LED Light Bulbs

amirm

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A general warning to readers: Don't be tempted to overdo the upsizing. The fixtures are limited in wattage because of their limitations on heat dissipation. LED bulbs have much lower maximum allowable temperatures than incandescent bulbs and can overheat in limited wattage fixtures.
I used to worry about this in the past. But I find today's power supplies in LED bulbs to be far more efficient and run surprisingly cool. Our outdoor fixtures are open anyway so heat collection is not a problem. The limit they had for normal bulbs was likely due to immediate vicinity of the bulb getting too hot.

Even indoors with closed fixtures, the increased light is worth a potentially shorter lifetime. On that note, I have noticed that a new class of LED bulbs is coming to market from Philips that are much smaller and cheaper. The down side is that the Warranty is shortened considerably. I am shying away from these as I suspect they have reducing cooling and hence the reason they don't want to stand behind them as long.
 

astrotoy

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We've started buying the LED's from Costco. There have been instant rebates, so the price for the spot type bulbs (downward focussed light for recessed fixtures) is around $10. They have been replacing the CFL bulbs as they go out. We have not had great luck with the CFL's. Besides taking some time to reach full brightness (not so good as we get older and can't see as well), the lifetime advertised (up to 10x a regular incandescent) doesn't seem to be holding up (unless the operative words are "up to"). The LED's are instant full brightness and are advertised as dimmable - which I haven't tested yet.

One thing good about Costco is they basically have a lifetime, no questions asked guarantee, so if I get early failure, I can bring them back.

Anyone have issues with interference with their audio systems with rf or other negative effects? I put a couple of LED regular light bulbs in lamps in the listening room and they seem to be noise free.

Larry

PS - when I look at the wattage capacity of a lamp, I see something like 60W or 75W. If an LED is equivalent of 100W but only uses 15W, is the 15W the operative number or the 100W for the wattage capacity. I thought it was the former.
 
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treitz3

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Anyone have issues with interference with their audio systems with rf or other negative effects? I put a couple of LED regular light bulbs in lamps in the listening room and they seem to be noise free.

Hello, Larry. Good question. :) I haven't noticed any additional noise or artifacts in my listening room with the LED's installed (no dimmer).

Tom
 

astrotoy

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Hello, Larry. Good question. :) I haven't noticed any additional noise or artifacts in my listening room with the LED's installed (no dimmer).

Tom

Thanks, Tom. I just modified my post with another question on capacity. Larry
 

amirm

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One thing good about Costco is they basically have a lifetime, no questions asked guarantee, so if I get early failure, I can bring them back.
Ah, I had forgotten about that. I have never returned anything to Costco. Do you need to have the original receipt?

Anyone have issues with interference with their audio systems with rf or other negative effects? I put a couple of LED regular light bulbs in lamps in the listening room and they seem to be noise free.
It is perfect for me but I have a Crestron lighting system with high quality dimmers so not representative of other uses.

PS - when I look at the wattage capacity of a lamp, I see something like 60W or 75W. If an LED is equivalent of 100W but only uses 15W, is the 15W the operative number or the 100W for the wattage capacity. I thought it was the former.
15 watt is the number. Its light output is the same as 100 watt (give or take) but power consumption and heat dissipation is 15 watts. So if a fixture says up to 60 watts, you can go way above and still be OK with LEDs.
 

GaryProtein

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It has been high time (for at least thirty years) to sell light bulbs by the LUMEN NOT the WATT.
 

astrotoy

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Ah, I had forgotten about that. I have never returned anything to Costco. Do you need to have the original receipt?


It is perfect for me but I have a Crestron lighting system with high quality dimmers so not representative of other uses.


15 watt is the number. Its light output is the same as 100 watt (give or take) but power consumption and heat dissipation is 15 watts. So if a fixture says up to 60 watts, you can go way above and still be OK with LEDs.

Thanks, Amir. A 60 watt LED should be extremely bright! My experience at Costco is no receipt is needed. Basically, they look up the item in their database and then see whether there is a record of you purchasing it. Then they just give you back your money including taxes, minus any rebate that you got when you bought it. The only exceptions are electronic goods, like TV's and computers where there is a time limit - at least several months. This happened because people were bringing in their 4 year old computers to upgrade (for free basically) to the new model. For those, they also give a 2 year guarantee - I think you can return it if it fails within that time.

