Originally posted by falconeye Ben, you seem to be more knowledgeable about all this than me, so let me ask you a question:
What is a good replacement for an incandescent bulb which is meant to only be used for a couple of seconds, like a doorstep lamp?
I do have a problem with CFLs (power on slowly) and AFAIK halogen bulbs are soon to be phased out as well.
I tried a "Liquid LED" which replaces incandescent bulbs at only 10% of power consumption (only 50% of CFLs and over time, cheaper than CFLs) and is instant on. But I didn't like its light. Must have a bad CRI...
liquid LED ::: Die Original-Energiesparlampe aus dem Bayer-Kreuz in Leverkusen That's a hard to solve problem at the moment. For these short but often repeated cycles, I still think, the good old incandescent bulb is your best bet. Very good bulbs are the shock-resistant types, which have a very long life expectancy and are still available:
Glühlampen mit Stoßfestigkeit von Osram bei Westfalia Versand Deutschland
Halogen bulbs, in my experience have a very short lifetime, if switched frequently. There are some CFLs advertised especially for this purpose, but they work best, if any single switch cycle is at least 90s-120s long, which might be unnecessary. Also, I do really not know, how long such a CFL will survive in real use. I would in any case try an Osram modell, especially made for staircases:
OSRAM DULUX® EL FACILITY - OSRAM - Voltimum.de
This modell at least looks promising, but I really don't know, how long it would survive, if power cycles are very short. In a typical staircase the power-on cycle would ly within the minimum time frame I suggested or even be a bit longer (depending on the number of floors). So it would be unnecessarily long for the door of a standard family home.
Longevity is probably the reason, why Osram also sells a servo CFL for continous lighting during the dark hours:
OSRAM|Professionals|Allgemeinbeleuchtung|Kompaktleuchtstofflampen|Produkte|Intelligente Kompaktleuchtstofflampen|OSRAM DULUX INTELLIGENT SENSOR|index - But a warm white colour will also leave a lot to be desired in terms of CRI. But that contradicts the energy saving efforts somewhat, to have it burn all night…
I would try one of the currently new 3W LED-bulbs (Osram or Philips, not sure), which are available in warm or cool white. But they seem to have a narrow beam and won't illuminate an whole front door, unless you combine several. I am currently trying LED lights in my home, but I must say, I find the light also quite unpleasant, or too dim, to be really useful yet. I have not tried the led bulbs which illuminate the full 360 degs, yet. Just the rated wattage seems to be way too low to be useful - and the water cooled variety you have already tried.
Ben