I have had a basic understanding of LED lighting watts, lumens, and Kelvins for some time. I can usually figure out what lights I need in a given situation or use.
Now, I have a different problem. I have a small bathroom that the old incandescent lights made hotter (as in real temperature) after about 15-20 minutes. I switched to the least expensive non-dimmable LED lights I could find and it made it a lot better. However, they still noticeably heat the room more than normal after about 40 minutes. Does someone have, or have you seen a chart that will compare watts, lumens, Kelvins, and actual physical temperature?
**I’m currently using 3 GE 430 lumen, 5 watts, at 2700K.** (So called 40 watt equivalent) They are the standard screw in base with what feels like a ceramic coating that comes up about 1.5 inches above the screw thread. The bulb stays cool, but the coating at the base gets hot enough that you don’t want to touch it after about 10 minutes and begins to give off noticeable heat after about 30 minutes.
**I know all these lights will produce some heat**, but I would like to find something similar that does not heat up quite so much. Even with the bath fan running, you can feel the heat from these lights (they are in a light bar over the mirror) when you are in front of the mirror for very long.
In: Technology
The Watts (actual, not equivalent) of the bulb are the only thing that has any bearing on the heat the bulb gives off. The only real way to drop the heat would be to go to an even lower wattage LED, but that would provide less light as well.
A dimmer switch could accomplish the same thing as a lower Watt bulb, but would also make it give off less light.
The heating is expressed in watts. It is as simple as that. The color and lumens describe the spectral distribution of energy. But it all ends up as heat in the end. Three bulbs would emit 15 watts of heat. That is a very small amount and not likely to be perceptible. The most efficient lights are usually in the filament form, or a LED strip. Some bulbs like Ikea Solhetta can bump the efficiency marginally. You might cut the power to 11-12 watts for the same amount of light, which is not worth the effort, but might help with the lifetime of the bulbs if they burn out in enclosed space.
The smallest practical heater would be like 500 watts. A person would give off around 80 watts. You can feel the heatsink of the bulbs, but if you kept your hand on it, the small amount of heat would be easily whisked away. The part stays hot because it is very small and only touching the rarefied air. A conventional lightbulb also emits radiant heat, part of which goes through the glass and spreads out.
No chart is required. Simple physics will tell us that the total heat produced by a bulb, including absorbed light, will be exactly equal to the energy consumed by the bulb. That 5 watt bulb will produce 5 watts of heat, or 1/8th that of the incandescent bulb it replaces.
Color temperature refers to the color of the light in reference to the color produced by heating any material to that temperature. Heat something, a tungsten filament or anything else, to 2700 Kelvin and it will emit light mostly of that color.
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