In article ,
The Natural Philosopher wrote:
Average lightbulb is around 1-2%.efficient. Halogen being at the upper
end, and cheapo dim long lifers at the other.

However the eye perceives brightness logarithmically. To be twice as
brght probably means 4-10 times the power. That makes efficiencty
variations of even 2:1 pretty insignifiocant.

I recently changed the bulbs in my car headlights. Same size. The
difference in light output was *dramatic*.

I couldn't give a toss about the theory, but the practice means a great
deal.

--
*If love is blind, why is lingerie so popular? *

Dave Plowman London SW 12
RIP Acorn