[ale] More on LEDs...
Michael H. Warfield
mhw at WittsEnd.com
Mon Aug 12 18:34:24 EDT 2013
On Mon, 2013-08-12 at 08:05 -0400, Jim Kinney wrote:
> If it says X watts and Y lumens, it's a safe bet that the average
> production run will hit those specs. What's harder to gauge is how
> many lumens is needed for a task. For that, I would take various bulbs
> on hand and test.
If it says "X" watts, I would take that as the power it is expected to
consume and less is better, all other things being held equal. I'm
going to give very little credence to "equivalent to ZZ watt bulb"
claims, as that can be much much too subjective. The hard numbers are
power consumed, lumens produced, color temperature and life expectancy.
The efficiency is rated in lumens per watt. The life expectancy is
rated in the age at which it retains 70% of it's output. Life
expectancy (for {C}FL's and LED's) is typically derated for a duty cycle
of 3 hours use per day (Kitchens? Seriously - get real - more like 12.
Bedrooms will probably never burn out. My office - 16 hours per day
min.). If the packaging doesn't have the "hard numbers" on it, then
it's "no sale" for my cart.
The things I pay most attention to are lumens out and color temperature.
A given number of lumens at one color temperature are NOT going to look
(subjectively) the same brightness as the same number of lumens at
another color temperature. The "cool white" (which is, ironically, a
higher color temperature than a "warm white") is going to look brighter
due to the sensitivity of the eye to greens and blues in the higher
temperature color.
Cool white is also often referred to as "bright white" while warm white
is often referred to as "soft white". Grow bulbs and plant bulbs are
often in the middle and rich in the greens and blues. According to the
Philips tube jacket from my "Natural Sunlight" 4' FL plant bulbs, they
consider "Natural" (plant / grow) to be 5000K and "Daylight" to be 6500K
while they rate "soft white" to be 3000K. DON'T go by color names. Go
by color temperature (K / Kelvin), which is better defined as it's the
"black body radiation" color spectrum curve of a given temperature. The
cooler color temps (4000-5000K) seem to relate to slightly higher lumens
per watt, probably due to less need for color shape filtering to produce
the warmer white tones.
I'm now starting to look over the cost of replacement 4' tubes for the
4' FL fixtures. Looks like they're in the $30-$40 range per tube with
slightly lower lumens (but some of those lost lumens from the FL tubes
are IR and UV range). Most of the long-tube LED FL replacements are
chiming in at 80-100 lumens per watt at 18W - 23W per tube for a
4' (40W) FL replacement. We're getting there. We're getting there real
quick. "Shop light" FL tubes are typically 4000K-5000K color temp.
Living space, most people seem to like 2700K - 3000K warm whites like
the old incandescents and lamps of yore... I like my office at 5000K.
> Wife groused about the bedside lamp being too dim. I vacuumed the cat
> fur off the shade and got a noticeable difference. Seems the black
> cats have been polishing the shade on the inside :-)
Yeah there's always that. I always have to be careful, too, when
putting new bulbs in fixture sets because the older bulbs (particularly
CFLs) are going to look dimmer because they are dimmer as they age.
CFL's and FL's age and dim much faster than LEDs.
Just showed off something to June earlier today. When she got back
home, the kitchen can lights were off. I looked at her and said "and
this is the REAL REASON I like LED's" as I flipped the cluster on at low
dim. The CFL's in the 3 cans were this dim angry orange glow as they
struggled to warm up. The LED in the 4th can was immediately on the job
and bright at its low level. Cranked the dimmer up and the CFL's where
STILL struggling to catch up (but doing much better). In 5 minutes or
so (depending on dimmer setting) they'll catch up. But LED's will even
beat incandescents in coming up to full output and dimmer slope is very
smooth.
I'm going to work up a minimum inventory now of new "spare bulbs" that
are all LED and begin rotating them in. I still have some (too many)
PAR 30s CFLs for our smaller can lights and accent lights. Our outdoor
floods are all CFLs and that will be pricey to replace at current prices
but they're all relatively new and I can put them off a year or two as
well. As they get cheaper, they get cheaper, but I'm never in a rush to
run out and buy and I can rotate them into service as I need them. I
don't HAVE TO replace everything all in one rush. We've still got some
incandescent bulbs till burning bright. When they go, they go.
I feel we're now at the saddle point in the curve, the break-even point
where, even if it's more expensive up-front, the longer term return on
investment in LED's makes them more than worth while. If you can afford
to take the up front hit or can stretch it out while you rotate them in,
it's now worth the effort. Up till now, these have been "experiments"
for me. Now, I'm convinced and a believer. I've convinced myself that
this is the way to go.
My last challenge (and this is a killer) is that bloody 500W Quartz
Halogen Flood in the back. We're NOT there YET. Not residential, net
quite yet.
> On Aug 11, 2013 5:21 PM, "Ron Frazier (ALE)"
> <atllinuxenthinfo at techstarship.com> wrote:
> Hi Mike W and all,
>
> It's cool to see that you have found the new LED's to be
> acceptable. These recent developments are very encouraging.
> I think that, any time a CFL burns out, I may replace it with
> a LED, although I have a number of spare CFL's. I don't know
> much about directional lighting though and don't think I have
> any.
>
> Your comments prompted me to do some additional research.
>
> In the previous discussion, I was encouraged to look at these
> things in terms of lumens rather than incandescent wattage
> equivalent. This is very difficult, but obviously desirable.
