hot… But to see these types of temperatures really challenged the view of what the material a headlight is capable of withstanding are. Clearly if it can withstand 155 degrees it is made of some pretty hefty material!

The rear of the bulb saw temperatures from low 140’s up to high 150’s after running for 30 minutes.

Here you can see the laser sensor aimed at the entire back of the bulb to get the most accurate and complete reading.

The front of the headlight housing affected by the glass bulb and the filament was no surprise. We picked up temperatures as low as 153 degrees Feranheight all the way to 161 degrees Fahrenheit. The important thing to remember here is if this is the temperature the headlight housing was designed for, anything less than this will surely be safe, and anything a little hotter than this will still likely fall into it’s acceptable range of heat capability.

Here you can see one spot in the reflector pattern reading at 156 degrees. Depending on where we measured at it was a different temp.

The max temp measured was 161.3 degrees.

55w Halogen: average temp 150 degrees
Oracle 4000LM: average temp 184 degrees 20% hotter than halogen
GTR Lighting GEN 3: average temp 171 degrees 15% hotter than halogen
Putco Silver-Lux: temp as high as 143, average temp 116
Street Glow XHP: average temp 93 degrees

Oracle 4000 Lumen LED Headlight Bulbs: 189 degrees on the back side and 91 degrees on the front side
In 2016 Oracle Lighting introduced a new fanless LED headlight bulb boasting 4,000 Lumen per bulb. This bulb is not the brightest on the market by any stretch of the imagination but it does have it’s benefits. It looks nice, uses real Philips LEDs and is somewhat adjustable. But it is lacking in original design and actual usable light output. We found that the back side was significantly hotter than the halogen bulb coming in at between 179 and 189 degrees Fahrenheit. Up until recently LED bulbs used a fan inside the heat sink so to see this bulb reach these temperatures wasn’t too surprising since it didn’t use a fan.

The Oracle 4000 Lumen LED bulbs reached temps of between 179 degrees – 189 degrees after running for 30 minutes.

Having the bulb energized for 30 minutes allowed us to experience the max heat levels, and when we looked at the temperature of the front of the housing reflector area we measured the entire thing and found temps from between 82 and Fahrenheit. This is significantly lower heat than the halogen counterpart which reached 161 degrees.

After 30 minutes of testing the Oracle bulbs reached 91 degrees. Significantly lower than the 55w halogen.

GTR Lighting GEN 3 Ultra Series LED Headlight Bulbs: 207 degrees on the back side and 88 degrees on the front side
The GTR Lighting GEN 3 Ultra Series LED headlight bulbs released in December of 2016 are easily the brightest LED bulb on the planet. Boasting upwards of 350% increase in light when compared to the original halogen bulbs, and 40% – 200% brighter than the competitive LED bulbs. Do your research on these, they are impressive!

On the heatsink, we measured temperatures ranging from 135 degrees up to 207 degrees Fahrenheit after being turned on for half an hour. This wide range of heat is indicative that the heat sink design is actually working! GTR Lighting’s heat sink design is based around the idea of convection plate cooling where you’ll see a cooler area across from a warmer area thus drawing air over the heat sink plates naturally: This was surprising due to the fact that normally when handling a bulb by the plastic portion it’s not that hot… But to see these types of temperatures really challenged the view of what the material a headlight is capable of withstanding are.

There’s a massive 70-degree difference from one side of the heat sink to the other which indicates that the convection plate technology is actually working!

The GEN 3 bulbs from GTR Lighting showed us the hottest heat sink temperature of any we tested but the reality is it’s not that much hotter than the halogen bulb, or the other LED bulbs. Yes it’s the biggest temp number, but not by much. And on the front side of the headlight where the actual light bulb is, the temperatures were lower than almost anything we tested. This combination of high heat sink temperature, low bulb temperature, and the brightest measurable light output on the planet makes it for a pretty great option.here the two wires connect. After 30 minutes of use this bulb got to a whopping 155 degrees Fahrenheit! This was surprising due to the fact that normally when handling a bulb by the plastic portion it’s not that hot… But to see these types of temperatures really challenged the view of what the material a headlight is capable of withstanding are.

After 30 minutes of operation we recorded temperatures on the GTR Lighting GEN 3 LED bulb heat sink as low as 135 degrees.

Temperatures on the other side of the heat sink actually measured as high as 207 degrees.

Like all LED bulbs, when measuring the temperature of the actual bulb portion that emits light, inside the headlight housing, the temperature was drastically less than the OEM halogen bulbs. The original 55w light bulbs were around 160 degrees, and the GTR Lighting GEN 3 LED itself only reached a max temperature of 88.9 degrees Fahrenheit.

