OK, I confess… I’ve got several low voltage halogen lights in the kitchen ceiling!
In my defence, I do have some of those “puck” 7W compact fluorescent lights under the cupboards – see http://www.heralighting.com/hera/fluoro.html – and a low energy pendant light over the table. I did do a trial of a 7W cold cathode (fluorescent) GU10/240V lamp but the light output was pretty poor, even after warming up. I reckon the problem is that, as the light is diffuse, having it in a recessed fitting just means a lot is lost or doesn’t reach the worktops. I see Screwfix do a bigger 11W version (it’s taken them a while to stock many low energy lamps) now but I’m still skeptical as to how effective it would be compared to a 20W halogen. Of course the most efficient means of kitchen lighting (apart from natural light!) would be a couple of double 6ft fittings with bare fluorescent tubes (e.g. 4 tubes at 36W)… rather like the ones we removed from the old kitchen! Not exactly the most elegant design though.
Incidentally, I struggled to find much information on the pros and cons of 240V vs 12V halogens. The general consensus seemed to be that low voltage was slightly more efficient, especially when coupled with electronic transformers (I used Osram), however I couldn’t find any proper like-for-like comparisons.Anyway, after spotting a press release for them about 6 months ago, I see you can now buy Philips Masterline (ES) halogen bulbs. These are new 12V lamps which Philips claim are up to 40% more energy efficient than standard ones (something to do with reusing the heat emitted by the filament). More info here:
http://www.prismaecat.lighting.philips.com/LightSite/Whirlwind.aspx?eca=LEPPLG&cpf=GBEPEN&stg=ACT&lan=EN&cnt_key=HMASLES%20+|PHL|871150041367371+++&ecu=LMP|PHL|EP&t=3&tree=0&scr_md=1111&leftnav=2_1&nav=Null&loc=Null
(note: this is a long link which will probably stop working soon – if so just search their website for “Masterline ES”)
There are many variants of the lamp (power, angle of beam and fitting) and I was curious as to how much more efficient they are. Therefore I looked up the data sheets for each model and plotted a chart of light vs power for Masterline ES compared to Brilliantline Dichroic lamps which I assume is a standard range (click image to view):
Whilst this graph is a bit busy you can see that, for a given beam width, the ES lamps are either lower power for the same light, or more light for the same power (or both). E.g. 36 degree spot: a 20W ES bulb gives 1000cd which is the same as a 35W BD lamp, i.e. 43% less power. At higher powers the saving may not be quite as much, e.g. 35W ES = 1050cd which is only slightly less than the light from a 50W BS, i.e. 30% saving.
Note that, surprisingly, the 20W BD lamp is much more efficient than the 35W version (assuming I’ve not made a mistake!) – it gives 780cd compared to 1000cd i.e. the 20W ES bulb gives 22% more light for the same power. Or looking at it another way if you upgrade your BD lights from 20W to 35W you only get 22% more light for 75% more power consumption! Needs a little more investigation I think…
Anyway, this is all very encouraging. I think congratulations are due to Philips for this new product; hopefully over the next couple of years they, and the other leading manufacturers, will continue to improve the efficiency of halogen lamps and their new designs will become the norm.
Restoring & "Greening" an Old House 
June 18, 2007 at 4:50 pm
Am renovating are whole house and sweating the trade-off between efficiency (flourescent) and attractive (halogen) light on a room by room basis. Hard for me to sign off on flourescents in the kitchen/living room/bedroom, but easier in hallways, laundry room, etc.
Where’d you come out on all this? Thoughts in general on the subject?
— Bob
June 19, 2007 at 9:02 pm
Hi Bob
Yes, it’s tricky. I don’t think there’s much debate in the kitchen, though I’ve found a glass pendant light over the table with a spiral compact fluorescent works far better than I had expected. I think it’s only a matter of time before there are new “designer” fluorescents for the ceiling though.
I do recommend trying out different power and beam width halogens. Our electrician put in 50W (I think they all do) but the bulbs I’ve replaced so far have been with 20W or 35W and “management” hasn’t noticed any difference. I’ll definitely be buying some of the Philips bulbs too.
