Another lightbulb thread

[MdB]

I'm sure that there has been a general increase in the performance of the phosphors as the technology has improved but they still produce many times (orders of magnitude) less light per unit area than an incandescent bulb. It is for this reason that I doubt that there will ever be a good compact CFL spot light (the emitting area needs to be a lot smaller than the size of the reflector).

 

[Flyfisher]

Interesting. But the higher light output must surely require more input power (can't get 'owt for nowt - as Newton would have said had he been a Yorkshireman), so what's going on inside the bulb? More ions to energise the phosphor?

 

[MdB]

Interesting. But the higher light output must surely require more input power (can't get 'owt for nowt - as Newton would have said had he been a Yorkshireman), so what's going on inside the bulb? More ions to energise the phosphor?

For the same technology, yes, more light output means more energy input and in the case of CFL, more ions bouncing around. So a 50W CFL will have 10 times the surface area and 10 times the light output of a 5W CFL (assuming that they have the same efficiency which is approximately correct).

 

[TimM]

Our house is lit nearly entirly by the CFL's we were sent through the post 5 years ago free by the electricity company. I've never understood what all the fuss is about - they light up nearly instantly and I don't think anyone but a lighting designer would notice the difference. Maybe I've just got used to it (now where's my torch?). Just about to start replacing the task lighting with LEDs though, got to think about my electricity bill...

 

[Nigel Watts]

How does the performance of a candle compare? I guess if its made from beeswax it has zero net carbon impact even though it must be very inefficient.

Modern bulds are still quite troublesome, both in terms of qulaity and quantity of light and I have had to revert to old fashioned ones in some lamps. I read somewhere that they get dimmer with age. It seems to be happening with me (and my lightbulbs too).

 

[AMc]

I know this isn't the best answer in the world, but there is no substitute for research.

I had 4 x 100W uplighters in my front room (thanks to a former occupant) on a wall mounted dimmer. Even with 60W equivalents it was too bright so I needed the dimmer. I spent a lot of time looking for CFL replacements that were switch dimmable. I finally found this article from 'Lighting' which I assume to be a trade magazine comparing several.
http://www.goodenergyshop.co.uk/Library/Categories/Light%20bulbs/LightingArticle%5B1%5D.pdf
linked from this place which sells them
http://www.goodenergyshop.co.uk/details.asp?ParentID=&CSS=All&id=39

I was fortunate enough to come across them in Homebase reduced. I bought one and took it home, very pleased with it compared alongside the incandescents in place so went back and bought 3 more.

I did a cost/benefit analysis and based on a a 15 month usage of 3 to 4 hours a night at 14p a unit the bulb would begin to pay for itself in savings. One failed after a few months but the manufacturer replaced it (kept the box and receipt). I believe I'm now past the point where the savings outweigh the capital cost

I won't buy a bulb without getting a quoted colour temperature - having bought some morgue like LED GU10 downlighters. Ironically the worst CFL came from Morrissons and cost £2 and the best non dimmables I have are from IKEA in packs of 3 for £3.

 

[nataliecampbell]

We use this place, there is a store only ten minutes from us in Maidstone (there are others around the UK) but they also do delivery for £4.99.

The bulbs themselves are only about 40p each.

http://www.tlc-direct.co.uk/Main_Index/Lighting_Menu_Index/Lamps_and_Tubes_Index/Candle_Lamps_SBC/index.html

Hope this helps.

 

[Moo]

We've just reached the end of our stock of crown-silvered light bulbs.
Is there an equivalent in the range of eco-friendly ones?

 

[MdB]

We've just reached the end of our stock of crown-silvered light bulbs.
Is there an equivalent in the range of eco-friendly ones?

For use with parabolic reflectors to give a good directional output then no. They will never exist with CFL and are unlikely to produced with LEDs as LEDs are directional by themselves.

For use with diffuser to reduce the glare then any CFL is suitable as they have a diffuse output.

What type of fitting are they to go in?

 

[Flyfisher]

Interesting discussion about CFLs on BBC R4 'More Or Less' this afternoon.
http://news.bbc.co.uk/1/hi/magazine/8406923.stm
http://news.bbc.co.uk/1/hi/programmes/more_or_less/8404720.stm

 

[FamilyWiggs]

Interesting discussion about CFLs on BBC R4 'More Or Less' this afternoon.
http://news.bbc.co.uk/1/hi/magazine/8406923.stm
http://news.bbc.co.uk/1/hi/programmes/more_or_less/8404720.stm

Yes I caught some of that in the car FF. Interesting as it went through the maths of the "80% reduction in energy use" plastered across the CFL box. Seems when you factor in the additional heat your boiler will need to replace that GLS bulbs provide and CFL don't, then the eneregy saving is closer to 20-30%. As a result CFL manufacturers are thinking of reducing the claim from 80% to 70%!!

