Efficiency of high-power LEDs relative to incandescents?

This may be something of a dumb question, but...

How does the efficiency of a high-powered LED (I'm thinking of 1000+ lumens here) compare to that of an incandescent light of similar output?

The reason I ask is that I have always believed LEDs to be highly efficient (this being their major advantage over incans, along with robustness and longer life), but it appears that the "power" LEDs still produce an awful lot of heat when driven hard.

So, does the efficiency advantage still hold true at high outputs, or does there come a point where a good incandescent bulb can produce more lumens per watt than an LED, and hence a longer runtime than the equivalent LED using the same battery capacity?

Cree XP-G runs at 139 Lumens per watt:

http://www.cree.com/press/press_detail.asp?i=1241094842732

Now this still means that less than a quarter of the energy is going into producing light, so yes it will still get hot - but there's no way you'll even get close to that with an incandescent bulb.

Typically a 100 watt incandescent light bulb makes around 1000 lumens. Some state right on the bulb or packaging what they are in lumens and you will see the answers vary from 900 something to 1100 something lumens.

I have seen LED flashlights that make 1000 out the front lumens run at 20 to 24 watts. And most of them don't hold the lumens output as they warm up. But at best 1000 lumens from 100 watts versus 1000 lumens from 20 watts for an LED the efficiency is 5 times better at those power levels. If you go with source lumens of the LED itself than you get about 7 to 1 at the 1000 lumen range.

the efficiency is up around 20 to 1, LED to incan when you keep it down in the 1 to 3 watt range. There have been many charts published on how LED efficiency is greatest when its driven well below its max power rating. Incandescents actually get a little bit better when you overdrive them as the resistance of the tungsten filament goes up but of course when it burns out then its a useless piece of glass envelope.

Incandescants are far less efficient. They don't have that pesky heat problem, though. You can insulate them from the host and (almost) never worry about the heat in a 100W+ setup. Just don't put your hand in front of it