Hot Light Fixtures and Cold Air

We’re entering a bit of a new world with LEDs. The lamps are different, how they perform in fixtures is different, how they’re controlled is different and the end result, how the light looks, is different. One big change is that with intelligent lamps, such as LIFX and Phillips Hue, control can now be in the lamp itself. Instead of a dimmer dimming all of the lights on a circuit, we can now control each lamp individually. AND, not only can we dim each one but we can change its color temperature (from very warm to very cool) and even change its color from red to green to yellow to blue to just about any of millions of colors. 

This comes with a bit of a catch though – the electronics that allow this can be sensitive to heat. So, we needed to find out how these new lamps perform in a couple of different fixtures.

So, with some help from Mike at Krause Electric, I ran some very quick tests.

We tested four lamps (GE Incandescent, Phillips 5w (50w equivalent, non-intelligent) Warm Dim LED, Phillips Hue White & Color Ambiance (intelligent) LED, and LIFX GU10 multi-color (intelligent) LED), in two fixtures (Halo H36TAT, Halo H38ICAT) with two trims (Standard, Wet). The test rig may not look professional… But it worked. Below is the H38ICAT.

B1200LEDTest 100

This was not a comprehensive test of any sort. It was primarily to determine the approximate heat performance of the two Halo fixtures with different types of lamps.

Generally the lamps were allowed to burn for one hour by which time most had reached about their maximum temp. We took several readings to know when the temps had stabilized and were no longer increasing. 

Lux measurements were taken w/ a Sekonic L-478DR placed on the floor 3’ directly in front of the lamp. I did not use Lumens as this requires massively more effort (or massively more expensive equipment) to measure accurately since it requires measuring light output throughout the range in order to calculate total light output. It’s important to know that a wider beam lamp may have a lower lux measurement but actually put out considerably more lumens. This is possible even with identical beam widths as one lamp may concentrate its light in the center while another has a much more even light through its beam.

Internal ambient air temps were measured with a Thermoworks Thermapen. Surface temps were measured with a Thermoworks IRK-2

A few of the results:


The H38ICAT interior and exterior remained considerably cooler than the H36TAT. However, the lamp itself (measured at the hottest spot found) showed less variation and was only about 20° cooler in the H38ICAT.

Wet (sealed) vs Std trim made surprisingly little difference. This may have been due to using bare fixtures. Both trims were fully set against the housing though so the results in actual use should be similar.


Hue vs LIFX

We’ve used a variety of LIFX, Hue and other lamps and fixtures in our current house for some time as a test. 

  • LIFX are brighter than Hue and LIFX appear to have a better CRI.
  • LIFX have much better and deeper colors. They use a true Red, Green and Blue system. Hue’s colors are somewhat more pastel. Hue cannot produce Yellow or Green and Blue is closer to lavender.
  • Hue has more reliable connectivity though several people have reported that if you have a robust enough WiFi network that LIFX does just as well.
  • Personally I like the LIFX app better but LIFX does not have a driver for Control 4 so we will likely use a lot more Hue than LIFX just based on the lack of a Control 4 driver for LIFX.


Color Temp

In determining which color temp to use (assuming higher watts = higher heat) I found surprisingly more difference in lux produced and watts used for various color temps than I expected. Hue does not appear to allow selection of specific color temps so I was not able to replicate this for Hue.



In the end we learned a few things.

  • The H36TAT fixture does not dissipate heat as well as the H38ICAT.
  • Standard and Wet trims do not appear to affect heat dissipation very much.
  • LIFX lamps produce the brightest light at 3000°K.
  • Both LIFX and Hue appear much less efficient from a Lux/Watt standpoint than at least one standard LED lamp and likely less efficient than most.
  • Both LIFX and Hue appear most efficient (produce more Lux / Watt) at 100% brightness and less efficient when dimmed.

For some more interesting info:

In other news… Yep, it’s cold outside. -29°f this morning. It can sting a bit to breath.

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A squirrel made a home in the crab apple tree outside one of our windows. B1200Winter02 101