numpty question about max light wattage

[rotherdrummer]

so is it standard practice to assume the 25w max is referring to incandescent bulbs only? if so, isn't that quite low? i'm by no means an expert, but we've bought the 5-bulb pendant, this one to be specific, to hang over a large dining table in a kitchen extension. if i was to assume the 25w is for incandescent bulbs, that would mean i could only fit 5 x 4w LED bulbs ....which seems very low to me?!

 

[Harry Bloomfield]

so is it standard practice to assume the 25w max is referring to incandescent bulbs only? if so, isn't that quite low? i'm by no means an expert, but we've bought the 5-bulb pendant, this one to be specific, to hang over a large dining table in a kitchen extension. if i was to assume the 25w is for incandescent bulbs, that would mean i could only fit 5 x 4w LED bulbs ....which seems very low to me?!

Which suggests you don't have much experience of how much more light you get from LED, compared to tungsten lamps. I use 2.5w LED lamps as my go to for many areas. I have just two 8w LED fittings in my kitchen/diner.

Quality of light output does vary with the type of fitting, but the one you linked to is a quite efficient design I would suggest 2.5w LED will be perfectly adequate in those.

 

[rotherdrummer]

according to this table, 5 x 4w LED bulbs will give me roughly the equivalent of 5 x 30w incandescent bulbs. which is 150w in total, or 1500 lumens, for an area approximately 3m x 5.5m (which according to this site, would require 1600 lumens). so i'm actually under the recommended amount of lumens which is a concern, because if anything, we want this room to be on the brighter side (with the ability to dim if required). we don't need floodlighting, but i'm trying to fathom what is actually safe to use!

am i also correct in thinking that 5 x smaller bulbs will not give out the same amount of focused light as a single more powerful bulb? therefore, even though the combined amount of lumens might be the same, because the light would be spread, the intensity wouldn't be as bright ...or am i way off the mark with that assumption?

thanks

 

[SUNRAY]

Which suggests you don't have much experience of how much more light you get from LED, compared to tungsten lamps. I use 2.5w LED lamps as my go to for many areas. I have just two 8w LED fittings in my kitchen/diner.

Quality of light output does vary with the type of fitting, but the one you linked to is a quite efficient design I would suggest 2.5w LED will be perfectly adequate in those.

For a start I can't tell from the pics in your link but I don't see any light spill from the top of the shade or any apparent vent holes and from that I'll guess no exit for the heat.

Second, having that hanging over a table - assuming this is domestic and not a banquetting hall - you will not be wanting massive light output. We still have a 70's rise and fall big ball, over out 9ft long dining table. Initially I used a 100W bulb but it was far too bright, we now have a 60W and dimmer.

The shade is not the best reflector, I assume your shades/reflectors are very efficient in comparison.
I believe you will not want as much as 20W of LED in those. My gut feeling is 2.5-3W of warm white or 1.5-2W of cool white otherwise you'll be squinting against the reflections.

Personally I feel bright/reflective downlights, also for that matter the current (or was it last years) steam punk fashion of naked bulbs hanging within ones eyeline with the other diners, over dining tables are uncomfortable - epecially when one gets older and wears glasses.

 

[EFLImpudence]

I'm glad you did, it took me a moment to read it a second or even a third time.

The sticker actually stated 'Lamp max 20W or 5W LED'

Ah. I thought that was your typo.

So the manufacturer says you can use a max. LED of 20W or 5W.

 

[ericmark]

With respect I find many LEDs run hotter than the same power incandescent, classic example being 15W SES candle bulb which runs warm - certainly comfortable to touch whereas a 6W LED version runs too hot to touch in the same fitting.

That does not seem right, however just removed a faulty LED bulb and it was very hot, but also clearly faulty.

If a bulb consumes 6 watt, that energy must go some where, it may leave the bulb as light, heat, even radio waves, but it must leave the bulb.

Leaving the bulb as heat circulating air removes the energy, leaving as light, then any surface it hits will turn some of it from light to heat, and the darker the surface the more light is changed into heat.

So the same fitting with LED, CFL, and Tungsten will get hot in different areas, the pearl dome of the LED candle bulb is likely empty, the chips are before the dome, so the base gets warmer and the plastic which replaces the glass runs rather cool.

Look at a range of LED bulbs and the lumen per watt can vary from 60 - 110, so one LED bulb can end up twice as hot as another with same rating.

But if the shade says 25 watt then that is the limit be it LED, CFL, or Tungsten, it is watts that matter not the lumen.

 

[JohnW2]

.... I find many LEDs run hotter than the same power incandescent, classic example being 15W SES candle bulb which runs warm - certainly comfortable to touch whereas a 6W LED version runs too hot to touch in the same fitting.

Interesting. I'm not sure to what extent the base (SES vs BC) makes a difference, but my experience with BC candle bulbs is quite the opposite of that. A 7W LED one gets only slightly warm whereas a 15W incandescent (rapidly) gets almost too hot to touch.

However, of perhaps more relevance to the discussion, light fittings, lamp holders and shades etc. usually come/came with a 'maximum wattage' marking of 25W, 40W or 60W - and even 25W (let alone 40W or 60W) is way beyond the size of LED lamp/bulb that anyone is likely to want to put into it

Kind Regards, John