The GOOD LED Light Bulb thread

[explanade]

After following this thread, I went to HD and bought a few LED bulbs. They had a $5 off sale.

Then I got to thinking... my house is all electric, and an incandescent bulb produces 95% heat, so I might as well use up those cheaper incandescent bulbs in the winter months. I'll save the LED for the summer.

If and when I get to an age when I start considering not buying green bananas, I think a 20 year LED bulb will be a hard sell.

But bulbs are not the most efficient way to heat your house. You're using more electricity to reach a given level of brightness.

Plus those LEDs are suppose to last as long as 20 years so you're not saving much out of their life by waiting a few months.


With $5 off the cheapest LED bulb was $5?

 

[travelover]

........ my house is all electric, and an incandescent bulb produces 95% heat, so I might as well use up those cheaper incandescent bulbs in the winter months. ..........

Is your house heated with resistance heating or a heat pump? There is a big difference in efficiency. An incandescent bulb is just a resistance heater.

 

[calmloki]

OT here, but CostlyCo has 4 packs of little bitty 60W equivalent CFLs, 2700K color (warm color rather than hard white) for $4.99 with a $2 discount applied at the register. $3/pack? $0.75/bulb? After buying 25 4-packs of incandescents @ $1.28 I splurged on 15 packs of the CFLs. At about twice the price of the cheapest resistance bulbs they make sense, burning 1/4 of the juice and liable to last at least twice as long, if not the vaunted 10,000 hours marketing claims....

I now return you to discussion of the bulbs that cost, at best, more than six times that amount and burn the same amount of juice as the CFLs.

 

[TOOLMAN]

Is your house heated with resistance heating or a heat pump? There is a big difference in efficiency. An incandescent bulb is just a resistance heater.

I have a heat storage system. I noticed they were popular in Europe, so when I built my house I imported them.
Basically it heats up a box or rocks during off peak rates then it releases the heat during on peak.

 

[travelover]

I have a heat storage system. I noticed they were popular in Europe, so when I built my house I imported them.
Basically it heats up a box of rocks during off peak rates then it releases the heat during on peak.

OK, so this is resistance heating with a twist. The heat from the light bulbs would be paid for at the rate in force when you needed the light.

 

[travelover]

.........I now return you to discussion of the bulbs that cost, at best, more than six times that amount and burn the same amount of juice as the CFLs.

Are you saying that LEDs have the same efficiency as CFLs? I don't think so.

Compare: LED Lights vs CFL vs Incandescent Lighting Chart

 

[TOOLMAN]

OK, so this is resistance heating with a twist. The heat from the light bulbs would be paid for at the rate in force when you needed the light.

Makes sense. BTW the heat storage is 220v and saved us about 2k per year for the last 20 years vs resistance heating alone.

 

[travelover]

Makes sense. BTW the heat storage is 220v and saved us about 2k per year for the last 20 years vs resistance heating alone.

I believe it, electrical resistance heating is about the most expensive way to heat.

 

[calmloki]

Are you saying that LEDs have the same efficiency as CFLs? I don't think so.

Compare: LED Lights vs CFL vs Incandescent Lighting Chart

The equivalent LEDs I've looked at are pretty close in electric consumption to the CFLs.
For instance:
Cree 13.5W TW Series Soft White LED Bulb - Smart home - CNET Reviews

Or the first LED in this thread:

Home Depot Ecosmart 9 Watt (65W) BR30 Soft White (2700K) LED Flood Light Bulb
650 Lumen, Life 22.8 years based on 3 hrs./day
SKU184-441, UPC 887437000694, $15.88 and still the same price today in HD stores

The FEIT CFLs I referenced from Costco:
13W 900 Lumen, average life 10,000 hours (@ 3 hours/day = 9.1 years) 2700K, advertised as RoHS compliant, contrary to your chart's assertion on CFLs. $0.75/bulb

So the Ecosmart LED puts out 72% of the lumens but only uses 69% of the energy and lasts 2.5 times as long? But costs 21 times as much?

If instant on is really important and your bulbs are not at risk and they are located in really awkward locations for changing and you believe the LED lifespan claims then by all means have at 'em.

I'll defer to Fermion's comment early in the thread:

Not that it probably makes a difference or many of you care, but it is the electronics that are failing in the LED bulbs, not the LED element itself. I opened up 7 failed bulbs and found the LED elements to be perfectly fine. They are wired as a series string of about 12 LEDs per string...sometimes two parallel strings of 12 LEDs. It takes about 22 volts for most of these to get to the knee in the diode conduction curve and they run on around 36V DC.

The buck converter which takes in 115VAC and outputs the 36V DC uses things like capacitors with a 1000 hour or 2000 hour typical life for rated spec (and this is usually for moderate temperatures...shorter life at higher temps). All of the units were potted and I was too lazy to try and dig out the potting to figure out exactly what failed, but I am guessing it was these capacitors degrading, causing some sort of change in the buck converter. This either blew the converter chip or perhaps popped a non-resettable fuse in the lamp guts.

