LEDlight

One of the rooms in our house has the world's worst light bulb.   It's environmentally-friendly, lasts forever (unfortunately) and cost far more than it's worth.   It's also incapable of giving off much in the way of real light.  And it takes about five minutes to warm up to its full strength.

So much for being nice to Nature.  We've reverted to old style light bulbs in the rooms in our house where we actually live (the room mentioned above is a spare bedroom) because it's almost impossible to read by the ones that e-f (environmentally-friendly).   I like to use 150 or 200 watt bulbs in the main rooms, but do you think I can find them in the supermarkets, or lighting shops?   Occasionally they turn up, but for the most part the range of light bulbs of the e-f kind barely goes over 100 watts - or what it claims to be 100 watts.   And every so often they literally burn themselves out.  Creates a stink, and isn't particularly safe.

Which leads me to led light bulbs. (I mean LED light bulbs, but the link won't accept the capitalization, for some reason.) Supposedly, for various reasons these are a lot more efficient and cost-effective than incandescent lamps (the kind I still prefer).   On Wikipedia the comparison between an incandescent lamp and an LED is firstly cost ($2 versus $20); electricity usage (60 watt compared to 9 watt); lumens - ie the amount of light given out - is 660 compared to 900; which should make them a much better deal for our spare bedroom, you'd think: the spare-bedroom guest might even be able to read in bed.
Lumens per watt is 11 compared to 100.  Lifespan is 2,000 hours versus 25,000 hours.  I'm not sure that we ever get 2,000 hours out of our incandescent lamps, but let's assume we do.  Bulb cost over ten years - $22 compared to $20.  Energy cost over 10 years at 15c per kilowatt hour: US$197.10 vs $29.57.  Which means the total financial cost is US$219.10 compared to $49.57.

All sounds good.  The initial problem is that I have to believe, when I see a light bulb in the supermarket that costs $20 (nearly $24NZ) that it's going to be worth my while to buy.  These figures would seem to indicate that it is.  I'll let you know in ten years, when my LED one finally gives up the ghost....(the one in the spare bedroom will probably still be going as well, because we hardly ever use it!)