Correspondence with Matt Prescott of Ban The Bulb

Posted July 12, 2007 // Tagged as Articles // 2 Comments ↓

Dear Mat,

As a lighting design consultant I am somewhat dismayed at your campaign. From what I have read on your website and other articles you seem to be pursuing a campaign on a single issue, that of apparent lamp energy efficiency rather than a better measure which would be total environmental impact.

Dealing first with the energy issue it appears that you are using manufacturer’s data without qualification. The energy use data is based on laboratory tests for a lamp that is at the beginning of its service life and has run for sufficient time to achieve full light output. In reality a CFL lamp will have approximately 60% to 70% output when initially switched on, typical for many domestic uses. The life is calculated to 80% of initial lumens so an aged lamp will be giving about 50% of the light output of an incandescent lamp when switched on at end of life. It will also have lost output due to dirt deposition over many years in the domestic or commercial environment.

Secondly on this issue, the heat contribution of an incandescent lamp is not waste energy during the heating months, typically that will be 7 months of the year in North Europe. If you reduce lighting energy you increase requirement of heating energy by the same amount. I agree in predominantly cooled environments there is an issue of disposal of excess heat, however with a well designed air handling system this heat can be rejected to the environment rather than adding to cooling load.

Dealing with waste, Have you considered the impact of the disposal of CFL’s from domestic and small commercial use? There is no way of creating an economic alternative to disposal with domestic waste. Do you propose a recycling deposit for CFLs? Will you have to return a dead lamp to retailers before you get a new one? If not think of the amount of mercury, plastics, heavy metals and phosphor materials that end up in land fill or worse in incineration with the vast increase in domestic use of CFL.

Are you proposing a ban on all incandescent light sources? or are you looking solely at mains voltage incandescent lamps? How about promoting Tungsten halogen Infra red light sources as a replacement? these provide an energy saving of 25% without any loss of light quality or need to change any technical infrastructure such as lighting controls and the lamps are made of inert materials so can be easily disposed of without creating an environmental problem.

In my view the only energy efficient light-source is one that is switched off. Where light is required the least energy should be used therefore lighting control, dimming and switching, is an essential tool. It is complex and not entirely successful dimming CFLs , high intensity sources such as metal halide are not effectively dimmable using existing technology. Incandescent sources are easily controllable and instantly responsive. They also respond well in terms of extended life when dimmed compared to Fluorescent and CFL that lose effective life.

Finally to Light Quality. Light is not something we experience in a quantitate way. NO light source except incandescent provide a continuous spectrum light source. All discharge light sources distort colour and make many tasks more strenuous on the eye and brain. Cheaper domestic CFLs have poor quality gear that can create flicker at high frequencies which may not be consciously visible does affect the eye and brain. All lamp manufacturers propose CFLs that produce less light than the “equivalent ” incandescent lamp, this is at their measure of output, see above, therefore replacements invariable produce less light than was previously available. moving to the next step up in CFL will variously change the “energy saved” figure by significant percentages!

I would value your considered comments on the above.


Kevan Shaw

Design Director


Reply 1:

Dear Kevan,

I have addressed many of the points you have raised in my articles for

BBC News Online’s Green Room.

I would urge you to read these.

I am a pragmatist and primarily focused on encouraging movement in

something which has got bogged down in nit-picking.

A deadline for action would drive innovation and this is all we really need.

Most government actions would take years to implement or have trivial effects.

Here we have a technology, which though not perfect, could produce a

60% saving in carbon emissions and reduce costs.

I am open to appropriate exemptions, phasing in bans in a way that

established technologies to be subsitituted in a responsible fashion

and accept the limitations of the available technology.

CFLs can already be recycled at IKEA stores and EU legislation will

soon force all retailers to provide this service.

Daylight obviously has a better light spectrum than incandescents and

halogens can offer a similar spectrum in a way that uses much less

electricity… I use one on my desk.

For most other purposes I am afraid that the seriousness of climate

change means some temporary concessions may be needed in order to get

over the barriers to progress.

Warmest regards


My response:


I am afraid you are somewhat overoptimistic on the innovation front. The incandescent innovation has happened and this is the THIR lamp however it is not as profitable as making nasty polluting CFLs cheap in China and sending them all over the world so the lamp manufacturers are pushing the CFL. A true continuous spectrum requires heating a body up to a very high temperature there is no technology in he pipeline that is even looking at this as it is bound to be worse  in its initial stages than what we have now which has been developed over more than a century! I note that your timeline does not include developments in the 60’s 70’s and 90’s in incandescent lamp technology.

