Halogen incandescent V Traditional incandescent

[Bob Hughes]

Hi all, this is not a question fot the pureists amongst you, but has anyone tried using Halogen incandescent instead of Traditional incandescent.

I understand that Halogen incandescent give out more heat than traditional which are being phased out (I know available still) so assuming a slightly lower wattage would be OK.

Has anyone worked this out for 40w replacement

[Alfred]

You have it backwards. The entire reason regular incandescent bulbs are being replaced by halogen is that halogen bulbs are more efficient, and thus generate less heat for the same amount of light. A 40W equivalent halogen will use less than 40W and will put out less heat but about the same amount of visible light as a traditional 40W incandescent. A true 40W halogen (not equivalent) will probably put out about the right amount of heat, though will still be biased more towards visible light than a traditional incandescent.

It's all about power. The reason, for instance, a 40W equivalent LED produces so little heat is that it actually uses about 5W of power. Most of it goes into the production of light rather than heat. Halogens are much less efficient than LEDs, but still slightly more efficient than traditional incandescent. The trick will be finding a halogen that actually uses 40W or slightly more and will fit in the lamp. The (potentially) good news is that if you do, the lamp will be brighter and a little less orange (good for something like a blue/white) with the same flow.

[Bob Hughes]

Thanks for the input all.

I was confused by info from the web that said more efficient on light and consequently less efficient on heat.

I will experiment if i can get hold of SES and SBC.

[VOXul]

So it seems there are conflicting stats here. Alfred says higher watt halogens match to lower wattage incandescent in terms of heat but itsy says that Mathmos supplies a 35w halogen for a lamp that takes a 40w incandescent.

I had converted an incandescent lamp over to a halogen bulb. It should take an almost extinct 35w E17 bulb. I found a 50w halogen that fit, after modification, but have been fearful of running it at full power as I thought the halogen would create a much higher heat output so I dim it.

Which theory is correct? Am I safe in running my lamp at a full 50w power on the halogen in order to match the heat output of the 35w incandescent?

[Alfred]

50W is likely far too much to run the lamp for long, but as long as the bulb isn't touching the globe, I'd give it a try.

It's possible that differences in the shape of halogen bulbs or how they dissipate heat has a greater effect than their efficiency. Or, it could be that the greater "efficiency" of halogen bulbs is just due to the spectrum they produce. Since the filament itself burns hotter (doesn't mean it radiates more heat – just that the surface temperature is higher), they produce less red and more green light, which will appear brighter. I wasn't able to find definitive information on exactly how the heat output of halogen compares to incandescent, at least none that convinced me they weren't confusing a higher filament temperature with the amount of radiated heat.

Regardless, if LL is using 35W bulbs, I'd also give those a try.

[Bob Hughes]

Thanks agin for the input, its appreciated

Bob

[Mick P]

Just reviving this because I've been running a 35w halogen very successfully in my Crestworth Astro. However, it blew after very little use, maybe 50 hours, certainly under 100, all in bursts of about 3 hours max. 

Has anyone else found this? Just wondering if halogens don't appreciate being run in such a hot environment.  

[Elias]

Had the same experience with multiple halogen bulbs from Mathmos. Some go out after a few minutes while others just work.

Had the same thing happen to incandescent bulbs a few times but mostly in my Crestworth cosmos so it might have something to do with the lamp rather than the bulb.

[Mick P]

Just to clarify, mine was a bulb bought locally, not from Mathmos, but it's interesting to hear that you've also had patchy longevity.