Larry
 

Don Hills

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Jun 20, 2013
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I used to worry about this in the past. But I find today's power supplies in LED bulbs to be far more efficient and run surprisingly cool.

Depends on the brand / model...
http://blog.lifx.co/2014/02/07/how-hot-are-led-light-bulbs/

Our outdoor fixtures are open anyway so heat collection is not a problem. The limit they had for normal bulbs was likely due to immediate vicinity of the bulb getting too hot.

The limit is usually set by the maximum temperature allowed for the wiring in the socket - typically 90C. Sometimes it's set by the fitting's plastics or paint.

Even indoors with closed fixtures, the increased light is worth a potentially shorter lifetime. On that note, I have noticed that a new class of LED bulbs is coming to market from Philips that are much smaller and cheaper. The down side is that the Warranty is shortened considerably. I am shying away from these as I suspect they have reducing cooling and hence the reason they don't want to stand behind them as long.

Note from the above link how hot some small LED lamps run, even in free air. For longevity, most manufacturers recommend keeping the electronics temperature to 40 or 50C. Running hotter cooks the electrolytic capacitors in the power supply and shortens their lives.
LED lamp temperature ratings are normally set with the lamp mounted in free air or in a natural flow situation, such as a shade open at top and bottom. An enclosed fitting adds thermal resistance between the lamp and ambient. For example, take a 60W lamp in enclosed fitting, ceiling mounted. The ambient temperature around the fitting can be 30C or more, and with a limit of 90C the temperature rise will be 60C. Conveniently, this is a thermal resistance (temperature rise) of about 1 degree C per watt. A 12W LED (60W equivalent) will run 12C hotter in the 1C/watt fitting than free air. Putting a brighter LED lamp in the fitting, say a 20W (100W equivalent) will run 20C hotter. Every 10 degrees C increase in temperature halves the life of an electrolytic capacitor. Hence my original warning, not to overdo the uprating when replacing GLS with CFL or LED. As you say, you choose between brighter light and longer life.
 

DonH50

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I agree with Don (natch). There have been many articles in engineering magazines showing drastically reduced life in can-mounted LED replacement bulbs.

Cree and a couple of others have announced new models that do not have external heat sinks, at least not the big fins, and claim they run cooler. I have not seen any test results on those yet.
 

Johnny Vinyl

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Thanks, Amir. A 60 watt LED should be extremely bright! My experience at Costco is no receipt is needed. Basically, they look up the item in their database and then see whether there is a record of you purchasing it. Then they just give you back your money including taxes, minus any rebate that you got when you bought it. The only exceptions are electronic goods, like TV's and computers where there is a time limit - at least several months. This happened because people were bringing in their 4 year old computers to upgrade (for free basically) to the new model. For those, they also give a 2 year guarantee - I think you can return it if it fails within that time.

Larry

You have 3 months to physically return electronics. The remainder of the warranty (1 year-9 months) is covered by their Concierge service (a 1-800 number).
 

Kingsrule

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If you dim an LED bulb, say to 85% permanently, will it last even longer?
 

garylkoh

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It has been high time (for at least thirty years) to sell light bulbs by the LUMEN NOT the WATT.

As I just moved, I had to replace every light bulb in the new flat. On my trips to Ikea, Home Depot, Lowes and Costco - most of the bulbs were rated by Lumen, not the Watt which made shopping very much easier. Color temperatures were also prominent.
 

Kingsrule

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Really do not understand your response...
 

zztop7

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Really do not understand your response...

LED is a Light Emitting Diode that needs a >regulated power supply< to limit current [part of the LED]. This power supply almost always fails before the diode [the light emitting part]. If your bulb has a very high quality power supply, then the 85% should not make a difference. If your bulb has a cheap power supply, it will have a shorter life than advertised no matter what. 85% may make a small difference [?] in longevity of the cheap LED.
zz.
 

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