You simply cannot buy a better tankless water heater. Each of the tankless water heaters on our shortlist is a top choice in its price/performance bracket. However, the overall winner of our âBest of the Bestâ award is definitely the Stiebel Eltron Tempra 24 Plus.
The difference between the lux and the lumen is that the lux takes into account the area over which the luminous flux is spread. 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 lux.
How to convert luminous flux in lumens (lm) to illuminance in lux (lx). You can calculate lux from lumens and surface area. Lux and lumen units represent different quantities, so you can't convert lumens to lux. 1  Lumens to lux calculation with area in square feet. 2  Lumens to lux calculation with area in square meters. The illuminance E v in lux (lx) is equal to the luminous flux Ï V in lumens (lm) divided by the surface area A in square meters (m 2): E v(lx) = Ï V(lm) / A (m 2). For a spherical light source, the area A is equal to 4 times pi times the squared sphere radius: