Thursday, December 19, 2013

Alternate Lighting Schemes. LEDs, and Fluorescents.

Most of you probably have the compact fluorescents in your homes by now.  And now with the advent of LED bulbs are contemplating them as well, but with a $23-40 price tag, are also contemplating the survival rates of snowballs in Texas. This is not a propaganda piece to change your mind, but a couple of pages of information on the topic based on my experiences.  I am a technology buff, and a geek and have been following these advances for years. 

I was a fairly early adopter of the compact fluorescents when they came out.  I waited till the price was around $12/bulb and the displays showed they were putting out white light instead of brown.  After that I bought enough of them to re-bulb my house, and believing they would last the 7 years that was advertised.  Then the deployment problems started.

Compact fluorescents can’t be put on dimmer switches or on touch sensitive switches, which a surprising number of my fixtures were on.  Also I found that I didn't dare put two of them in the same fixture.  Each would emit a slight buzz, but two would buzz twice as loud, and out of sync.  This made my bathroom sound like it was infected by cicada’s on their 7 year mating cycle.  The result was I had to mix incandescents with fluorescents in the same fixtures.  

This created a storage problem, as now I had to stock both types of bulbs, with an excess of fluorescents, as I couldn't deploy as many as I had bought.  The secondary problem was the heat from the incandescent was boiling the electronics of the fluorescents, causing many premature failures.  This meant care must be made for the placement of the bulbs in a common fixture, mainly in the bathrooms where 4 bulbs are above the mirror.  First I put the fluorescents on the inside two, and the incandescents on the outside.  Logic being the outside bulbs would radiate half their heat outward.  This did not work well and premature failure of the fluorescents continued. My current configuration now has the fluorescents on the outside where they have better air flow to keep cool, and their failure rate has diminished.

A large part of the failure rate of the fluorescents has to do with manufacturing specs.  (made in China)  When I worked for CMC Energy Services, which is in the business of making homes energy efficient, I was given 4 compact fluorescent bulbs.  Their failure rate was 75% in 6 months.

Then there is the disposal problem.  The fluorescent coating requires mercury, and these bulbs should be taken to a recycle center for disposal.  That just sucks.  I am still kicking myself for that.  I did know, but didn't consider the mercury and that I was creating a pollution problem when I adopted the damn things wholesale.  Now that the fluorescent bulbs are under a dollar a piece, and 100 and 75 watt incandescent bulbs are outlawed, fluorescents are flying off the shelves, creating a waste stream catastrophe.  This may be over stated, because if you live in an area where your electricity is generated by coal, then the fluorescent bulbs are burning 75% less coal to light, and thus 75% less pollution in the air, mercury included.  The fluorescent bulbs probably are still better for the environment overall, providing they last the 7 years as promised.  I don’t think any of mine have, but some have lasted many years.  

There is also a dimming problem.  Fluorescents lose about about 20% of their brightness after 3 years average usage. 

For over 20 years, I have been following the development of LED lighting.  Everyone in the lighting business knew this was where lighting was going.  And it has been an arduous development process.  The lure was great, as the actual energy conversion to photons was very close to 100%.  But the lights were too dim.  The power conversion too big and too hot.  The number of light radiating elements too high and complicated, and LED light was too direct, like a laser, making them uniquely unsuitable for all round lighting.

Many years ago I saw a prototype LED lamp for chandelier lights.  It looked like a candle with white measles.  The bulb might put out the light, but you would never want to look at it.  I bought a string of blue LED lights for my Christmas tree.  Pretty yes, but when you walk through the room your eyes were constantly under assault by hundreds of blue lasers.  This is very distracting.  

So several years ago the only suitable LED lighting was for track lights.  They were $40 a piece, and I bought 2 of them.  The only problem with that the energy conversion process from house current, 120 volts AC to 5 volts DC creates a heat problem and to deal with the heat problem the bulbs are out sized to dissipate the heat.  This makes them ugly and in some lamp fixtures, impossible to deploy.  Also, this inefficient electric conversion means that LED’s burn 20% the energy of an incandescent as opposed to 25% for fluorescent bulbs.  The actual conversion of energy to light in an LED is an extremely efficient 98+%.  For fluorescents, this is about 10%, while incandescents convert only 2% of their input energy into light; the rest being lost as heat.

I will say, if you can fit them in your fixtures, my $40 track lights are excellent.  They burn bright, white, and after many years in a prominent spot, are still working.  I am well pleased with them.

But LED bulbs providing all round lighting, have proved elusive until recently.  In 2010, Sylvania announced their LED 60 watt (800 lumens) equivalent bulb.    But at $40 per bulb this is a hard choice when for the same price you can get a shopping cart full of incandescents.  I was tempted to buy ONE then as a test, but didn't.  The break-even point of energy savings was 5 years at that point, and frankly, I like my rooms bright, and in general don’t use less than 75 watts (1100 lumens).  And at that time I still had my two test LED track lights working.

Well it is three years later, and I think I can say, LED’s are here.  The size has improved somewhat.  My   The cost per bulb has dropped dramatically.  While the price point is not exciting, it does mean in my area of the world, where electricity is 15 cents/kilowatt hour, the payback on the 60 watt bulb is now a 1 year, down from 5.  After 3 years, the amount of electricity used by the LED bulb is under $2/year as opposed to $10/year for the incandescent.
Phillips 810 Lumen LED Light Bulb

But the main reason I am saying that LED’s have arrived is that the 75 and 100 watt equivalents are out.  They are not cheap either, at 20 and 30 dollars each, but both have the break-even point over the incandescents at just under 3 years.

Other things you should know.

LED bulbs are heavy.  Goose neck style lamps will droop with them, and lamps with long stems may be unbalanced.

Most LED bulbs will work on dimmer switches.  But that does not mean they will dim or light in stages.  The radiating elements of the bulbs are either off, or full on.  It does mean your dimmer switch will not blow out the energy converter.

Your heating bill will increase.  As your incandescents were providing excess heat, your heater didn't need to cycle as much.  But heating your house with electricity is the most expensive way to do it anyway, so there is a net savings overall.

You Air Conditioning bill will decrease.  Without your incandescents providing excess heat, your air conditioner won’t cycle as much.  This cost saving is almost a watt for a watt, effectively doubling the value of the LED bulbs.  A definite win-win situation.

LED Bulbs do not dim over time. This is noted by my personal observations and confirmed by Consumer Reports testing.  Fluorescents dim 20% in 3 years.  

Replace the heaviest used bulbs first.  My break even points are based on a light being on for 3 hours a day, but I replaced 2 specific bulbs now because that specific fixture is used 6 hours a day or more, reducing the break-even point to 18 months.

On Lumens

As watts becomes an irreverent method to measuring light output, the term lumens is coming into vogue.  Truth be told, watts were always just units of energy consumption, and was never a very accurate measuring the amount of light generated.  Higher wattage bulbs were more efficient, generating more lumens per watt.  A single 100 watt bulb generated almost as many lumens as 4, 40 watt bulbs.  Manufacturers are also playing fast and loose with the lumens and the “watt equivalency” on their packaging.  I have found this most egregious with regard to candelabra style lamps.  

I don’t propose you memorize the numbers.  But when I am comparing, I go by a 12-1 ratio.  1 watt incandescent generates 12 lumens of light.  Just keep in mind that this ratio is a curve, as 40 watts fall below this ratio, while 100 watts goes above it.  

But in general here are some numbers:
20 watts (candelabra)       165
40watts  (standard)           440
40watts (candelabra)        280
60watts (standard)            810
75watts  (standard)          1100
100watts (standard)         1600

On Kelvins
The last piece of information is concerning the spectrum of light the LED's are radiating at.  This is rated in Kelvins.  Scientifically this is the color temperature of the electromagnetic radiation emitted from an ideal black body is defined as its surface temperature in Kelvin.  

The current numbers seem to run from 2700K to 5000K.  2700K, which marketing is calling "cool white", is too brown for my taste.  I have 3000K and that is better with the color of the light being emitted.  But I really like how white the light is that is generated by the 5000K bulbs.  They are worth the extra cost in my book.  Especially for something that will last "forever".

No comments:

Post a Comment