Incandescent bulbs - decision, plus Edison Screw question

In article ,
Steve Thackery wrote:
Bill Wright wrote:

People seem to be saying that LEDs are comparable, in terms of light
output versus power consumption, to CFLs and halogens.

No they didn't!! Nobody mentioned halogens. Halogens are hardly any
better than normal incandescents.

actually some 20-30% better.

Both CFLs and LEDs are about five times more efficient than
incandescents. Most of the debate has been about whether LEDS are
significantly more efficient than CFLs. As far as I can tell, they seem
to be *slightly* more efficient, but published figures seem to vary
somewhat. LED technology is developing rapidly, which is probably why
it's so hard to find any agreed-upon efficiency figures for LEDs.

How about doing a preactical experiment/ You should find LEDs noticably
more efficient.

But even so, they seem to be broadly in the same ballpark as CFLs, and
probably tending towards the more efficient side. Halogens are nowhere.

--
From KT24

Using a RISC OS computer running v5.18

Roderick Stewart wrote:
On Wed, 28 May 2014 09:31:46 +0100, "Norman Wells"
wrote:

Go on then, sell me the advantages.

I thought we already had, but to summarise, they're more efficient,

Only slightly if you take heat emitted into account and what that
heat does.

Similar light output for about a fifth of the electrical power is not
what I would call "only slightly" more efficient. I'd call it quite
dramatically more efficient. How would you describe it if a new car
went five times as far on a gallon of fuel?

I accept your argument that the waste heat from a less efficient bulb
can sometimes be useful, but this depends on circumstances and is not
controllable.

That's true of course, but it's way below the minimum heat energy you'd
want in a room if you have the heating on, which I say is most of the
time you want the lights on. The control comes from the thermostat on
the heating system, which will come on somewhat less often because of
the heating effect of the lights.

Far better to have less waste heat from devices not
intended to produce it so you can decide when and where heat is
actually wanted.

Ideally, yes. But the above factors apply.

The thermal efficiency of an entire room including
electrical equipment is a valid concept, but we are talking about
light bulbs.

they run cooler,

No real advantage in itself.

Until you need to change one that's been running for years, or unscrew
the plastic collar to remove the lampshade, and the plastic crumbles
in your hands and the plastic insulation of the cable cracks. Or until
you burn your fingers on a desk lamp or bedside table lamp.

I don't actually see those as sufficiently disadvantageous, though, to
warrant any extra expense.

they give a pleasant light and don't go dim and flickery like CFLs,

So do incandescents, which are also a lot cheaper and more versatile.

Cheaper to buy but more expensive to run, and hotter, and more
fragile. Oh dear, I seem to be repeating myself...

The point about 'more expensive to run' is partially true. If you take
it that the heat they produce is useful heat, then the difference in
cost, though, is only the difference between the price of electricity
and gas for the amount of power consumed. It's certainly nothing like
the difference between the stated wattages on the respective lamps which
greenies on a mission to save the planet would have you believe. 100W
incandescent = 15W CFL or LED? You save 85W!

No you don't.

Bill Wright wrote:
Norman Wells wrote:

There's no point in trying just for the sake of trying. If there's
no obvious advantage to be gained, and there apparently isn't, why
bother?

What terrible nonsense! You're saying that there's no point in pure
science research.

It depends. If you have an effective condom already, there's no point
in trying to make one out of meccano.

Bill Wright wrote:
Norman Wells wrote:
Steve Thackery wrote:

Just by way of example: as far as I'm concerned, any lamp that
flickers before it comes on might - arguably - work, but it doesn't
work well enough for me so it gets replaced. Ditto if it's too dim,
takes too long to brighten, or gives off light of the wrong colour.

You're referring of course to CFLs. Weren't we told how wonderful
/they/ were when they were introduced?

You were told that by greeny ********-mongers. Not by anyone here.

Maybe not, but the arguments for LEDs here are strangely reminiscent.

Roderick Stewart wrote:
On Wed, 28 May 2014 09:41:48 +0100, "Norman Wells"
wrote:

Have we still not convinced you to give LED bulbs a try? :-) The
initial purchase cost is higher than for filaments, but I
sometimes justify a purchase to myself by deciding its cost has
come from the "curiosity fund", and is thus valid because it
could be interesting.

Go on, you know you want to.

But why should I? What's in it for me, or anyone else for that
matter? What good will it do?

It may enlighten you, in more ways than one.

Are they 'progress' or just 'different'?

There's an easy way to find out, and it's not very expensive.

You can't know the value of a piece of knowledge until after you know
it, so if the value of the knowledge is what determines the value of
the effort needed to get to know it, you'll never know it at all.
Perhaps you need to apply a value to curiosity.

I'm curious about a lot of things. But I'm not particularly curious
about reinventing the wheel. Am I odd?

Steve Thackery wrote:
Norman Wells wrote:

You're referring of course to CFLs. Weren't we told how wonderful
they were when they were introduced?

We were. So what did I do? I bought some and tried them and reached
my own conclusion, which was that they were dire. Every so often I
would buy more, in the hope that they had improved, and I was right -
they did improve. Never really to my satisfaction, as I said.

I also tried a few LED lamps, and hated those too, for being too blue
and too dim. But every so often I would try another and quite
recently they improved a lot, surprisingly quickly. Now I like them
very much.

You see? I paid little heed to what we were told, did my own
research, and reached a very satisfactory conclusion.

Now try incandescents. They're even better!

charles wrote:

How about doing a preactical experiment/ You should find LEDs
noticably more efficient.

Primarily because it is not trivial to measure the lumens output of a
lamp, because you need to measure the total "amount" of light given off
(which in reality means you have to measure the intensity at every
point of an imaginary sphere with the bulb at its centre).

The lumen isn't a measure of brightness per se, because you can make a
light brighter by narrowing its beam spread. Rather it's a measure of
the total number of "light watts", which is then adjusted to allow for
the characteristics of the human eye (i.e. converted into "useful,
visible light watts).

--
SteveT

Norman Wells wrote:

Am I odd?

You don't really need that answering, do you? :-)

--
SteveT

Norman Wells wrote:

It depends. If you have an effective condom already, there's no
point in trying to make one out of meccano.

But there IS a point in trying to make one that might be:

1/ less prone to rupturing
2/ less prone to coming off
3/ reduces sensitivity less

You see? If not, the implication is that condoms have reached
perfection.

--
SteveT

On Wed, 28 May 2014 14:07:06 +0100, "Norman Wells"
wrote:

I'm curious about a lot of things. But I'm not particularly curious
about reinventing the wheel. Am I odd?

You may have noticed that the wheels on most cars on the roads are not
made from solid wood, so somebody must have reinvented them a few
times. Do you think we should have stopped all attempts to improve
lighting after the tallow candle, on the grounds that we'd got it as
good as it needed to be so there was no point trying anything else?

Rod.