Confused about lightbulbs

I have two chandeliers with 5 x 40 w and 3 x 60 w golf-ball tungsten bulbs at the moment. They are both on dimmer switches. The only place I can get replacement bulbs is the corner shop that buys containers loads from China. My first option for replacement seems to be halogen, which are expensive and why they are supposed to be more ecologically friendly I don't know as the wattage will surely be the same? Second is energy-saving, but they are even more expensive and would 'show' above the glass light-shades - and not work with the dimmer switch. I have not even looked into LEDs as I know nothing about them in this context. Ideas please.

Reply to
Jim S
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Halogen lamps tend to be more efficient producing more lumens per watt than a standard lamp. But not by a very large factor.

Reply to
polygonum

I reckon about 25% more efficient - based on practical experience; But it could depend on the type of lamp.

Reply to
charles

Halogens can be run hotter which pushes the peak of the radiation profile more towards the visible (for ordinary tungstens, the peak is in the infra-red). So more of the energy input comes out as visible light.

Reply to
Tim Streater

They are more efficient, so you can use lower wattage bulbs for the same light output. Indeed many are lower wattage than the 'normal' equivalents.

Reply to
Dave Plowman (News)

200W plus 180 W = 380 W when flat out, roughly 22p/6hr evening (10p/unit(*)) roughly. £80 odd quid/year.

No halogens have a lower (75% ish) wattage for a similar light output. Halogens are dimmable but ideally you don't want to run them significantly dimmed for long periods as the tungsten cycle within the capsule doesn't work properly and the tungsten from the filament gets deposited on the inside of the capsule reducing light output and shortening their life. The colour temperature is also higher than ordinary incandescant so the light may appear harsh.

You can get dimmable energy saving Compact Flourescent Lamp (CFL). The extra cost is offset by the lower power consumption and longer life.

Your total power consumption with CFLs would be around 100 W. Based on 9 W CFL for the 40's and 15 W for the 60's. A CFL upright in an open fitting will probably last 8000 hrs or longer, a good 4 times longer than most ordinary tungsten bulbs using 1/4 the energy. CFL tend to be "soft start" ie they take a minute or two to get to full brightness, for somewhere were they are on for long periods this isn't an issue IMHO. The colour temperature can be a bit "odd" but modern ones are much better than ones from 10 years ago.

The big problem with most LED lamps so far is that they are directional, spot lights, downlighters etc. There are a few "corn cob" types about that might be OK in a chandelier or see the "New style LED Light Bulb" thread.

Dimming is again a problem having said that do you really *use* the dimmer to adjust light levels or is it just a "set and forget"? If the former you could probably select your required light level by selecting suitable output bulbs and run them without the dimmer. Mentioned here as LED struggles to get decent light levels but if you don't need the flat out light level of what you have. LED power consumption is a bit lower than CFL but they cost more.

Bottom line, the ordinary tungsten is expensive to run and I expect you are changing a bulb around every 4 to 6 weeks. Halogen will make some savings, I've not done the calculations of power saved v cost v life for halogen. Halogens cost a bit more but I think have a similar life compared to ordinary.

CFL will almost ceratinly end up in "profit".

LED probably will as well but will be very dependant on the capital cost of the lamps. Life should be longer than CFL, like CFL the electronics suffer from overheating in some enclosed fittings.

The only real way to be moderately sure is to build a spreadsheet to model the various lamps and their total overall costs. In your situation I'd take a good look at LED and be prepared to pay quite a bit for a quality, known brand, bulb on the basis of greatest energy saving and life. The fall back would be CFL.

Reply to
Dave Liquorice

In article , Tim Streater writes

Just to add, they do actually use less energy because the sell 18W halogen for 25W replacement and so on.

Any energy saving turn to shit however when the lamps are dimmed and not used at highest efficiency super hot mode.

Reply to
fred

Are you saying they use more electricity when dimmed?

Reply to
Dave Plowman (News)

More electricity *per lumen*, yes.

So do normal bulbs.

Reply to
John Williamson

In article , Dave Plowman (News) writes

I'm saying that you lose the efficiency benefit of halogen when they are not running white hot, they just become normal lamps.

Actually, because of their high temperature optimisation, they may become less efficient than normal GLS when not in the zone (this is my suspicion/theory, not backed by objective evidence).

It is well known that 50% dimmed GLS lamps still use 75% of rated power with efficiency getting progressively worse the more the lamp is dimmed.

End result is that it's not energy friendly to have a 380W populated fitting mostly running dimmed to 1/4 brightness as it would probably still consume about 190W.

Relative efficiency experiments of dimmed halogen vs dimmed GLS left as an exercise for those with the time.

Reply to
fred

They are also considerable less robust as well!

Brian

Reply to
Brian Gaff

Mains ones, yes. 12V, I think are more robust.

Reply to
polygonum

Proportional to the amount of light produced, yes.

Reply to
Tim Streater

Tungsten candle bulbs? Clear ones should still be easy to get.

Tim

Reply to
Tim+

That's the only ones I can get (from the Chinese container shop) and he's run out.

Reply to
Jim S

You can keep your tungsten filament bulbs, thanks. I'm glad I didn't stock up on the things before they started to be replaced by the low energy ones. Tungsten nowadays doesn't last 5 minutes before they go phut. There was a time, decades ago now, when they would last and last and last but thanks to China that's history. I don't begrudge the extra cost of 'green' bulbs 'co s they last a hell of a lot longer and are cheaper overall when all things are considered.

Reply to
orion.osiris

Not more electricity but you would be better off missing one lamp out entirely than dimming several of them at once. Lumens per watt goes down radically as the filament temperature decreases.

Not only that but when dimmed you compromise the internal halogen based recycling chemistry that prevents the envelope from going dark with evaporated tungsten from the filament.

The lamp will dim OK on a dimmer but it doesn't do it much good. I think some of the harm can be undone by running them hot again at full power.

The latest generation of led lamps are getting to be very good but are still fairly expensive at present. Try one out of Amazon and see if it will do what you want. I have been caught out by one that was nominally

60W equivalent being too bright for the intended position!
Reply to
Martin Brown

Maybe I'm missing something but the seem to be plenty on Amazon (and I'm sure other retailers).

Tim

Reply to
Tim+

Whether they are cheaper in the long run is immaterial to many people. If the don't provide the right colour balance, light distribution, response time or general functionality of a tungsten bulb then they're not the right answer for many folk.

It seems illogical to me that you can freely go out and buy and run any size of fuel guzzling vehicle if you can afford to run it but we're not being allowed to make a free choice over light bulbs.

Tim

Reply to
Tim+

Jim S explained on 07/07/2013 :

Halogen lamps burn whiter/brighter for the same wattage, so are more efficient. You can buy dimmable 'energy saver' lamps, but they are not nearly so effective as ordinary lamps when dimmed. You can also buy a version which have a built in dimmer system, which is operated by on off switching. They are quite efective, but rather fiddly to use, especially if there is more than one lamp on the switch.

Reply to
Harry Bloomfield

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