
Return of incandescent light bulbs as MIT makes them more efficient than LEDs - randomname2
http://www.telegraph.co.uk/science/2016/03/12/return-of-incandescent-light-bulbs-as-mit-makes-them-more-effici/
======
dkbrk
This news article doesn't even mention the article's name, the authors, or
when it was published.

It was actually published in January, and has just now been picked up by the
Telegraph.

Here is the citation:

    
    
        Ognjen Ilic, Peter Bermel, Gang Chen, John D. Joannopoulos, Ivan   
        Celanovic, Marin Soljačić. Tailoring high-temperature radiation and
        the resurrection of the incandescent source. Nature Nanotechnology,
        2016; DOI: 10.1038/nnano.2015.309                                  
    

And here is the actual paper, via Sci-Hub: [http://sci-
hub.cc/10.1038/nnano.2015.309](http://sci-hub.cc/10.1038/nnano.2015.309)

The Telegraph's explanation is terrible: "with a special crystal structure in
the glass they can bounce back the energy which is usually lost in heat, while
still allowing the light through."

The tungsten filament is sandwiched between two plates made up of layers of
oxides, designed to selectively reflect infrared radiation and transmit
visible light.

They used a numerical model to design and evaluate various candidate
compositions for these plates. For a proof-of-concept, they chose one which
uses layers of silicon oxide and tantalum oxide, with 90 layers in total per
plate. This reflected about 90% of infrared radiation, producing a luminous
efficiency of about 6.6%. This is comparable to commercial LEDs and compact
fluorescents, though far from state-of-the-art.

However, the results closely matched their numerical model, and a more complex
structure comprised of layers of silicon dioxide, aluminium oxide, tantalum
oxide and titanium dioxide, with 300 layers in total, should produce a
luminous efficiency of 40%. This is significantly better than the state-of-
the-art in LEDs (about 15-30%). They did not, however, actually build that
one.

I have no idea how expensive this would be to commercialise. It doesn't sound
like the physics is particularly complex, but manufacturing costs could be
prohibitive. I think it's safe to say we won't be seeing it outside the
laboratory any time soon.

~~~
collyw
"The Telegraph's explanation is terrible: "with a special crystal structure in
the glass they can bounce back the energy which is usually lost in heat, while
still allowing the light through."

The tungsten filament is sandwiched between two plates made up of layers of
oxides, designed to selectively reflect infrared radiation and transmit
visible light."

Whats terrible about that? Its the same as what you said using words that
could be understood by a child.

~~~
woodman
Ask the child to draw it, you'll notice the problem. One description makes me
think that the glass has some new treatment, the other makes me think that
there is a new structure within the bulb.

~~~
andrepd
Splitting hairs. The point, as succinctly as possible is that:

Incandescent bulbs are inefficient because they lose a lot of energy as heat
instead of light.

This counters that by introducing a crystal that selectively blocks the heat
and lets the light through.

Maybe the explanation is wrong in the minutiae but it gets the fundamental
point across.

~~~
thaumasiotes
I don't understand how that's supposed to make the bulb more efficient. If
you're trying to _keep the interior of the bulb hot_ , mission accomplished.
But the problem we're trying to solve is that when we run a current through
the filament, some of the energy we supply becomes visible light and some
becomes infrared light. We want more of it to become visible light and less of
it to become infrared light. How does preventing infrared light from leaving
the bulb help with that?

~~~
Someone
Here’s my take on this (corrections welcome): the thing you need to get light
out is a hot filament. You use electricity to a) make it hot and b) keep it
hot. Both are easier the better the filament is thermally isolated.

Caveat: if that argument is correct, I would think a bulb with triple glazing
would help, too. Has that been tried?

~~~
mapt
The thermal mirror needs to selectively reflect infrared while being
transparent to visible light, and it needs to bounce radiation back and forth,
which requires a certain geometry. The novelty of this paper is creating a big
flat filament sandwiched between high-temperature plates that reflect infrared
and can be deposited as layered coatings.

------
degenerate
People complaining about LEDs being too "bright" or "clinical/sterile" were
too bothered to look into the different color temperature options. The
annoyingly bright bulbs are around 5000K brightness which would make a home at
night feel like a fully-lit classroom. I have 2700K bulbs which give off a
much cozier incandescent glow: [http://blog.batteriesplus.com/2013/seeing-
things-in-a-differ...](http://blog.batteriesplus.com/2013/seeing-things-in-a-
different-light)

Sure, the bulbs take about 1/5 of a second to turn on, which is not instant,
but the cheaper LEDs can take up to 2 seconds to reach full brightness. You
have to buy a better made bulb to get the quicker "on", which means spending
more money. People only trying the cheapest LEDs available are the ones
complaining the most about them, I'd assume.

~~~
strictnein
Yep. I've replaced about a lot of the bulbs in my house with LEDs. The key is
to buy a number of them, find ones that you like, and then put the ones you
don't like in places that the color doesn't matter as much (garage, storage
areas, etc).

For me, a lot of the Philips LED Soft White (2700k) bulbs worked.

