From Mr David Haddon-Reece
Sir, — I write as a diocesan lighting adviser in response to the Revd Christine Polhill’s letter about compact fluorescent lamps (6 February). I am afraid her letter would make “grouches” of all of us who, for good and scientific reason, prefer not to light the worship spaces of our churches with compact fluorescent lamps (CFLs).
By all means, use them for ancillary areas such as porches, vestries, passages, etc., but please remember that there are two very good reasons for not replacing tungsten bulbs wholesale with CFLs without careful thought and actual experiment.
First, the measured luminous output of CFLs does not appear to match the value quoted on the packet: “20 watts, equivalent to 100 watts tungsten”. The implication here is that if all pendant tungsten lamps in a nave, for instance, are replaced with CFL, the resulting lighting levels will fall, possibly to a level that contravenes the Disability Discrimination Act. Elderly eyes may require up to six times more light than those of young people.
Second, the spectral output of CFLs may not supply the higher yellow component so necessary for the human eye as it ages, so that after a complete relamping, even with measurable lux levels satisfying the Act, task light quality may still be inadequate for a church with an elderly congregation.
To those reasons, we can add that CFLs carry at least ten times the manufacturing cost of tungsten lamps, contain small amounts of mercury, with implications for disposal, perform poorly in cold conditions, and, unless chosen carefully and very expensively, have so strong a red and/or blue component that the lit quality of a worship space is diminished (an effect I have sadly witnessed). This fails the precept that we should respect our architecture, serve our people, and honour God.
If an alternative is required as the GLS (general lighting service) tungsten “bulb” disappears from shops, then try tungsten halogen lamps. They have energy rating C, halfway between CFL (A) and GLS (E), producing more light per watt than GLS. They give a very good quality of light, are dimmable, come with bayonet or screw caps, and have double the life of a tungsten bulb — longer if you dim them slightly.
If, through lighting changes, you want to switch off power stations — nuclear or otherwise — then persuade your local authority to turn off unnecessary street lighting after midnight, or dim it to half-value; campaign against over-powerful security lights; and reduce “decorative” floodlighting on buildings. There is a middle way.
The Vicarage, Egton, Whitby
North Yorks YO21 1UT
From Mr John Bland
Sir, — So, at last we get a sensible justification for using low-energy bulbs; but what a shame the Revd Christine Polhill spoils it in her last paragraph by suggesting that their use could save a nuclear power station — the one variety with no global-warming emissions!
Common sense clearly indicates that, of the available power sources we have, nuclear is the only one to provide the world’s needs in the long term — and so much safer than coal (mining hazards) and oil or gas (exploration hazards).
Redlands, Upper Sapey
Herefordshire WR6 6XT