John Wolfram makes an excellent point. I've been avoiding those kind of lights for precisely that reason. In my house though there's not one
incandescent light. For my work spaces I like a cool or daylight light and that's inefficient to do with incandescent, even with the modern ones with a halogen lamp inside: There used to be special "northlight" bulbs for artists with a blue glass envelope and you needed about twice the power rating to get the same amount of usable light.
Other lights are a mix of cool or warm, depending on what was to hand and where they are fitted. My partner prefers the warm one for a bedroom light. In the kitchen I have a 4000K 4ft fluorescent tube replacement which uses less power than the original 4ft tube did to give more light, it doesn't have a starter (it comes with a plug-in "starter replacement" which I guess simply connects the power to it) and has the added advantage of instant full power light just like the other LEDs.
Going back to Paul's original point about altering other, much more power-hungry aspects of your life such as using a washing line or clothes rack vs. using an electric
dryer, or washing up by hand in a sink and putting the dishes on a drainer vs. using a dishwasher: I think the point is that swapping out the lights is a low-effort thing that most anyone can do at more or less zero inconvenience. Making those other changes would have much more effect but many people don't do that because they don't want the extra effort.
There is one aspect of
LED lighting where I can see a definitive benefit in electricity cost and that's traffic signals. Some years back they began converting all the traffic signals in the UK to LED lamp units. The old signals used a 250W incandescent bulb in each of the 3 lamps (I know because I asked a chap who was changing out a bad bulb once). Consider a simple 4-way cross road. In the UK that will have 3 signals facing each direction: one either side of the road at the stop line, and one on the opposite side of the road so you can see it when parked at the line. That's a total of 12 signals on that one junction, and all of them have 1 light illuminated 24/7* for an ongoing consumption of 72KWh per day, or 26,280KWh per year for just ONE road junction. 26MWh of energy for ONE road junction!
Now consider the same junction with LEDs. Even if the LED lamps are 25W which I doubt, that would still cut the power consumption by 90%.
It's not the same everywhere as the lights differ: for example, I believe US rail signals use a mere 35CP bulb due to clever design of the lamp.
However I found this
webpage about traffic signals in the
city of Yakima. They had 100W bulbs in their signals and their LED replacements are 15W, and the bottom line is that they cut the energy use per 100 intersections by about 80%.
* OK in the UK they have a red+yellow phase, but that just makes the consumption higher. Other places only have 1 lamp lit at a time
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