Sorry if this was TMI. I love the LED lights but I buy them expecting only to get 2000 to 3000 hours out of them. I am going to make a huge 5000 watt LED spotlight someday out of all of these broken elements.

 

[samclem]

I have a heat storage system. I noticed they were popular in Europe, so when I built my house I imported them.
Basically it heats up a box or rocks during off peak rates then it releases the heat during on peak.

I recall reading about a system some guy had rigged up that used the waste heat from his AC unit to heat a >big< bin of rocks or water drums. The bin was under the house and well insulated. The bin of stuff got warmer and warmer thoughout the summer as the AC ran. Other waste heat (from clothes drying, etc) could also be added to the bin. In the winter, he extracted heat from it.
Seemed like a good idea in principle, but the payback period would likely be awfully long. It might be practical for a superinsulated home. With many of these schemes (earth tubes, etc) the trick is to control moisture and to avoid the growth of nasty molds and organisms inside the storage media.

 

[NW-Bound]

It's tough having enough thermal storage for a seasonal cycle. Most commonly, one can have enough storage just for a diurnal cycle.

I once entertained the idea of having my A/C exchanging the heat with my swimming pool instead of the air. Here in the arid SW, pool water tends to be cool (70F) due to evaporation, even when the air temperature might be more than 100F. Hence, there is the desire to warm the pool up, plus exchanging heat with a cooler body than air would help efficiency.

So, my A/C is a 5-ton unit, running about 10 hours out of a 24-hr period. It will need to sink 5 tons * 12,000 BTU/hr/ton * 10 hrs/day = 600,000 BTU/day.

Dumping the above heat into a 25,000-gal pool will heat it up 3 deg F a day. In open air, I do not know how high the water temperature will get until it gets to a stable point, where heat gain equals heat loss. However, I am sure that the A/C will warm it up very nicely, and if it is too hot, I can always run the aerator to cool it down by evaporation.

I never looked further to experiment with this. But suppose I manage to insulate the pool to use it for thermal storage. At a rise of 3F/day, it would be boiling before the summer is over!

Water has a much higher specific heat than solid materials such as rock, and the fluidity also helps circulating the heat. It is going to be very difficult to use a bed rock for seasonal thermal storage. It would have to be huge.

 

[TOOLMAN]

It's tough having enough thermal storage for a seasonal cycle. Most commonly, one can have enough storage just for a diurnal cycle. I once entertained the idea of having my A/C exchanging the heat with my swimming pool instead of the air. Here in the arid SW, pool water tends to be cool (70F) due to evaporation, even when the air temperature might be more than 100F. Hence, there is the desire to warm the pool up, plus exchanging heat with a cooler body than air would help efficiency. So, my A/C is a 5-ton unit, running about 10 hours out of a 24-hr period. It will need to sink 5 tons * 12,000 BTU/hr/ton * 10 hrs/day = 600,000 BTU/day. Dumping the above of heat into a 25,000-gal pool will heat it up 3F a day. In open air, I do not know how high the temperature will get until it gets to a stable point. However, I am sure that the A/C will warm it up very nicely, and if it is too hot, I can always run the aerator to cool it down by evaporation. I never looked further to experiment with this. But suppose I manage to insulate the pool to use it for thermal storage. At a rise of 3F/day, it would be boiling before the summer is over! Water has a much higher specific heat than solid materials such as rock, and the fluidity also helps circulating the heat. It is going to be very difficult to use a bed rock for seasonal thermal storage. It would have to be huge.

We are getting off topic but I found these figures to be very close to my real wold numbers.

 

[NW-Bound]

Surely, if one can make use of the time-of-day difference in electric rates, he will come out ahead.

Your chart shows an off-peak rate of $0.05/KWhr, and $0.11/KWhr on-peak. What I am paying is $0.07/KWhr off-peak, and $0.21 for on-peak. And in the summer, the $0.21 price is when I, along with the entire city, need to run the A/C.

Nobody has found an easy way to store off the "cool" that can be produced off-peak. I have looked at solar electric installation which would be ideal, but my house orientation is not suitable for it.

 

[Fermion]

Our house uses electric heat (mostly zoned heating with baseboards) so I replaced only the outside lights with LEDs at first (while LED bulbs were expensive). Like others noted, if you have a baseboard heater running in a room, you are not saving anything by having your LED light only consume 10 watts compared to a filament bulb 60 watts. The baseboard just has 50 watts less it needs to output. We live in the Northwest and so use a little bit of heat probably 8 months out of the year. Plus we have cheap hydro.

In the southern states, the LED would be especially good as you are running an AC to keep the house cool and so don't want that 50 watts of waste heat from a 60 watt incandescent.

