LED's of Similar Output to T12

[kwired]

Heatsink is needed, because CPU can't function if it is allowed to get hot enough to let radiant heat get rid of most of 15W.

Heatsink can get no cooler than ambient and LEDs seriously struggle in unairconditioned high ceilings.

A 15W LED requires quite a heatsink, because the heatsink needs to operate at low delta T and virtually no dissipation by radiant power.

I'm not trying to say LED's don't need thermal management. Just saying what seems like a small wattage can still be a pretty high temperature if concentrated in a small enough area. The soldering iron was just one example where we have a relatively small wattage but a pretty high temperature.