HID is good for long time continuous operation
SON is good for flooding an area with light for the lowest cost possible (both in electricity and in lamp cost). The Orange light with minimum (but still usable) color rendering is ok for where a relaxed but still well lit ambience is required, or where the color rendering is not required whatsoever
MH is good for where better color rendering is requierd, with the expense of higher lamp cost and somewhat lower efficacy
Mercury is good for being the cheapest solution in lamp and gear cost, but is relatively inefficient and nowadays you are running into risk of lamp unavailability when it will be time to change the lamp. So it makes sense for lighting that is not switched on very often
In 230V-countries, MH and SON up to 250W are interchangeable in the same luminaires (except for self starting SON lamps). There is limited compatibility of MH lamps to SON gear also at 400W
The good light quality and unobtrusive light of both SON and MH, allows for good vision even without the light spread uniformity, to the extent where light spread uniformity becomes largely unimportant in many applications
Drawbacks of HID include high cost, and long restarting time in which the light cannot be switched back on when hot (for approx. 1 minute with SON, and much longer with MH)
Fluorescent (linear, PL and 2D) is good choice for ligthing that comes on instantly and can be switched a few times per day without big negative effects on lamp life
It provides good light quality, although lower than HID, but still very unobtrusive and allows good vision regardless of uniformity
Drawbacks of Fluorescent include inability to provide instant bright light in the cold, so it might only work well in the summer depending on your climate
Incandescent and Halogen provide good light and dont mind being switched many times, but are fairly inefficient
Incandescent is possibly the best choice for lighting controlled by a motion sensor, which comes on many times for short periods
Halogen provides better light, but to realise good lamp life, the lamp must stay on for some minimum time. So it makes sense over Incandescent in cases where the light stays on for a while if it is switched on
Like Mercury, Incandescent and Halogen may be good choices for lighting which is not switched on often (so does not accumulate to high energy use over a time period)
LED provides the widest choice of colored light, but for plain White light it provides the worst light quality of all light sources : The light is full of narrow band Blue light which is harmful for health at long exposure, inhibits night vision shortly after exposure (which is a problem if you are walking from the illuminated area into a dark area or trying to look into the dark area to see something), and provides quite poor color representation regardless of any CRI numbers
LED lighting could be used for :
1. To light up a place you walk through and away
2. As an accent light
This is true for both cheap and expensive LED lights. However, in other things like lamp life, correctness of claimed light output, the expensive LEDs are ok while the cheap LEDs tend to fall short on virtually all criteria
Additional Drawbacks that affect some LED luminaires are high glare and irrepairability (entire luminaire must go to trash if it EOLs)
For virtually all light sources, there are some options with electronic and some options with magnetic gear. Magnetic gear is generally more reliable. "No gear" is only applicable for Incandescent and Halogen, all other lamps do have gear, even if it is inside the lamp. However, if it is inside the lamp, then it does not complicate maintenance
Also, some light sources have common failure modes in which they short out the supply : Incandescent lamp EOL, some electronic gear failures, and so on. Consider that if this happens, your entire installation (that's on the same breaker) will go dark, not just the lamp that got a problem
For some applications, it makes a safety problem to pull line voltage (120V or 230V) supply to the light (e.g. deep garden landscape lighting, if not properly buried underground). In such cases it makes sense to drop the voltage to extra low voltage (12V or 24V) and use suitable lamps, which brings the choice down to Incandescent, Halogen, LED, or using a step up transformer at the luminaire for anything else
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