Remember folks, ALL flouros contain mercury. A flourescent light or tube works by passing electricity through mercury vapour. It emits UV light, that strikes the phosphor coating on the tube interior. This converts the UV to visible light.
Leds are today not as effecient as the best Flouro tubes, see
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Note, new prototype LEDs promise better than flouro effeciency though.
The most effecient artificial lightsource we have is the good old fashioned low pressure sodium lamp, at a whopping 200 lumens/watt. It is excellent for astronomy too, as the 2 sodium lines are easily blocked by all LPR and nebula filters. If all our cities were lit exclusively by them, though we would have to put up with everything in yellow monochrome, we could use filters that reject just the yellow sodium lines and clear to all else, and have skies as dark as Siding Spring Observatory, and have much lower power consumption and greenhouse gas emissions to boot.
Note. With flouros, coloured tubes are also very efficient. EG a red tube has phosphor that emits only red light, whereas putting a red filter over a white light means the other colours are still produced but blocked.
My design for a mega long lasting flouro light source is to not heat the electrodes at each end, rather use an efficient step up power source to supply sufficient voltage to get a discharge happening while cold. That is, make them as cold cathode light sources.
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Quote:
Cold cathode fluorescent tubes operate at a much higher voltage and lower current than conventional fluorescent lamps. The higher voltage overcomes the need to heat the tube while the lower arc current greatly extends the life of the discharge electrodes.
Dispensing with the wasteful heated electrodes allows high efficiency to be achieved in a small lamp. Cold cathode lamps are typically ten to 30 percent more efficient than a comparable hot cathode fluorescent lamp.
Cold cathode lights have a life expectancy more than twice that of typical compact fluorescent lamps and do not suffer accelerated degradation with variations in supply voltage.
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Laser diodes may bright about the most effecient lighting.
This mob managed a staggering 71% Electrical-to-Optical Power Conversion Efficiency
