CFL lamps and dimmer switches

[Lobster]

On our dining room wall we have a couple of candelabra-tyoe lights a bit like this:

They have hitherto used 40W incandescent BC opal candle bulbs, in conjunction with a dimmer switch to facilitate mood lighting while eating (apparently).

My stock of incandescent bulbs has now run out unfortunately, so we are reduced to eating in the pitch darkness (no, not really) because I can't fit CFLs in conjunction with the dimmer switch.

Would welcome advice on how to proceed in order to maintain the status quo. I'm having trouble sourcing either (a) dimmable CFLs which can be used with a conventional dimmer or (b) a dimmer which can be used with conventional CFLs. Which, if any, is a realistic solution? What about LEDs, might that be an option here?

Thanks David

[Tim Downie]

Stock up on 40W candle bulbs whilst you still can! ;-) Seem to be plenty on-line.

Tim

[Lobster]

Not so sure actually - they nearly all seem to be 'clear' (which AFAIK aren't banned yet?) despite most of the associated images being of opal/pearl bulbs. Also, the ones I can find are pretty expensive, so it seems to me that even if I do buy a batch, I'm only putting off the inevitable so I may as well just bite the bullet now.

David

[MuddyMike]

I recently bought a set of halogen bulbs for the dimmed multi branch ceiling fitting in our dining room from Tesco. They look like a G9 halogen inside a pearlised candle bulb. Something like this.

[Skipweasel]

Well - you can provided you leave the dimmer on full.

[Owain]

Perhaps Mrs Lobster could wear sunglasses while munching her scoff?

Owain

[Lobster]

Yebbut you snipped my bit about the requirement for 'mood lighting' - I could just change the dimmer for a standard switch if there were no other constraints... ;)

[Harry Bloomfield]

Lobster explained :

Yes you can, but the CFL needs to be a type able to be dimmed.

There are two types available. One as above for use with a normal dimmer, but they seem not very effective, sometimes appearing to strobe.

A second type, where you don't need a dimmer switch at all. The dimming electronics are built into the lamp with which you use a normal switch. You turn the switch on and off, then the lamp cycles through various brightnesses - when it reaches the level of brightness you want, you turn the switch quickly off then back on and the level is retained. Next time you use the lights, they are at the same brightness setting.

[Gareth]

I've been stocking up on incandescent light bulbs. There was plenty available in the "99p store" and also the discount section of Robert Dyas, DIY sheds and even supermarkets last time I looked, even 100W peal.

As another poster has mentioned you can now get halogen bulbs inside normal light bulbs. I have found these to be very good in that they give a much nicer light than CFLs and come on instantly as well as being a bit more efficient than the old style bulbs (but not as efficient as CFLs). I have found these in Robert Dyas but I'm sure they are fairly common.

[Michael Chare]

As another poster has mentioned you can now get halogen bulbs inside normal light bulbs. I have found these to be very good in that they give a much nicer light than CFLs and come on instantly as well as being a bit more efficient than the old style bulbs (but not as efficient as CFLs). I have found these in Robert Dyas but I'm sure they are fairly common.

I have bought clear halogen candle bulbs in Tesco. They are supposed to last longer, but the first one definitely didn't.

Michael Chare

[Peter Scott]

I've been using 20W CFLs of the sort for which you use an ordinary dimmer for about two years. They're fine and dim down very well. Sometimes they don't start up when I switch on at a low dimmer setting. Just turn them up. You also need to have more than one 20W CFL on each dimmer. Most dimmers need at least 40W to work and can damage the lamp if they don't. You can now get lower power dimmers though. Unlike incandescents you do use less energy when the lights are dimmed.

[Ian Jackson]

In message , Peter Scott writes

As an 'ordinary' dimmer works by chopping part of the supply voltage during each half cycle, surely incandescents DO use less power when dimmed?

[Harry Bloomfield]

Ian Jackson formulated the question :

They do obviously use less power, but not to the extent most people would expect. What happens is that the light output efficiency goes does drastically as the average voltage reduces and a greater proportion of the consumed power is converted into heat.

[Ian Jackson]

In message , Harry Bloomfield writes

Ah.... Of course. There will be a point when the filament will cease to glow visibly so, although it is still drawing appreciable current, the efficiency of the lamp is zero.

[Skipweasel]

You're right, they do. However, it's far from linear. Under-driven, incandescants are even more inefficient than usual.

[Frank Erskine]

With CFLs you're likely to have permanent "mood lighting" whether you want it or not.

[Owain]

But what sort of mood - bilious?

Owain

[Frank Erskine]

Precisely...

[Peter Scott]

Apparently not much. I can't give you numbers, but dimming to say one fifth of the brightness doesn't reduce the energy used to anything like a fifth.

[Peter Scott]

There's quite a lot on incandescents and dimmers at

supporting the idea that dimming them doesn't save as much as you'd expect. There are lots of numbers that I don't really want to analyse but it does say, "Often, only a small reduction in the power fed to the lamp will produce the required drop in light intensity. So ... dimming is not a particularly effective means of saving energy. However, it can drastically lengthen lamp life."

It also suggest that dimming halogens a lot might not be a good idea. "The following caveat applies to halogen lamps: the halogen cycle responsible for the extended lifetime of halogen lamps may be interrupted if the operating temperature is too low."