Would a 70w halogen bulb produce less heat than 60w normal bulb?

[cmb]

How do you think the filament in a halogen source achieves its different colour temperature, if it is at the same temperature as the one in a standard bulb?

No-one has said it would be at the same temperature. Quite the opposite.

But it might be as 'hot' as a filament in a standard bulb, that is; same J, different K.

You seem to be labouring under the impression that the filaments would be the same size. Just figure that the incandescent one is twice the size of the halogen one... same heat flux, but arising from twice the differential temperature!...

 

[Vanadium 50]

CMB, this is much simpler than you are trying to make it, partly because many of your "facts" are not.

Halogens and ordinary incandescents operate at the same filament temperatures, around 3300K.

70W goes into the bulb. Energy is conserved, so what is not converted to light becomes heat. The fraction of energy converted to light is between 2 and 2.5% for both ordinary and halogen incandescent bulbs. So the 70W bulb produces something like 15-18% more heat than the fixture is designed to handle. Full stop.

Your suggestion that it is safe to exceed the posted limit because surely someone somewhere put in a safety margin is irresponsible and dangerous.

 

[AlephZero]

Most of #13 - #31 seems to be a (fairly hypothetical) discussion of the normal operation of the lamps.

Safety ratings are about abnormal situations, whether accidental or "deliberate but misguided". As V50 implied, in a worst case situation (e.g. all cooling airflow around the bub is blocked off) the only thing that matters is the total heat output from the lamp.

 

[cmb]

CMB, this is much simpler than you are trying to make it, partly because many of your "facts" are not.

Halogens and ordinary incandescents operate at the same filament temperatures, around 3300K.

Really?

(Why have you singled me out for that comment, when I was neither the first nor the last to make it?)

Your suggestion that it is safe to exceed the posted limit because surely someone somewhere put in a safety margin is irresponsible and dangerous.

I did not make that association '..because..'. That is falsely attributing something to me that I did not say. I made it clear that a '60W' rating is making it clear that a '100W' bulb is unsuitable, that being the next power rating up, and that the consumer should be cautious over using 'similar' ratings in the new technology but that it is unlikely to make much difference.

Please quote from my text where I said "...it is safe, because there is margin...", or otherwise acknowledge your misreading of my posts.

In fact, to make it easier for you, please quote anywhere where I have used the word 'safe'.

 

[cmb]

Most of #13 - #31 seems to be a (fairly hypothetical) discussion of the normal operation of the lamps.

Generally, that is so, but it still presents a real and present issue because, e.g., in the UK light fittings still all generally say either 'use 60W bulb' or 'use 100W bulb'. The problem is that you can no longer buy bulbs with those power ratings. The nearest equivalents to 60W, for example, are 70W (equivalent to '95W' worth of incandescent) or 35W (equiv to 45W). So, for an equivalent application, the former is technically too much power, the latter is typically too dark for the application.

So an unsupported comment like Studiot's, from which the #13-#31 series ran, [that 25W halogen should not be put in 60W regular fitting] is unhelpful.

 

[cmb]

Halogens and ordinary incandescents operate at the same filament temperatures, around 3300K.

Dan MacIsaac, Gary Kanner, and Graydon Anderson. "Basic Physics of the Incandescent Lamp (Lightbulb). The Physics Teacher. Vol. 37 no. 10 (December 1999): 520-525:

It is extremely difficult to maintain an average temperature [of ordinary incandescents] higher than about 2900 K

OSRAM Sylvania:

The tungsten-halogen light is similar to conventional non-halogen incandescent light in that it employs a tungsten filament in a gas-filled, light-transmitting envelope and emits the same type of light. The major differences are that a trace of halogen vapor (e.g., iodine or bromine) is added to the inert fill gas, the gas pressure (7-8 ATM) and bulb temperature (250° C to 600° C) are much higher than in non-halogen lamps, and the bulb is made of fused quartz (silica, SiO2), high-silica glass or aluminosilicate “hard” glass to withstand the high operating pressures and temperatures. Lastly, there is a higher color temperature, 2800° K to 3400° K for standard halogen product.

http://www.sylvania.com/ConsumerProducts/AutomotiveLighting/Products/Halogen/HowHalogenWorks.htm

 

[Vanadium 50]

The OP is asking for us to OK something that is potentially unsafe. The only recommendation we can give to the OP is "don't do that."

Manufacturers of halogen bulbs that are designed to serve as a replacement for standard incandescent bulbs design those bulbs so that they can be used in general lighting service lamp sockets of the same wattage ratings as the original standard incandescent bulbs. No manufacturer would stand by the safety of putting a 70 watt halogen bulb in a lamp rated for a 60 watt bulb.

If anything, the OP should consider replacing a 60 watt standard incandescent with a halogen bulb of a slightly lower wattage (but same amount of light), or with a much lower wattage LED or compact fluorescent bulb.

V50, for the mentors.