Are energy-saving light bulbs now a thing of the past already?

Dimming probably saves minimal energy. The reduction in perceived lighting will not be a linear relationship with the reduction in power to the bulb and the dimming circuit will also take some power.

Reply to
alan_m
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Make up your own mind about the colour temperature of the bulb. You may want to buy more than one type to see what the difference in the lighting experience. Some people like warm white but myself I prefer the cool/daylight type bulbs.

You may find that if you are older a cooler/daylight type bulb seems to improves contrast and makes things like reading printed material easier.

I've not had good experiences with the LED GU10 type down lighters but for the more traditional shaped bulbs LEDS have worked well for me. I'm renovating a bathroom and have installed a LED panel light (300mm x

300mm, 20W, Daylight, £60, transformer in the loft) and it gives a perfect even illumination to the room - the only downside is that it perhaps shows up too much of the poor cleaning regime.
Reply to
alan_m

That was my first thought too but to dim down to a more 'atmospheric level' (i.e. quite dim enough to hide those difficult to reach cobwebs and hide the scruffy condition of paintwork and wall coverings) you're probably reducing the consumption by 70 or 80%.

Our perception of light levels, as you mentioned isn't a linear one. Halving the light output doesn't make it look only half as bright, just slightly dimmer. If you were to ask test subjects to say when they think the illumination level has dropped to half, you'll likely find the actual lighting level is around one quarter of the starting value.

Rinse and repeat so by the time the test subjects broadly agree on when the levels have dropped to an "Atmospheric" level I suspect the actual lighting level will be a good 3 or 4 stops down (1/8th to

1/16th). Of course, as you pointed out, the power consumption won't have dropped by as much. My feeling is that a 4 stop reduction to 1/16th of lighting level will correspond to 1/4 of the original power demand (2 stops worth).

The efficacy of tungsten lighting deteriorates as filament temperature is reduced but the reduction of lighting levels will be a surprisingly large one to reach atmospheric (assuming the full level was a decent non-atmospheric level to begin with).

So, Harry's "save a bit of electricity" is a valid point. :-(

As for the dimmer losses, they're going to be negligable (circa 1 to

2 watts max) so contribute very little to the overall losses.
Reply to
Johny B Good

LED will son be out of date:-)

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Reply to
ARW

"A new material called graphene is being used in a light bulb which could see energy bills reduced by around 10 per cent."

Seems a rather vague way of stating the benefit of 'graphine lamp technology'. If it's a claimed reduction for the whole of the electricity used in a typical home, it's damned impressive if it's based on existing CFL or LED technology lighting already in use.

Perhaps the other link will prove more helpful:

"The dimmable bulb contains a filament-shaped LED coated in graphene." Aha! That sheds a little more light. It would appear to be a 10% _further_ reduction over existing LED lamp consumption (er, I think). Perhaps this was already part of Cree's 303L/W lab sample designs demonstrated just over a year ago.

Doesn't look like graphene will give rise to the "LED will son be out of date:-)" to me so much as be a contributory technique to push LED efficacy a little more closer to the theoretical 400 odd Lumen per watt limit for a white LED lamp.

Reply to
Johny B Good

They did then. They don't now.

Reply to
harryagain

They did then. They don't now. I have some12 year old CFLs

Reply to
harryagain

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