> One reason it's difficult is that I have no sense of how many
> lumens light an area, but I do have a sense of how many watts
> do so. I guess this is just a matter of practice.
>
> I dug up these articles:
>
> http://en.wikipedia.org/wiki/LED_lamp
> http://en.wikipedia.org/wiki/Fluorescent_lamp
> http://en.wikipedia.org/wiki/Fluorescent_lamp_formats
> http://en.wikipedia.org/wiki/Incandescent_light_bulb
>
> These have lots of good info, although some of the info in one
> article is questioned. In general, I think wikipedia is a
> good source.
>
> The other reason that it's hard to think in lumens is that
> there is lots of marketing BS out there.
>
> To help, I made the following from a chart in the incandescent
> lamp article. This shows the lumen output of each type of
> each standard incandescent bulb. I don't know where they got
> the data, but the numbers seem reasonable. I've added a third
> column that computes the numbers for an acceptable 10%
> variance from the norm, when considering whether an LED light
> bulb is indeed equivalent to an incandescent bulb of X
> wattage.
>
> Incandescent Bulb Output Chart
>
> Power (W) ----- Output (lm) ----- Acceptable +/- 10%
> 5 ----- 25 ----- 23 - 28
> 15 ----- 110 ----- 99 - 121
> 25 ----- 200 ----- 180 - 220
> 40 ----- 500 ----- 450 - 550
> 60 ----- 850 ----- 765 - 935
> 75 ----- 1200 ----- 1080 - 1320
> 100 ----- 1700 ----- 1530 - 1870
> 150 ----- 2850 ----- 2565 - 3135
>
> So, if I'm buying a bulb that claims to be 60 W equivalent, it
> should be between 765 and 935 lumens. If it's outside this
> range, I'm going to avoid buying it and assume the
> manufacturer is trying to mislead the customer by making them
> think they're getting more light than they really will. I saw
> some 40 W equivalent candelabra bulbs that output 300 lumens.
> I would not buy those as I consider the labeling misleading.
>
> When I mentioned the possibility of replacing the 4' FL tubes
> we have, my wife said don't bother. The fixtures are ugly.
> Just replace the whole thing. I guess she's got a point. I
> think I'll defer that till later. New 4 - 6 bulb fixtures and
> 4 - 6 LED's would probably cost me $ 200 - $ 300.
>
> I need to find a place to recycle 4' FL tubes and 8-9" circle
> FL tubes.
>
> If the packaging on a bulb doesn't tell the color temperature
> (2700 K is soft white) and the lifespan in hours or something
> that's convertible to hours and doesn't say if it's dimmable,
> I'd probably avoid it. As others mentioned previously in the
> other thread, you might also have to consider if they're rated
> for enclosed use and if they are orientation sensitive.
>
> Hope this helps.
>
> Sincerely,
>
> Ron
>
>
> On 8/11/2013 1:52 PM, Michael H. Warfield wrote:
> Hey we all had a lively discussion a while back about
> lighting class
> LEDs. Just thought I would follow up and report my
> latest experience.
>
> Our kitchen was remodeled years ago with 4 recessed
> R40 can lights on a
> dimmer. We've used dimmable CFLs in them since and
> have gone through a
> number of them. So, yet another one burned out (they
> start to flicker
> badly before they completely die). Ran out to Home
> Depot and bought
> another matching 20W (85W equiv 900 lumen) CFL but
> also bought a close
> equivalent Philips R40 14.5W 800 lumen LED. I bought
> the CFL just in
> case the LED didn't match the other three lights
> closely enough for
> June's taste. :-)
>
> Numbers...
>
> CFL: $12
> 900 lumens
> 20W
> 7.3 years life expectancy (based on 3 hours per day).
>
> LED: $35
> 800 lumens
> 14.5W
> 22 years life expectancy (based on 3 hours per day).
>
> Both bulbs 2700 degree color temp.
> Both bulbs dimmable.
>
> Oh, my... Based on life expectancy (3 CFLs == 1 LED)
> they are almost
> identically priced with the LED slightly cheaper.
> You've just got that
> upfront cost but, then, it's 1/3 the number of bulbs
> to change and buy
> at the store...
>
> Now... Subjectively... That 800 lumen bulb matches
> up to the 900 lumen
> CFLs in the other 3 cans almost perfectly (color temp
> and brightness).
> Again, subjectively, it actually looks to be slightly
> brighter and the
> face of the bulb is uniformly clean and white and
> looks more pleasing to
> me than the encased tubes of the CFLs. The bulb is
> specifically
> designed for "down lighting" like these can lights
> (it's right on the
> packaging). June is delighted with it. I think I've
> bought my last
> CFL.
>
> So, to date, I've now replaced standard bulb shaped
> bulbs with LEDs and
> candelabra based bulbs in ceiling fans with LEDs and
> now dimmable CFLs
> in recessed can lights with LEDs. The only thing left
> around this joint
> now are the full sized 4' fluorescent bulbs.
>
> In my book, LEDs have arrived.
>
> Regards,
> Mike
>
>
>
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--
Michael H. Warfield (AI4NB) | (770) 985-6132 | mhw at WittsEnd.com
/\/\|=mhw=|\/\/ | (678) 463-0932 | http://www.wittsend.com/mhw/
NIC whois: MHW9 | An optimist believes we live in the best of all
PGP Key: 0x674627FF | possible worlds. A pessimist is sure of it!
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