Are you interested in LED light?

[Don Hills]

It depends on your energy costs.
In this country, I pay about NZ 25 cents per kilowatt hour.
A 100 watt incandescent lamp costs about NZ$1. Assuming a 1000 hour life, its TCO is about NZ$26.
A good quality 23 watt CFL costs about NZ$5 (often less). Assuming a 5000 hour life (in my experience, conservative) its TCO is about NZ$6.75 per 1000 hours. Even assuming it only lasts 1000 hours, its TCO is still only NZ$10.75.
I have just over 20 lamps that see significant use. The change to CFLs has been noticeable on my yearly electricity consumption... but the main saving for me is the greatly reduced number of times I have to climb ladders to replace lamps (3.1 meter high ceilings).

Edit:
LEDs are still too expensive for GLS use here. But they already make sense for specialist applications and the price will come down.

[Basshunter]

Originally Posted by wwenze

Talking about return on investment... a superior once told me that while each LED lamp costs a lot, if you have a lot of them the payback period is shorter.

I was like

-_-

Right, like selling them at a loss, and making it up in volume.

[Basshunter]

Originally Posted by Don Hills

It depends on your energy costs.
In this country, I pay about NZ 25 cents per kilowatt hour.
A 100 watt incandescent lamp costs about NZ$1. Assuming a 1000 hour life, its TCO is about NZ$26.
A good quality 23 watt CFL costs about NZ$5 (often less). Assuming a 5000 hour life (in my experience, conservative) its TCO is about NZ$6.75 per 1000 hours. Even assuming it only lasts 1000 hours, its TCO is still only NZ$10.75.
I have just over 20 lamps that see significant use. The change to CFLs has been noticeable on my yearly electricity consumption... but the main saving for me is the greatly reduced number of times I have to climb ladders to replace lamps (3.1 meter high ceilings).

Edit:
LEDs are still too expensive for GLS use here. But they already make sense for specialist applications and the price will come down.

How do you address all the mercury you're introducing into the environment? Are you prepared to hire a HAZMAT company if you drop and break one? CFL's are not the answer, either. Also, you can't dim them. Dim an incandecent just 5% and it will last many, many years. Even the commercial lighting industry has abandoned them.

[Basshunter]

The life of flourescent lamps is stated by the manufacturer based on lab test results. It is based on the lamp being on continuously for its life. That is not a real world situation. A CFL switched on and off will have a shorter life. Furthermore, the hours stated are median average. Half burn out earlier, half last longer. The commercial T-5 and T-8 lamps with electronic ballasts are very efficient. Sadly, that technology does not transfer to what is promoted to the general public stuff made in China.
LED's are the latest technology, but for the bed side lamp, it makes no sense. Not to mention the CRI (Color Rendering Index) of LED is horrible. The incandecent lamp has a CRI of 100. All other lamp sources are compared to it, and none are equal.

[PlasticIsGood]

LEDs are good if you can do without parts of the spectrum. Experiments continue in greenhouses but I think benefits are weak. High pressure sodium is cheaper for full spectrum, but plants can cope with no green and reduced blue for much of the time.

LED lights don't project so much heat, so can be moved closer, avoiding wastful overspill.

For normal domestic use, anything other than filament lamps doesn't make sense. Halogen seems to be gaining favour in the shops. I use soft CFLs with halogen spots, but I'd rather go back to filaments and wait for the nuclear light bulb, or bacteria with firefly genes that eat household waste. Or paint everything luminous so lights aren't needed.

[tomchr]

I use an LED light in my reading light. It works very well. Unlike the halogen light it replaced, it doesn't get hot so I can adjust the light by hand. Very handy... But for more broad applications, I prefer the Compact Florescent Lights.

I think it was around September of 2007 when I installed the outdoor lights on my house. I bought the cheapest 9 W CFLs I could find at the local big box store. Mind you, unlike in Europe, low-wattage (<10 W) CFL bulbs are hard to find in the US. I paid less than $1/bulb. The four lights are on a timer that turns on at dusk and off at dawn. So figure 12 hours on-time on average. They've been going 365 days/year since I installed them. I have yet to replace a bulb. I didn't notice any difference on the energy bill. My math says the four bulbs should cost me $1.16 per month in energy on average. That's below the noise floor of my energy bill. The biggest deal for me is that I've never had to replace them. Try do that with an incandescent bulb.

In my garage door opener, I installed two "curly-Q" random CFL bulbs when the vibration rated incandescent bulbs I bought for it crapped out. The CFLs are still going strong. The first vibration resistant incandescent bulb lasted less than a year. The CFLs have lasted over six...

I see no reason to use incandescent bulbs. If you bother to buy a good CFL bulb with a color temperature in the 3000~5000 K range with a CRI in the upper 90ies, the light is indistinguishable from incandescent bulb light.

The LEDs are still too expensive for me. Especially considering that they don't save that much power over a CFL with comparable light output.

~Tom

[PlasticIsGood]

Good point about vibration. Fair enough about quality of light too, but.

Consumer knowledge can't be relied upon and should be discounted from rational debate. How much data is it reasonable to need for a simple shopping trip? In reality, for nearly every purchase requiring technical choice, people rely on standards, and standards erode individual freedom. Intelligibility is a social necessity, and filament bulbs are miles ahead.

In old houses like mine, there's also an issue of fidelity. High-tech fitments just don't seem right.

Eye-tracking LED headlights and a light thermal body suit could save me a fortune, but the house would get soggy.

[Don Hills]

Originally Posted by Basshunter

How do you address all the mercury you're introducing into the environment? Are you prepared to hire a HAZMAT company if you drop and break one? CFL's are not the answer, either. Also, you can't dim them. Dim an incandecent just 5% and it will last many, many years. Even the commercial lighting industry has abandoned them.

Enlightened countries have recycling schemes with the cost built into the purchase price. Evacuate the gas and reclaim the mercury and phosphor, same as for traditional fluorescent tubes. (Reclaim to keep them out of the environment, not because the amount reclaimed is commercially viable.) Regarding broken lamps, the official policy here is that the quantities of mercury and beryllium etc are so low that the risk is negligible in domestic situations.

Dimmable tube fittings are available if you want them, as are dimmable CFLs. Their main problem is that the color temperature doesn't shift as they dim, as people have come to expect.

"Even the commercial lighting industry has abandoned them"... you must be referring to GLS incandescents. The last use I had for them was in Eastern style lanterns, the ones with holes cut in them to cast patterns on the walls. Now I use the halogen replacements (GLS style envelope containing a quartz glass halogen lamp). They are more efficient, last longer, and the filament is smaller so it casts more sharply defined patterns.

[Don Hills]

Originally Posted by PlasticIsGood

LEDs are good if you can do without parts of the spectrum. Experiments continue in greenhouses but I think benefits are weak. High pressure sodium is cheaper for full spectrum, but plants can cope with no green and reduced blue for much of the time. ...

LED panels for hydroponic gardening are very common. They use red and blue LEDs. They don't use green because, surprise surprise, clorophyll is green and reflects green light instead of absorbing it.

[sofaspud]

Enlightened countries

That's a pun, right?