Adding a new ceiling light?

For an incurable tek-head, I've never gotten on with Graphical Front Ends to existing tools. The Latex raw-source format is close enough to being intelligible and rememberable (and there's the fold-out of Leslie Lamport's LaTeX book to help you) that doing it direct strikes me as simpler than dorking with a GUI.

But that's what you'd expect a dinosaur to say, right? ;-)

Stefek

Reply to
Stefek Zaba
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mistake. 2000 hour bulbs, £5 each, work out what that will cost you over the liftime of the fitting. Compare to 12v halogens, or ordinary bulbs. You might get a shock.

Regards, NT

Reply to
N. Thornton

Thanks, but I'll also need to know the estimated lifetimes of 12v halogens and ordinary bulbs to make such a comparison. Did you already do the sums then?

BTW, I was curious why my local HomeBase had two shelves full of the mains halogen fittings, in various shapes and sizes, but didn't stock a single 12V type. I'm now wondering whether that's simple popularity, as I was told, or - more cynically - to boost long term revenues from bulb replacements.

Reply to
Terry Pinnell

I did... and got a shock. A 5 bulb halogen fitting added an extra over £900 to run costs over its 30 yr estimated lifetime. Details: bulbs cost £5 each, 2000 hours life, I forget number of hours a day use, but it was in no way a high estimate.

12v halogens come in 1000, 2000 and 4000 hour versions, but most are 2000 hour. Cost 79p. Twice as energy efficient as the old fashioned GLS bulbs. Avoid 4000 hour bulbs, not as efficient.

Traditional GLS mains filament bulbs are 1000 hours and cost 17p for basic ones, or more for decorative candle types. The real cost with these is that theyre around half as efficient as 12v halogens.

The efficiency of mains halogens is somewhere between the above two.

CFL candles are by far the cheapest, but the diffuse light source and big bulbs means the style range of lighting is quite limited.

So to justify using 240v halogens your light fitting would have to be something pretty special, it would have to be worth paying £1000 for.

given the above figure, I think the conclusion obvious. The fact that new cost is slightly lower, with no transformer, will be a lesser incentive too.

Regards, NT

Reply to
N. Thornton

Provided that one doesn't mind the bilious nature of the light from CFLs.

.andy

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Reply to
Andy Hall

Well, that gives fair pause for thought, although your figures look rather extreme to me. Where can I buy those 17p 40W bulbs?

Based on a quick look in the catalogue of CPC, a supplier I use, see my own estimates here:

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stems from your 'extra' figure of £900, assuming by that you meant 'additional to purchase cost of the fitting'.

It's very simplistic, of course. For a start, there's the assumption that illumination is identical. Note that there's no 40W halogen to give an exact comparison - although 35W is close enough. And initial purchase costs of fitting (and transformers if necessary) are ignored, as is 'convenience' of fitting.

Reply to
Terry Pinnell

tesco and others.

I meant owning a 5 bulb GU10 fitting added over 900 to the cost of running it over a typ 30yr life. Now if youre not using GU10s, your excess cost will be less, but still a sizeable excess.

No, comparable illuminations were used. IIRC I think the comparisons were probably between 50w 240v halogen, 100w filament GLS, and 25w CFL.

Your table left out electricity costs, which make more difference than bulb costs. 12v is more efficient, and cfl much more so.

not really :) The point was that if you want to compare like with like on purchase cost basis, you should add something like £900 to the cost of your mains halogen fitting, and compare it to what else you could get for 900.

If you dont mind paying the extra hundreds, fine, just be aware of the true comparison.

Regards, NT

Reply to
N. Thornton

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