I’m not keen on halogens in bedrooms anyway – I personally prefer softer, reflected light. The worst design I’ve come across was in a hotel once which had halogen bedside lights – I put one on in the night (when I suppose your pupils are fully dilated) and nearly blinded myself!
I’ve got 11W or 20W fluorescent bulbs in all hallways, in sealed lights in bathrooms etc – an easy choice and modern CF lamps warm up very quickly. In the lounge I’ve got 7W candle bulbs in 2 double fittings – whilst better than filament lamps (which were 40W, i.e. 160W total cf 28W now) such small double fittings are not ideal. In another room I’ve got a couple up uplighters with 11W CF lamps in them which work fine.
As you say though it’s a trade-off though. I think halogen downlights are at the peak of their popularity now and we’ll see more innovative, but just as attractive, fittings coming out soon.
Simon
June 25, 2007 at 9:17 am
Hi there – just read with interest your blog on low-energy GU10 replacements. I’ve just replaced 8 240v/50w halogens in our kitchen (which were always blowing) with equivalent low-energy bulbs. The warm-up time is a bit of a problem and the overall light output is not as good, so we’re now probably going to need some supplementary lighting to help out. The other problem was the GU10 replacement bulbs had slightly thicker necks than the old halogens, so we had to replace the fittings as well. I’ve also replaced a dozen other 40w ‘ping-pong’ bulbs with low energy replacements (Megaman 7w from http://www.ebulbshop.com) which are great – though again, warm-up time means you dont get instant light!
Ideally, the kitchen could do with a couple of 6ft fluorescent tubes, but aesthetics is a problem – why can’t someone design an attractive fitting for these?…
Cheers, Martin
June 27, 2007 at 4:37 pm
Interesting suggestion Martin. As I mentioned I was disappointed with a 7W GU10 CF bulb and so ruled them out. However I see on the website you suggest that they have 11W versions so maybe they are more suitable.
I also found my GU10 CF was very slow to warm up. However I’ve found the warm-up time of (larger) CF bulbs to be improving year on year – there’s probably an inverse correlation between this time period and their ugliness though!
Simon
July 23, 2007 at 12:29 am
I’ve had a similar dilemma in greening my basement flat. When I bought it, the ceilings had old-style R80 screw-in reflectors everywhere. These gave off a very nice light with incandescent bulbs, and I’ve found the Megaman replacements a very good substitute, startup times notwithstanding.
However, now I’ve had the ceilings replaced with an acoustically isolated system (noisy neighbours), so any light fitting has to be flush. The ceilings are very low anyway, and for now I’m sticking with “strips of GU10s on a bar” type fittings. The Megaman GU10s are OK…ish The 9W version gives off a reasonable amount of warm light, but be aware that the 11W variant, while brighter, is noticeably colder.
The compromise I’ve come to is: CFL GU10s in hallways (tend to be left on for long periods in a dark basement); CFL GU10s in rooms I don’t spend too much time in; halogen GU10s in living areas in winter (inefficient, but at least the “waste” heat is keeping me warm!), replaced with CFLs in summer.
Simon (still waiting for bright, cheap, efficient LEDs to be perfected!)
July 26, 2007 at 9:37 pm
At the risk of sounding like someone asking for “the gift of chastity, but not yet”, I do wonder whether it might not be worth waiting for Simon’s cheap LEDs to arrive. I’ve replaced quite a few bulbs with compact fluorescents, but I can’t help thinking about the 4 mg of mercury in each one, which is going to lead to a big disposal problem. Currently I think it would cost around £40 to replace a light bulb with the same brightness of LEDs, but these are products of the semiconductor industry and as such are subject to the rapid price falls characteristic of that industry when investment gets going. Certainly companies like Phillips are now spending a lot of money on R&D as well as buying up many small companies with useful IP in the area. I think it’s quite reasonable to imagine LEDs halving in price every couple of years, with improved colour balance and efficiencies around 50% (compared to about 5% for incandescents and 15% for compact fluorescents), so given 5 years or so it will be quite clear what to do.
