Some quick research when I was trying to find out if IR led strips are more efficient the conventional IR bulbs.
LED strip input voltage 4.8w/m
24 watts for 5 meters.
850nm spectrum – 940nm
Infrared bulbs are from 780nm-1400nm
Typical LED efficiency is 72% in red, 98% in red-orange, 93% in green.
Magical new IR LED (2012) is 72% efficient.
Typical (bulb) heaters are “up to” 86% efficient.
Water absorbs 3000nm best.
LED’s don’t get close to that. I’d say that puts the last nail in this coffin.
Black-body energy is a lower frequency if the bulb is hotter.
We can probably produce IR at a pretty high efficiency, compared to other parts of the spectrum.
Go with a bulb.