 

[Moo]

What type of fitting are they to go in?

Oh dear - that does sound like gloomy news. They're just ordinary bayonet fitting table lamps. I like the crown-silvered bulbs because they don't 'leak' light upwards, but just send a pool of light on to the table they're standing on.

 

[Flyfisher]

The programme also discussed therelative brightness of CFL and incandescent lamps and an EU person (I think it was) recommended dividing incandescent wattage by 4 for CFL equivalent. Thus, a 'normal' 60W bulb should be replaced by a 15W CFL for eqivalent light output, not the 11W that manufacturers usually claim as equivalent. Then a bit later someone said that figure should really 3 to account for the drop in light output as CFLs age, thus making a 20W CFL equivalent to a 60W incandescent.

It was also admitted that the life of CFLs is shortened if they become too hot in operation, as is typical - apparently - in many ceiling light fittings. This probably explains why we've had to replace quite a few CFLs in some kitchen ceiling-mounted lights over the past few years.

 

[MdB]

http://news.bbc.co.uk/1/hi/magazine/8406923.stm

 

[Me!]

I spent many years trying to find a cfl that was a) a nice warm colour light, b) didn't flicker when started, c) bright when first switched on, and d) cheap!

I finally settled on these Philips ones

The first couple of times a new one is used, it is dim to start with. But, after a few hours use and a few on - off cycles they get much better at starting quickly. They are never going to be full brightness when first turned on, but these really do only take a few seconds to brighten up. Also, they are without doubt the best colour of light that I have found from any cfl at any price.

So, for any of you unbelievers out there, please just try one, but not from that Amazon link I posted. I have recently bought 10 of them from Argos, where they were on special offer at just 10p each. No, that is not a typo, just 10p, £0.10, one tenth of a £, or how ever you would like to express it. I have also prevously bought them in B&Q and Morrisons for about 20p each. They often seem to come on special offer as they get subsidised by various energy companies, so just keep an eye out for a good price and if anyone finds them for less than 10p, then please tell me where!

 

[FamilyWiggs]

I'm quite getting into this now. I replaced the batteries in our OWL electickery monitor the other day and was astounded.

Have now ordered a few different candle bulbs to experiment.

These webisites carry a reasonable range:

http://ebulbshop.com/acatalog/Energy_saving_Light_Bulbs.html

http://www.lightonenergy.co.uk/Megaman-Candle-9W-p/mm-can-9w.htm

http://www.cheapenergysavinglightbulbs.co.uk/index.php?cPath=30

It's the GU10s (50w, 240v x 24 bulbs we have for kitchen/utility/downstairs cloakroom :shock: (not installed by me I hasten to add)) that seem to be killers too. Has anyone tried one of these or similar replacements:

http://ebulbshop.com/acatalog/11_watt_Low_Energy_Saver__GU10_240_Volts_Compact_Fluorescent_.html ?

I've tried a couple of the LED ones but I may as well open the curtains and cook by moonlight!

 

[DaveBrigg]

It was also admitted that the life of CFLs is shortened if they become too hot in operation

We have three in our lounge which have left black marks on the ceiling directly above, although they have lasted over two years so far.

 

[Flyfisher]

The 'shortened life' was in the context of the supposed 10 year lifetime, so it's early days yet. :wink:

Black marks on the ceiling might indicate dust on the bulbs heating up and smouldering. I've noticed that a lot on incandescents in table lamps, where the top of the bulb becomes covered with a sooty deposit, although I've never noticed it marking ceilings. Your bulbs may be quite close to the ceiling perhaps?

 

[DaveBrigg]

FF - about 10 inches from the ceiling. It must be soot from charred dust as you suggest; I was just surprised that the bulbs got hot enough to cause this.

 

[Ushy M]

Has anyone tried one of these or similar replacements:

http://ebulbshop.com/acatalog/11_watt_Low_Energy_Saver__GU10_240_Volts_Compact_Fluorescent_.html ?

I've tried a couple of the LED ones but I may as well open the curtains and cook by moonlight!

Robin, yes, we tried these, similarly horrified at the amount of elastic trickery the GU10s get through - they were hopeless. We resorted to opening the curtains and cooking by moonlight! (Actually, I took them back to the shop they were so useless)