Hi Everyone, I wonder if anyone has experience of Summit collapsible Cob lanterns? I have a 6 man tunnel tent and need to light up the living area and the porch area. I did order two 9w Summit cob lamps but they sent two 3w cob lamps! which are supposed to emit 300 lumens each. How many lumen would I need to light these areas, does anyone have a clue please?
Roughly speaking a 300 lumen output is equivalent to a 30W incandescent light bulb if that helps. So they'll light those areas enough to move around without bumping into things but not enough to read by.
they used to say that a compact florescent bulb of 11W was the equivalent of an old 60 Watt bulb and that would emit 600-800 lumens and the equivalent LED would be 7-9 watts
so a 3 watt LED may emit 300 lumens but in old money it is equivalent to a very dim 30W Incandescent bulb
our kitchen light unit has three 8.6W LED bulbs said to be a 60w equivalent and they emit around 800 lumens per bulb and are 3600k so all three bulbs are equivalent to one 150-200 watt Incandescent bulb
the other thing to watch with LED bulbs is the kelvin scale of the bulb. 3000-4000k was the scale for the old Incandescent bulbs so warm orange. Some new LED bulbs are 6000-7000k so a very cold harsh blue light
A very much simplified method is to calculate the lumen levels by dividing lumen output of lamps by floor area in square metres and multiply by a utilisation factor (UF) probably a factor of 0.2 0r 0.3.
The UF is the proportion of light emitted reaching the working plane, in your case the floor.
Natural sunlight on a bright day is 5000 to 6500K. The old incandescent lamps were actually closer to orange but we became used to seeing them and therefore the orange light became the norm. The natural light colouration certainly helps to keep me awake when I'm working in the office, but for relaxing the orange colouration is more restful and helps prior to sleep time.
------------- 'A sure cure for sea-sickness is to sit under a tree'