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There are many different kinds of LED bulbs for home lighting. Most of them are not very good yet, producing few lumens per watt.
One short term goal has been to produce about 100 lumens of light in a downlight for 1 watt of electricity.
100 lumens would be enough for a downlight in a closet.
400 lumens would be enough to light an entranceway or a kitchen sink.
600 to 800 lumens would be enough for general purpose lighting.
Cool white LED bulbs usually put out about 50% more light for the same number of watts than warm white LED bulbs.
There are many prototypes that produce 200 lumens per watt under stringent conditions. However, I had yet to see a bulb for home use that produces even 100 lumens for 1 watt until I saw this the other day.
http://www.amazon.co.jp/gp/product/i...8871&s=kitchen
The bulb is really small, E17 socket size, with the head about the size of a pingpong ball. The daylight one above produces 550 lumens for 5.4 watts. The warm white one I bought produces 410 lumens for 5.4 watts, indistinguishable from the 40 watt incandescent it replaced. This light is on at least 12 hours per day, so saves about $4 per month in electricity for a payback time of about a year, and after that, I expect it to save about $50 a year for the next 10 years until it burns out, an annual 100% return on investment. But the electricity rate in Japan is about 30 cents a kilowatt hour, so your return will be less if your rate is lower.
This model came out in the last month and so was quite expensive, about 3,500 yen, $40. However, hundreds of LED factories are coming online now, and prices should drop to the $10 to $20 range in one to two years. Once the price drops to $10, the payback for me would be about 3 months.
Because of the many, many different kinds of LEDs, it would be useful to buy one now and learn all the issues of voltage, lumens, color, wattage, heat issues, cost, etc., but mostly how it actually looks when in use in your home. What it looks like in the store is usually not a good guide. After playing with it for a year or so, you will be prepared to make a good choice when the prices drop. You will only need to replace the lights you leave on for many hours a day; the rest can just be left as they are since there will be little advantage in changing them to LEDs if they are hardly ever on. Look around on eBay. You will be surprised at the huge variety of forms.
The LEDs in Japan have been improving by the month, so I would not be surprised to see something like 200 lumens per watt in a couple of years, the equivalent of a 75 watt bulb for 5 watts.
Unfortunately, I have been checking all the lights for sale on Amazon in the US, and so far, I cannot find anything comparable to the above Toshiba light. The lumen outputs per watt are much lower.
Note that when installing an LED in any fluorescent light fixture that has a ballast/starter, the ballast/starter must be removed by an electrician or else the LED will instantly burn out.
http://www.amazon.com/LED-96-Lumens-...7844432&sr=8-1
If you know any electricians who need work, you might want to point out the kind of labor it will take to replace the millions of fluorescent lighting fixtures or remove all those ballasts.
In our office building, they are considering that a regular fluorescent light is about $10 and must be replaced annually, and therefore, if an LED replacement is about $100 dollars but lasts 10 years, the cost is actually already the same. There will be savings in not having to have the lights replaced every year, not to mention cutting electricity use in half, and reducing the waste heat from the lighting that the air conditioning has to remove from the building. On our floor alone, there are 400 fluorescent lights, and we guesstimated that changing them over to LEDs would save in electricity the equivalent of the salary of one staff member. Final tweaks in color quality and brightness are all that remain, so it is time to test a few for a year, and more the year after that, so as to be ready for the huge changeover beginning about 2012?... just in time for the hyperinflation... might as well expend the cash you have on something you need...
One short term goal has been to produce about 100 lumens of light in a downlight for 1 watt of electricity.
100 lumens would be enough for a downlight in a closet.
400 lumens would be enough to light an entranceway or a kitchen sink.
600 to 800 lumens would be enough for general purpose lighting.
Cool white LED bulbs usually put out about 50% more light for the same number of watts than warm white LED bulbs.
There are many prototypes that produce 200 lumens per watt under stringent conditions. However, I had yet to see a bulb for home use that produces even 100 lumens for 1 watt until I saw this the other day.
http://www.amazon.co.jp/gp/product/i...8871&s=kitchen
The bulb is really small, E17 socket size, with the head about the size of a pingpong ball. The daylight one above produces 550 lumens for 5.4 watts. The warm white one I bought produces 410 lumens for 5.4 watts, indistinguishable from the 40 watt incandescent it replaced. This light is on at least 12 hours per day, so saves about $4 per month in electricity for a payback time of about a year, and after that, I expect it to save about $50 a year for the next 10 years until it burns out, an annual 100% return on investment. But the electricity rate in Japan is about 30 cents a kilowatt hour, so your return will be less if your rate is lower.
This model came out in the last month and so was quite expensive, about 3,500 yen, $40. However, hundreds of LED factories are coming online now, and prices should drop to the $10 to $20 range in one to two years. Once the price drops to $10, the payback for me would be about 3 months.
Because of the many, many different kinds of LEDs, it would be useful to buy one now and learn all the issues of voltage, lumens, color, wattage, heat issues, cost, etc., but mostly how it actually looks when in use in your home. What it looks like in the store is usually not a good guide. After playing with it for a year or so, you will be prepared to make a good choice when the prices drop. You will only need to replace the lights you leave on for many hours a day; the rest can just be left as they are since there will be little advantage in changing them to LEDs if they are hardly ever on. Look around on eBay. You will be surprised at the huge variety of forms.
The LEDs in Japan have been improving by the month, so I would not be surprised to see something like 200 lumens per watt in a couple of years, the equivalent of a 75 watt bulb for 5 watts.
Unfortunately, I have been checking all the lights for sale on Amazon in the US, and so far, I cannot find anything comparable to the above Toshiba light. The lumen outputs per watt are much lower.
Note that when installing an LED in any fluorescent light fixture that has a ballast/starter, the ballast/starter must be removed by an electrician or else the LED will instantly burn out.
http://www.amazon.com/LED-96-Lumens-...7844432&sr=8-1
If you know any electricians who need work, you might want to point out the kind of labor it will take to replace the millions of fluorescent lighting fixtures or remove all those ballasts.
In our office building, they are considering that a regular fluorescent light is about $10 and must be replaced annually, and therefore, if an LED replacement is about $100 dollars but lasts 10 years, the cost is actually already the same. There will be savings in not having to have the lights replaced every year, not to mention cutting electricity use in half, and reducing the waste heat from the lighting that the air conditioning has to remove from the building. On our floor alone, there are 400 fluorescent lights, and we guesstimated that changing them over to LEDs would save in electricity the equivalent of the salary of one staff member. Final tweaks in color quality and brightness are all that remain, so it is time to test a few for a year, and more the year after that, so as to be ready for the huge changeover beginning about 2012?... just in time for the hyperinflation... might as well expend the cash you have on something you need...
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