~~~
tzs
I've found that that Walmart "Great Value" brand 8.5 W, 800 lumen, 2700K,
20000 hour bulbs are nearly indistinguishable from the 60 W incandescent bulbs
I had before, except that these LEDs are not dimmable.

They are nominally about $2 each, although they frequently drop the price to
an astounding $0.17 each. I'm not sure if these price drops are due to some
sort of automatic at-the-register rebate from the local power company, or just
an internal Walmart effort to promote efficient lighting.

~~~
cowkingdeluxe
The same company that manufacturers these for Walmart is called TCP and they
sell the bulbs on Amazon as well. I've bought about 30 of them.

Pretty happy with them so far. The only problem I have had (as with all brands
so far) is led bulbs seem to interfere with my garage door receiver signal (if
placed right next to it).

------
nostromo
We switched to LEDs about two years ago and have switched back to halogen
bulbs recently for few reasons.

1) It didn't actually make much difference on our electricity bill. I believe
this is because we use most of our lighting during the winter, and the wasted
heat from the traditional bulbs isn't really wasted at all -- we just shifted
more work to our electric heating system.

2) Many of the bulbs had burnt out. I am now very skeptical of all the "20
year lifetime" claims since we lost many expensive bulbs in two years.

3) The light quality just isn't great. People will argue this point, and I
can't point to any evidence to support my claim, but our perception was that
the light was either too blue, or too yellow, and just "looked weird." I
wonder if it's related to the strobing of the LEDs.

LED slow motion:
[https://www.youtube.com/watch?v=zAfWKcg8Bq0](https://www.youtube.com/watch?v=zAfWKcg8Bq0)

Halogen slow motion:
[https://www.youtube.com/watch?v=sCD5BMr6LsA](https://www.youtube.com/watch?v=sCD5BMr6LsA)

~~~
djsumdog
I have to agree. Every few years I'll try again with LEDs and energy efficient
bulbs. I'll look online, buy a few different brands and specifically look for
the ones with a "cool" colour temperature that should look natural.

In every instance the lighting was terrible. I really haven't yet found an
energy efficient bulb that didn't make my place look like a jail cell.

My current place has halogen track lighting and I really like it.

~~~
lutorm
You don't want "natural" lighting if you want it to look like an incandescent.
"Natural", ie "day" light is very blue. You specifically want a _non_
-natural, warm color temperature.

~~~
wlesieutre
Fire is plenty natural.

In architectural lighting, the reference spectrum depends on color
temperature. Warm whites are measured against the black body spectrum, cool
whites are measured against the daylight spectrum.

~~~
lutorm
What do you mean? Daylight is very close to a blackbody.

~~~
wlesieutre
Close but not quite, atmospheric effects block some portions. We use the CIE
d-series illuminants as an approximation:
[https://en.m.wikipedia.org/wiki/Standard_illuminant#Illumina...](https://en.m.wikipedia.org/wiki/Standard_illuminant#Illuminant_series_D)

That's done because it's very unusual to get a black body radiator that hot on
Earth, so if you're talking about something on the cool white end odds are
high it's daylight or trying to approximate it, not a tungsten filament or a
campfire.

------
colanderman
> Traditional incandescent bulbs have a ‘colour rendering index’ rating of
> 100, because they match the hue of objects seen in natural daylight.

> Previously researchers have warned that the blue light emitted by modern
> bulbs could be stopping people from getting to sleep at night

These two sentences do not go together. Daylight contains LOTS of blue light.

5 seconds of research into CRI says that the first sentence is false. CRI
compares a light source to an _ideal black body_ , not necessarily daylight.

~~~
LgWoodenBadger
Most photographers understand the color temperature differences between
incandescent/tungsten light and daylight, and have to account for them by
setting their camera's white-balance (manually, or automatically).

So it comes as a shock to me that a traditional incandescent bulb's coloring
matches that of natural daylight.

[http://lowel.tiffen.com/edu/color_temperature_and_rendering_...](http://lowel.tiffen.com/edu/color_temperature_and_rendering_demystified.html)

~~~
tigeba
I think this is a difficult concept for people because our brains do such a
good job compensating for mixed lighting. Our built in auto-white balance is
too good. One example I use to explain this is the classic Hollywood
'moonlight' trick, which is achieved by using a daylight balanced source like
a large HMI, and then using film or a camera that is balanced for tungsten.
Looks like daytime to the eye, but on camera it looks like moonlight.

There are even special gels just for correcting various light sources CTO
(color temp orange) CTB (color temp blue) and minus green (correct gross flo
lights). The rest are usually regarded as 'party colors' since they are for
non-technical corrections.

------
jandrese
This article read an awful lot like a marketing puff piece and failed to
answer some obvious questions. There is way too much "those evil fluorescent
bulbs are making your life miserable" in the article.

1\. How long are the bulbs going to last? 2\. How expensive would they be to
manufacture? 3\. When could we see these in stores?

