Replacing 1 LED Lamp with 2

[Martin109]

I'm replacing a fitting which has 1 LED lamp rated at 13W, and the new fitting requires 2 LED lamps (max 10W each), and I want to achieve roughly the same light output.  I can't decide whether the answer to this is 2 x 7.5W bulbs, or 2 x 13W (which would be too much for the fitting anyway).  Logic tells me 2 x 7.5W, but I'm not sure and would like confirmation from the physicists on here!

[Diver300]

There is a big variation in light output for the same power from different manufacturers. However a big variation, like 2 times the light, would not necessarily be noticeable unless it is in comparison with something else.

I would say that 2 x 7.5 W will be a good start. The variation of spread of light due to the different fitting and different bulbs and possibly a different colour from different bulbs will be more noticeable than the change from 13 W to 15 W.

[Pickled Onion]

You can't really use wattage, it's more an indicator of how much heat it generates than how much light. So it's useful in terms of the maximum you can use in a fitting or to work out how much electricity it uses.

If you know how many lumens the old bulb produces you can compare that with the replacements.

[Martin109]

Thanks for those useful tips!