 

[MichaelB]

Getting back on topic, can anyone recommend a LED equivalent for a dimmable indoor flood BR40?

 

[NW-Bound]

In the southern states, the LED would be especially good as you are running an AC to keep the house cool and so don't want that 50 watts of waste heat from a 60 watt incandescent.

I have used CFLs since forever. Have not bought any LED yet, though I have homebrewed LED lights for my motorhome for boondocking purposes.

The little LED module that puts out enough light as a 60W bulb is down to less than $1.50, in single qty. off eBay, with free shipping from Guangdong! Note that this is the LED assembly without any electronics for people who want to play with it.

 

[MichaelB]

We had very bad results with CFL (BR40 equivalent), losing 12 in less than a year. The manufacturer wouldn't make good on the warranty because we didn't have original receipts and packaging. If we can find LEDs for these, especially at the price level mentioned earlier, I definitely will keep original receipts.

 

[travelover]

The equivalent LEDs I've looked at are pretty close in electric consumption to the CFLs.
.........

Thanks for posting this, I thought LEDs were about 10 times as efficient as an incandescent and CFLs were about 4 times as efficient. My only experience with LEDs is in RVs were they make a whopping difference in battery life when camping off grid. There, I've just been using a simple voltage regulator to maintain a 12 volt maximum.

 

[Fermion]

I made my own RV led lights (didn't like the cheap plastic fixtures that RV stores sell) by taking 110VAC Sylvania flush mount ceiling lights and stripping out the 110VAC to ~36VDC buck converter circuitry (ie, clip two wires). I then wired in a potted DC-DC converter module that takes 10 to 32V DC input and can output up to 48V DC at 700mA (called the FlexBlock)

A011-D-V-700 FlexBlock - LED Supply.com

Works a treat. Before stripping down the 9 watt Sylvania fixture I measured the LED string voltage (was around 42VDC). I played around with resistor values until I found a light output that was pleasing. This was 38V output from the Flexblock which consumed 7 watts of input power (Flexblock set to output constant current of about 160mA). I ran the lamp and Flexblock for a few hours mounted to the RV roof while monitoring the temperature and it only went up a couple of degrees above ambient.

This is what they look like in the RV we are custom building:

 

[mike143]

Cree 6W (40W) $6.97 and 9.5W (60W) $9.97 at Home Depot 10-20-2013 - Slickdeals.net

 

[walkinwood]

Getting back on topic, can anyone recommend a LED equivalent for a dimmable indoor flood BR40?

I bought 2 Ecosmart BR40s from Home Depot about 9 months ago for the kitchen and am pleased with them.

 

[walkinwood]

Looks like it may pay to wait for LED bulbs that have the energy star label.

Light output depends on the bulb's spec, but is a minimum of 1,600 lumens for bulbs purporting equivalence to a 100-W incandescent bulb. Among the other criteria are color rendering index of at least 80, and a rated life of at least 25,000 hours...

A tale of two tests: why Energy Star LED light bulbs are a rare breed

 

[gozer]

Thanks for posting this, I thought LEDs were about 10 times as efficient as an incandescent and CFLs were about 4 times as efficient. My only experience with LEDs is in RVs were they make a whopping difference in battery life when camping off grid. There, I've just been using a simple voltage regulator to maintain a 12 volt maximum.

Many non-white LEDs are more efficient than CFL bulbs as you thought, but most of us want white light. Right now white LEDs and CFLs are running neck and neck. Improvements are being made for each color of led light (including white). Last I heard green was the current winner, it was blue before that.

I think RV lights mix yellow in with white to get more efficient light fixtures.
Since RV owners are used to 12v automotive type lights they seem to get away with this. Some RV owners complain that the light near the edges of the lit area has yellow dots. I haven't switched my RV over yet, so my only personal experience is playing with them in the store, which is already lit by fluorescent bulbs and may mask that kind of effect.

 

[samclem]

Many non-white LEDs are more efficient than CFL bulbs as you thought, but most of us want white light. Right now white LEDs and CFLs are running neck and neck. Improvements are being made for each color of led light (including white). Last I heard green was the current winner, it was blue before that.

I've thought about this, even before the white LEDs were available. It would seem that in something as large as a residential light bulb there would be plenty of room to include a mix of efficient color LEDs and blend the light together (a few layers of "frosted"/scattering glass?) to give a white light at the surface. Obviously this isn't practical or it they'd be doing it. Maybe it's the light losses/heat produced in the "mixing" process that makes it impractical.

 

[Fermion]

I think LEDS are just a tad more efficient than CFL, but they last longer (at least the light emitting part does) and are not as fragile. For RVs the other big advantage is they are usually lower profile and don't shatter.

The Sylvania LED home fixture I modified for RV use is only about 1 inch thick at the middle, including the bezel. This would be hard to fit a CFL in.