Archive for the ‘LED lighting’ Category

The state of play in LED domestic lighting – late 2010

Saturday, November 20th, 2010

That technology always moves ahead is taken for granted, and rightly so.  That it moves more slowly than expected is frustrating:  was it Bill Gates who said that in two years you will see little apparent progress, but in 5 or 10 things (any aspect of emerging-manufactured products one can think of) there are transformations beyond our imagination?  To this pair of observations we should perhaps add a third:  as soon as an entrepreneur can explain a ‘vision’ to his venture capitalist, a PR person will be enlisted to advertise and promote the imminence of the breakthrough in question.

So it is in our LED industry, and also with electric cars, one of our other interests.  Breakthroughs are trumpeted some months, quarters or years before they become available.  In this blog we try to keep our feet on the ground – all pronouncements are treated with skepticism until we can buy and test the product on the general market.  Otherwise we could spend months in endless but premature speculation based on rosy press releases.

Here’s a short run-down of our progress in buying and testing, and day-to-day use of LED lighting products.

i. Fluorescent tube replacements.  The EarthLED DirectLED 48 inch 15W tubes in the laundry room are still running, after nearly a year at about 2 hours a day, as they should be.  We find them less bright than the 40W fluorescents they replaced, although the difference is small: leaving the plastic diffuser cover off the fixture gives equivalent output.  They are OK, but we won’t be adding more of this type.  Hopefully we’ll soon see a new generation of tube with 18 or 20W rating and higher-efficiency LED chips, a realistic drop-in replacement (apart from bypassing the ballasts of course) for the fluorescents.  As soon as I see some of these, they will be in our kitchen lighting unit, where 4x 40W fluorescents must be in use for about 6 hours every day.  These bulbs now retail for $60.

ii.  Recessed can fixtures.  Only a few months old, the Cree CR6 units sold by Home Depot as Ecosmart are fantastic.  Brighter than the old incandescents, dimmable (we need to, they are so bright!) and only 10.6W each.  We have two bedrooms installed now, for a total of 8 units; the family room will be upgraded next year and then we will slowly work through the house.  $50/unit is still expensive, of course.

iii.  Incandescent ‘A-style’ bulbs in screw-in holders.  We have two of the Pharox 300 60-Watt replacements (at 6 Watts); one’s for our outdoor light that’s on all night, with a daylight sensor switch, while the other is a bedside reading lamp.  Both seem a bit dim to be a 60-Watt replacement:  without measuring, it seems equivalent to a 40-Watt bulb, but the colour (warm white 2900K) is good, and provided they last for many years they will be a good investment, even at $30 each.

Apart from the above, there are still several types of bulb that we use around the house, but for which there is as yet no good LED equivalent.  The one I would most like to replace is the halogen double-ended tube, at 150 Watts we have one as a center light fixture in all the bedrooms.  In the past I encouraged the family to use these rather than the 4, 6 or 8 recessed can circuits surrounding them, but of course LEDs in the recessed fixtures are much more economical.  These bulbs have such a small size and thin envelope that it may take several years before LEDs are a viable alternative:  it would be difficult to pack many LED chips into that small a unit, and the heat generated would probably be a problem.

The second type of bulb is more promising.  We have a number of chandeliers, notably one above the stairs which is in use around 5 hours a day.  At present I only populate one of the three tiers of 6x 25W bent-tip candelabra style incandescents.  The LED bent-tip chandelier bulbs are currently advertised at around 3W, supposedly equivalent to a 15W incandescent, so hopefully the next generation will be around 5W and realistic replacements for 25W bulbs.

We also have a few night lights – four in all, at 4W.  When on for 24 hours, this amounts to about 400Wh per day, so it would definitely be worth using 0.8W LEDs, and these are indeed available.  I’ll be testing some in the near future.

So LED lighting technology advances, but slowly.  Of the products above, the EarthLED tube has been available for some years, as was the original Cree LR6, but both have come down in price 30% or more in the past year.  The Pharox 300 is new, and not only is it brighter than the A-style bulbs of 2009, its price is maybe half of those earlier products.  The underlying LED chips are becoming more powerful, and as manufacturing techniques and volumes increase, prices are in the midst of a significant downward curve.

We’re hoping that next year we will see a new generation of LED chips driving more powerful, less expensive bulbs, so our 25W bent-tip candelabra and perhaps some 100W A-style bulbs will be replaced, and maybe we’ll be able to tackle those 4x 40W fluorescents in the kitchen, the most energy-hungry fixture in the house when measured over a year.

LED top-hat replacement (CREE CR6)

Wednesday, September 1st, 2010

We just tried four of the new ‘EcoSmart’ recessed lights from Home Depot.  They are actually the CREE CR6, but offered at just under $50.  Very impressive!  A bit of a job to work out how to install them, as they incorporate the whole fixture including trim ring, rather than just the bulb, but the light output is way higher than the 16 year-old75W R30s they replaced, and they take 10.5W with a rating of 35,000hrs service.  There’s a longer write-up with some figures on the web site, but by all means check them out (the bulbs)!

LED store pulls fluorescent tube replacements

Thursday, January 14th, 2010

I have a note on www.kilowatt-house.com about experiences with a 4ft fluorescent tube retrofit with LEDs.  I concluded both from my wife’s opinion and measuring the lux that the LED tubes are not equivalent to the 32W fluorescents they replace, but in the end I left the diffuser off the fixture, and we are all happy with the amount of light in the laundry room.  The instant-on is a welcome improvement too.

However, I just checked on the Website where the tubes came from (1000bulbs.com), and they have stopped selling all LED tubes.  They reference the CALIPER tests (round 9 now) done by the DoE in ‘mystery shopper’ style.  CALIPER concludes that the replacement tubes are disappointing, both for initial light intensity, degradation over time and the problems of re-wiring fixtures to remove fluorescent ballasts.  The last point, re-wiring, is not difficult to do but I understand why they would consider it a problem.  I agree with the first point, although it’s quite usable in our application, and I wait with interest to see how our new tubes age.

It’s not clear to me why LED tubes are so difficult to make:  they should have less integration, density and heat problems than other types of bulb.  I am hopeful that as the semiconductor technology gets better, they will be able to use more powerful LEDs.  Maybe without giving up efficiency, so the 15W won’t become 20W!

Of the other candidates for LEDs in our house, we have very few conventional bulbs, I might get one for my bedside reading light.  Most of our high-use bulbs are:

1. HALO recessed ceiling fixtures.  The CREE LR6 is just the job here, but I won’t be buying many at ~ $90 a shot.

2. 150W double-ended halogen which are very compact:  I doubt we will see an LED in this format for a while.

3. Chandelier/torpedo 25W bent-tips, particularly a set of 6 (the fixture takes 18 but I don’t run them all) that is in the stairwell and on several hours a day.  The LED equivalents are getting to 1.7 W now, supposedly 15W equivalent, so we should see a 3W/25W equivalent in a matter of months… (hopefully!).