How does lighting work?

enya_3

I have an olde style ceiling light in my bedroom with five little old-style (incandescent) 25W bulbs, each with a tiny shade (aw!). It used to have 5 x 40W bulbs but 200W struck me as waste of money - although now it's not bright enough.
I want to replace it anyway and I'm looking at a new light which has 3 G9 40W bulbs. How bright is that likely to be? It sounds to me that 3 x 40W is less than 5 x 25W so it will be dimmer, but I suppose it isn't as simple as that.
All I can see on websites is that it is the lumens that are important, but I don't know what they are!! How does it all work?

ormus

http://en.wikipedia.org/wiki/Lumen_%28unit%29

an explanation of lumens. its fairly complicated. but basically the more lumens, the brighter the bulb.
since last month all EU lamps must state the lumens, not so much the wattage.

Owain_Moneysaver

enya wrote: »

I have an olde style ceiling light in my bedroom with five little old-style (incandescent) 25W bulbs, each with a tiny shade (aw!). It used to have 5 x 40W bulbs but 200W struck me as waste of money - although now it's not bright enough.

Could you change the bulbs for low-energy ones - they usually stick out a bit more, but are a lot cheaper to run.

These are only 35 mm diameter, narrower than most others.

If the ordinary 'stick' bulbs are acceptable then you may find a suitable type in the supermarket, Tesco had loads for 10p the other week.

gmgmgm

Lumens are more accurate, but for what you're doing, wattage is fine. You're comparing 5x25 and 3x40. A difference of 5W. So nothing really.

In order to make it brighter, you'll need more efficient lights e.g. energy saving ones. The new ceiling light doesn't sound worth it (and for the price, you can probably run the old brighter bulbs for a very long time).

enya_3

gmgmgm wrote: »

Lumens are more accurate, but for what you're doing, wattage is fine. You're comparing 5x25 and 3x40. A difference of 5W. So nothing really.

In order to make it brighter, you'll need more efficient lights e.g. energy saving ones. The new ceiling light doesn't sound worth it (and for the price, you can probably run the old brighter bulbs for a very long time).

Thanks - but I weant to change the fitting anyway. But low energy bulbs give out more light per watt (7W low energy says it's about the same as a 40W ordinary) - where do halogen bulbs fit in? Are they like ordinary incandescent bulbs then?

ormus

with modern lamps, you cant talk about wattage v brightness, (as with old lamps). hence the new rules.
running costs equate to wattage. not brightness.

gmgmgm

enya wrote: »

Thanks - but I weant to change the fitting anyway. But low energy bulbs give out more light per watt (7W low energy says it's about the same as a 40W ordinary) - where do halogen bulbs fit in? Are they like ordinary incandescent bulbs then?

Halogen lights are generally slightly more efficient (10-20%?)- but the main "advantage" of them is their directed white light. You're not going to bathe a room in warm light with halogens.
If you're intending to change the fitting anyway, then you don't need to worry too much about money saving/efficiency :-)