The front of the housing was significantly less hot than the halogen version when running the GTR Lighting GEN 3 Ultra Series LED Headlight bulb for 30 minutes.

Putco Silver-Lux LED Headlight Bulbs: 144 degrees on the back side and 77 degrees on the front side
The Putco Silver-Lux LED headlight bulbs are one of many options on the market today featuring a braided copper heat sink crimped onto the base of the LED bulb to release heat away from the bulb. This new style of heat sink design is slightly better at cooling off the bulb than the non-fan heat sink style, but the drawback of this design is it’s susceptibility to corrosion if exposed to the elements. The Putco Silverlux with the braided heat sink saw temperatures on the back ranging from 90 degrees to 144 degrees Fahrenheit which indicates this style of heatsink is effective.

The lowest recorded temperature reading on the heat sink of the Putco Silver-Lux LED headlight bulb was 90 degrees at the end of the flexible portion. However, as you move closer to the bulb the temps reach upwards of 143 degrees.

The hottest part of the heat sink on the back side of the Putco Silver-Lux LED bulb reached 143 degrees. Significantly lower temperature than the halogen bulb, and of most LED headlight bulbs.

To get these bulbs to operating temperature we had them fired up and installed inside a headlight housing for 30 minutes then used the temp sensor to find various points on the bulb to analyze. It is important in order to get good usable data to examine more than just one part of the product. So, on the front of the headlight, inside the headlight bulb and reflector we saw temperatures ranging from 75 – 77 degrees Fahrenheit.

The Putco Silver-Lux LED headlight bulb doesn’t run very hot which is a big benefit for those concerned about heat. But the downfall to this bulb is it isn’t even close to being the best/brightest on the market. One way to reduce the heat of your electronic device is to lower it’s power.

Street Glow XHP Series LED Headlight Bulbs with Fan: 113 degrees on the back side and 76 degrees on the front side
Until recently, the industry standard on high power LED headlight bulbs cooling mechanism was an oversized aluminum heat sink hollowed out to hold a high-RPM fan inside. The most prominent critique of this method is that to require a fan as part of the construction is bulky, failure-prone, and more expensive to manufacture so more and more LED bulb companies are trying to get away from this method. However, the truth is that it works. It may be a large heat sink that won’t fit most applications, but it is by far the least hot LED headlight bulb we tested here.

We tested the Street Glow XHP Series, the Putco Silver-Lux, the new Oracle 4000LM bulbs, and the new GTR Lighting GEN 3 Ultra LED Headlight Bulbs.
The results are SURPRISING!

Depending on what area of the heat-sink we tested we saw massive differences in heat on the Street Glow XHP LED headlight bulb. Nearest the fan we recorded temperatures of 71 degrees Fahrenheit. The further away from the blowing air the heat jumped large amounts, up to 113 degrees. Now, 113 degrees on the back side of a high power LED headlight bulb is pretty dang good! But the tradeoff is that the Street Glow XHP is far from the best performing LED bulb we tested in terms of usable brightness, and appropriate beam patterns. What good is an effective cooling mechanism when the bulb doesn’t perform in the first place?

The lowest recorded temperature we could find on the LED bulb heat-sink was 71 degrees after being run for 30 minutes straight.

When measuring the Street Glow LED bulb fan-based heat sink device, the hottest portion was around 113 degrees. This was much cooler than most LED headlight bulbs in its class.

When looking at the front of the headlight housing we found again some very low heat ratings. The original halogen bulbs measured a wildly hot 161 degrees on the front of the headlight, where the new LED bulb which is brighter, measured no more than 76 degrees Fahrenheit total. This is a massive benefit to the health of the headlight, proves these bulbs will work in cheaper aftermarket headlights with less trouble, and a great indicator that we’re moving in the right direction with this technology in terms of efficiency – using more of the energy to produce light, and less in wasted heat!

Even after running the bulb for 30 minutes straight, it still produced half of the heat that the original halogen bulb did. We found temperatures within the reflector bowl around the 73 degree mark, all the way up to 76 degrees.

Conclusion (TL;DR):

#1: The original halogen bulbs run REALLY REALLY HOT!
#2: The fan-based heat sink design is still the version that cools the best, but it’s other downfalls outweigh it’s usefulness.
#3: The brightest LED bulbs are proven to create the most heat.
#4: Even on the LED bulbs that create the most heat, they are still not hot enough to damage anything in/on/around the headlight housing.
#5: LED Tech is evolving rapidly and it’s fun to see all the changes in the last year!

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