I really don't know what the cost per KW is here (never looked at the bill, wife pays them) but that sounds about right. The reason I put 19 of them in was to save energy cost. Granted the other 17 don't run nearly as much as the ones I had to replace. Kitchen lights run next on the longest time but I doubt that they run more than 6 hours per day. These two are over our computer table so the come on first thing in the morning till last thing at night. I think I got my monies worth from them and you are correct that they cost around $25 each when I bought them.Lets do a little cost analysis to see if Gary saved any money on his 31,000 hour period he used his LED bulbs.
I don't know what Gary paid for those bulbs 5 years ago, but I am going to suggest he paid about $25 each. LED bulbs cost a lot more back then.
So he got 31,000 hours out of them, that would be about 30 standard bulbs that he could have bought for about $0.50 each. So he is in the hole about $10.00 on the costs of the bulb by my way of thinking. Now only Gary can tell us how much trouble it would have been to change out those 30 standard 1000 hour bulbs and whether that would be worth anything to him, but so far he is $10.00 in the hole in buying the LED bulb.
Now lets figure out how much electricity Gary saved with the 12 watt usage 60 watt equivilant LED bulb.
First lets figure how much the 30 standard bulbs would have cost to run. Lets see, 60 watts is .06 Kilowatts X 31000 hours = 1860 KiloWatt Hours. Lets say Gary pays $0.10 per KiloWatt Hour. So Gary would have payed $186.00 to run the 60 watt incandescent bulbs that 31,000 hours.
Now lets figure the LED bulbs. Gary said they used 12 watts. Newer bulbs use a bit less, but that seems about right for bulbs of that era.
12 Watts is .012 Killowatts. X 31,000 hours = 372 KiloWatt Hours. X $0.10 per Kilowatt hour (guessing here as to what Gary pays, but I doubt he pays any less than this) = $37.20 for electricity for the LED bulb. Whoa now! that is a huge saving in electricity. $186.00 - $37.20 = $148.80 in electrical savings, and now subtract the $10.00 that the bulb cost over the incandescent bulbs yields an overall savings of $138.80
Multipy the $138.80 by how ever many of these bulbs Gary had, and we are talking some real money.. Note that if the cost of electricity is more than the 10 cents and the fact that a good Cree bulb is about $9 at Home Depot, and that the new bulbs are 10 watts consumption for 815 lumens of light and your savings will be even more. Anyway you figure it, LED bulbs can save a pot of money, if they are used much.
Gary please correct me if anything doesn't look right in the figures or assumptions.
Mine were cluster of about 8 LEDs but none of them quit working, they just got dim.Many led bulbs, especially older ones, are clusters of led's.
Over time, as a few burn out, the bulb would put out noticeably less light.
So far, I am very pleased by the Cree brand, we shall see how well they hold up long term.
How long is a piece of string? When talking about how long an LED lamp will last, that certainly seems to be the state of the question.
Manufacturers of LED lamps, which many regard as the next generation of lighting, destined to eventually replace today痴 incandescent and compact fluorescent lighting sources, make wild claims as to product life.
Typical incandescent bulbs last 1,000 to 2,000 hours. But in speaking about LED replacements, lamp life is routinely quoted as 25,000 to 50,000 hours. Long lamp life, and the reduced power used to create the same amount of light, is what makes this technology so promising.
But what does a 25,000-hour life mean? As it turns out, no one is quite sure yet. The definitions surrounding LED lamps, a nascent technology, are still being made up as we go along.
One thing we do know: It means something different than when people think about the life of a regular light bulb.
When it痴 said that a standard light bulb will last 1,000 hours, that is the mean time to failure: half the bulbs will fail by that point. And because lamp manufacturing has become so routine, most of the rest will fail within 100 hours or so of that point.
But LED lamps don稚 澱urn out. Rather, like old generals, they just fade away.
When a manufacturer says that an LED lamp will last 25,000 or 50,000 hours, what the company actually means is that at that point, the light emanating from that product will be at 70 percent the level it was when new.
Why 70 percent? Turns out, it痴 fairly arbitrary. Lighting industry engineers believe that at that point, most people can sense that the brightness isn稚 what it was when the product was new. So they decided to make that the standard.
Of course, brightness is subject to the old frog in the boiling water syndrome. I知 sure that most people won稚 even notice the lower level then, if they致e lived with the same bulb for its entire life. (How many owners of rear projection DLP TVs only realize that a TV痴 image has dimmed once they replace the bulb?)
If nothing else in the lamp fails, like its electronics, the product will continue to work until it becomes really dim. But some engineers are proposing a way to get around even that.
Their idea is that once the LEDs start to emit less light, increase the power to each one to increase its brightness. Unfortunately, that will also diminish the life of the lamp.
Good idea, or bad? 典he utilities really don稚 like this idea, Fred Welsh, a Department of Energy consultant, told me on Thursday at a lighting conference sponsored by his federal agency.
Not only would contractors need to use thicker cables, but the utilities would need to create more power, partially negating the appeal of LED lighting in the first place.
But still, it痴 in its early days, and no one yet knows how this will be settled, or how the consumer will be educated to think about 澱ulb life in a different way than they have for the past 130 years. If consumers are going to switch to this new lighting technology, it痴 an issue that needs to be settled.
And if it isn稚? 典his is a potential black eye for the industry, Mr. Welsh said.
Our home, which is 13yr old, has 41 recessed lights in ceilings that take the 65w flood light. Several years back I switched out about 1/2 of them - all in lower level- with CFL's. The wife hated them for the slow warm up when you turn them on. Now I'm going back and changing out the whole 41 of them with LED's. I started with Westinghouse brand @ 750 lumens @ $7.50 ea. from Menards. I find that the light from those are harsh or too bright white.
I just ordered from the net, another dozen @$5.50 ea @ 650 lumens Great Value brand hoping they will tone it down some. Both bulbs are rated @ 9w
If this don't do the trick, I'll have to start looking into dimmers.
In some places like the stair well, the bright bulbs are great. But having 10 of them on in the kitchen is just way too bright, almost like eating on a stage.