LEDs are currently stuck at a practical, real world luminous efficiency of 20 lumens per watt yet these are being pushed as an energy efficient light source although they are only the same efficiency as good incandescents. All the hype about achieving 100+ lumens per watt is laboratory  stuff and the technologies that achieve this are not directly transferrable. On quality of light issues LEDs that are white are using fluorescent technologies and not achieving good colour rendering.

The energy efficiency of real high colour rendering fluorescents is half that of normal fluorescent lamps, take a look at any proper lamp catalogue and see what I mean, what you have on your desktop I assume is a daylight fluorescent lamp, please take a look and let me know the lamp code I bet it is 850 rather than 950 that would give you a good light quality. Try finding a lamp with a similar colour appearance to Tungsten, this is preferred by the majority for domestic evening illumination, yes I have done research on this, I bet you won’t find a good 930 or even an 827 lamp that has good colour rendering or appearance side by side with any incandescent lamp.

WEEE legislation is in complete disarray as you should well be aware. Light bulbs for domestic use are a “distress purchase” they are largely bought in ones and twos from corner shops I don’t see these being able or willing to provide recycling and will doubtless be exempted as will many retailers be exempted from WEEE.

I did a study a few years ago on the effects of changing from wire wound gear for fluorescents to electronic gear. I used what little info i could get on embodied energy and came up with a payback of 15 years in saved energy for the disposal of working wire wound fluorescent light fittings and replacement with electronic gear fittings, at the time manufacturers were quoting 18 months to 2 years which was the cost of replacement of fittings.

Please will you do some numbers on the reality of the full environmental impact of replacing Incandescent and CFL and publish these if they really stack up. Your single aspect campaign is not helpful in getting the broad environmental message across.

Kevan Shaw

Design Director

Reply 2:

Hello Kevan,

I understand that we are living in a complex and cynical world.

I have not endorsed LEDs for the very reasons you have mentioned.

However, feel that the imperfect light spectrum is not enough of an

issue to prevent CFLs playing a useful role in cutting carbon


I agree that WEEE is in disarray and it can only be hoped that the

RoHS will be better planned and more sensibly implemented .

Fortunately, more people are watching now and this should mean better

preparations are made this time around.

I am afraid that some effort will have to be applied to solve the problems.

All I know is that we cannot sit still and accept that business as

usual is acceptable and we have to put the work into making the best

alternative more acceptable.

Warmest regards


So no substantiated argument and essential questions not answered!  Is this another touchy feely campaign? We need to get some solid numbers to be able to really find out the environmental impact and energy consumption of incandescent and CFL sources to make fully informed decisions.

Kevan Shaw

2 Responses

  1. […] to say on this subject – and one day we promise we will say it, but for now I leave you with Kevan Shaw’s correspondence with Matt Prescott, which simultaneously explains some (not all) of the issues and is a tribute to all the people like […]

  2. EUAN CLAYTON, Edinburgh

    October 16th, 2009 at 10:24

    Kevin, This is a typical example of an uninformed eco nazi with the ear of Government spouting his own brand of the “New Religion”, Environmentalism. Your previous paper and talk on the subject along with David McNair’s paper regarding the use of CFLs in care homes provide a far more convincing case for not using these items in many cases.
    Mr Prescott’s arguement that “some temporary concessions may be needed” falls down on so may fronts, not least of which is the Disability Discrimination Act, and catering for those with visual impairment. All in the name of ” CO2 reduction. He feels that “imperfect light spectrum ” is not sufficient arguement, perhaps he would have us go back to SOX lamps in street lighting.
    The disposal issue is one of the most serious, and should be given more consideration by the Ecomentalists. Whilst many of the among the eco lobbyists may make a special journey to a designated lamp recycling facility (assuming such a thing exists), the majority will just go in the bin and end up in landfill. It is also interesting to note that he uses IKEA, an out of town retail unit which generates huge number of car journeys ever weekend, as an example.

    He seems to have a vision of some Eco Utopia where he thinks Governments can educate the entire population into disposing of these toxic items responsibly, it simply will not happen.

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