July 27, 2007 at 9:58 am
Thanks for an interesting comment Richard (and Simon K) – it poses several questions:
It had occurred to me that there’s quite a lot of electronics in a CF lamp. Is the 4mg of mercury in the “tube” or the electronic components? How does this compare to other “disposable” electronic devices? I see that waste tips are now recycling fluorescents (presumably they are covered by WEEE). You can get fittings which have the control gear in them and just replace the tube, e.g. “2D” products (or the traditional 6′ tube of course!): would that be a better alternative?
I hadn’t realised that CFLs were only 15% efficient – where does the rest of the energy go? Perhaps into invisible radiation as they don’t get very hot? Or is it that the amount of light we need actually equates to a small amount of energy (it should be possible to make some estimates but I’m being lazy!).
Finally how much LED technological progress do we need for mass market adoption in 5 years? E.g. how much light do you get from say a 2W GU10 LED lamp today compared to what we’ll need?
Anyway – at some point I’ll mull it over and post a entry for LED lighting.
Simon
July 31, 2007 at 12:45 am
I’ve just found this site – thanks Richard. I recently replaced our kitchen and lighting proved to be the biggest headache. My wife favoured fluorescents – she’s from Asia, where they’re the norm – and I was concerned about efficiency and colour rendering. We also wanted bright, even illumination rather than pools of light and dark.
The electrician I chose specializes in LEDs and initially suggested we light the room with them. But when we seriously discussed current products they didn’t make sense as regards overall room brightness and colour rendering. I spoke to a few suppliers and I’d say it was worth revisiting the question in two or three years. They’re OK for accent lighting presently but not for general room illumination, IMO. The economics isn’t too bad in theory but since you pay essentially all the cost up front you really need to trust the manufacturer’s life estimates.
That left fluorescents and a little investigation led me to T5 triphosphor tubes. They have good efficiency, good colour rendering, wide choice of colour temperature and long life (up to 20,000 hours). They use external electronic ballasts so at least that waste is avoided if a tube ever needs changing.
The fittings are the weak point. I couldn’t find anything nice in retail shops and though I saw some commercial luminaires in catalogues that might have worked, I wasn’t able to find a manufacturer or distributor who would tell me where I could see one. Eventually I just bought under-cupboard fittings and put those on the ceiling.
We have 4 x 21 W fittings (i.e. 4 x 2000 lumen) with daylight bulbs. They’re fitted over the worktops in a 12′ square room so there are no shadows and give a good light for cooking and cleaning up. We also have 4 x 8 W under the cupboards that give a softer light at other times and save power.
I know I should worry about the mercury but if I have the right numbers, I’ll need to carelessly discard a few hundred tubes before it matches the contribution the fillings in my teeth will make to global pollution! The mercury is in the tube BTW, Simon.
Dave
August 6, 2007 at 1:42 pm
I remembered one thing to be wary of if you’re buying LEDs. Apparently there’s an inverse relationship between output and lifetime. So you can run LEDs brighter than their rated output, but this comes at the expense of operational hours. Add unscrupulous vendors to the mix, stir well and caveat emptor!
August 6, 2007 at 9:04 pm
Yes, I’m sure heat contributes to LED failure and if you pump more current through to get more light they will run hotter than designed.
Incidentally I suspect excessive heat also leads to premature failure of halogen lamps – I reckon it’s worth paying more to get aluminium-backed ones that throw the heat forward.
That’s a good idea to use under cupboard fluorescents on the ceiling – some of the slim ones are quite neat. Another option, when there’s space, might be to put them on the top-front edge of the wall cupboards and bounce the light off the ceiling.
S
August 13, 2007 at 12:55 pm
I thought about bouncing the light off the ceiling but wasn’t sure how much extra wattage I’d need to compensate. My wife and I find the tubes’ appearance acceptable so I didn’t invest any more effort!
There are some fancy directional fittings for shop display applications that might be another possibility.
January 20, 2008 at 11:06 am
I bought an electisave monitor and found that if I use my fluorescent lights under the cupboard, MORE energy is used that the 4 halogen lights that I have on an separate switch. I am looking for a replacement of my fluorescent fittings and saw a very good eco version for undercupboard lighting in an Ecohouse in Witney oxon. I have not been able to find out what lights they were but the following look similar http://www.johncullenlighting.co.uk/index.php?moduleID=4&categoryID=8&productID=168
I hope this helps
K