Often times there is a long road from laboratory prototype to production, and
the supposed cost savings in electricity won't matter if they only last 1,000
hours and cost $100/bulb.

~~~
ams6110
Anecdote time. Those evil flourescent bulbs have made my life miserable.

They don't last substantially longer in the real world. I am routinely
replacing them within 12 months.

They cost an order of magnitude more.

They are considered toxic waste with special clean-up and disposal
considerations.

The amount of energy they save as a fraction of my total electric bill is
inconsequential.

~~~
ars
> They don't last substantially longer in the real world.

Yes they do, I have a lot of them and I write the installation date on the
bulb - they have failed more or less inline with what the package said.

> They cost an order of magnitude more.

They cost $1. There is no reason they need to cost more than that.

> They are considered toxic waste with special clean-up and disposal
> considerations.

That isn't true, it's one of those urban myths that spread by email.

> The amount of energy they save as a fraction of my total electric bill is
> inconsequential.

What are you spending so much on electricity on?

~~~
MOARDONGZPLZ
>> They are considered toxic waste with special clean-up and disposal
considerations.

>That isn't true, it's one of those urban myths that spread by email.

It can be hazardous waste, you can't categorically say that it isn't true.
Both of you are technically wrong. While it's correct that low mercury bulbs
can be disposed of in dumpsters according to EPA, some states have stricter
rules with respect to even low mercury bulbs. I believe CA, WA, and VT all
require specific recycling of low mercury bulbs, for example.

Beyond that, looking at bulbs that are NOT low mercury, those DO become
regulated hazardous waste after they burn out according to federal laws. So
those MUST be recycled properly to comply with federal and state laws.

In any case, 100% of fluorescent bulbs contain mercury, which is really bad
for the environment. So even if you're legally allowed to throw them in
dumpsters, it's really not something you should be doing if you care about the
environment or the people in it.

Bottom line: Depending on the bulb and jurisdiction, a spent/broken bulb might
be classified as hazardous waste legally requiring special cleanup
considerations, or it might legally be able to be thrown in a dumpster. But
regardless of the law you should properly recycle 100% of bulbs because they
contain mercury (even if in small amounts).

~~~
ZenoArrow
Well explained, thank you for that.

This is off topic but, would you mind changing your username? I get that it's
mostly harmless but it's against the usual HN guidelines.

~~~
MOARDONGZPLZ
Dongz is a surname, fyi.

------
slowmovintarget
This article also doesn't mention the current U.S. law which says it is now
illegal to sell incandescent bulbs across state lines. The law should have
been written to mandate efficiency, not implementation. Now there must be a
legal fight to allow incandescent bulbs again (for the U.S., at least).

~~~
dalke
Why should a UK newspaper cover domestic US laws?

And in the US, the law described at
[https://en.wikipedia.org/wiki/Energy_Independence_and_Securi...](https://en.wikipedia.org/wiki/Energy_Independence_and_Security_Act_of_2007#B._Lighting_Energy_Efficiency)
suggests that the ban is not on technology choice but on efficiency, such that
a more efficient incandescent bulb would be fine.

~~~
slowmovintarget
From the legislation:

    
    
      (C) Candelabra incandescent lamps and intermediate 
                    base incandescent lamps.--
                              ``(i) Candelabra base incandescent lamps.--A 
                          candelabra base incandescent lamp shall not exceed 
                          60 rated watts.
                              ``(ii) Intermediate base incandescent lamps.--
                          An intermediate base incandescent lamp shall not 
                          exceed 40 rated watts.
    

Anything over 60 watts was to become unavailable by 2012, with a schedule to
retire the 40 and 60 watt bulbs. Ironically, this meant that to get the same
lighting levels, you were permitted to buy more 40w bulbs, but not a single
100w bulb.

As to the "why cover US law?" question, I thought it relevant because the
discovery was made by a US team at MIT and for there to be a "return" of
incandescent bulbs would require both US and UK/European markets to be opened
back up. Even if only as an irony juxtaposed with the location of the
discovery, it was related.

Now the law as stated would seemingly permit incandescent bulbs of equivalent
brightness to old 100w bulbs, but only if they are 27w or less. Or, you know,
you could just buy a gaggle of 27 watt bulbs.

~~~
dalke
What is your point about a candelabra incandescent lamp?

That concerns only lamps which use a "candelabra screw base as described in
ANSI C81.61–2006, Specifications for Electric Bases, common designations E11
and E12." Moreover, that is from a section which specifically allows them to
be incandescent, so long as they don't exceed a given power limit.

You also seem to have missed the part where it says:

> The rulemaking— (I) shall not be limited to incandescent lamp technologies;
> and (II) shall include consideration of a minimum efficacy standard of 45
> lumens per watt.

or the "Backstop requirement":

> If the Secretary fails to complete a rulemaking in accordance with clauses
> (i) through (iv) or if the final rule does not produce savings that are
> greater than or equal to the savings from a minimum efficacy standard of 45
> lumens per watt, effective beginning January 1, 2020, the Secretary shall
> prohibit the sale of any general service lamp that emits less than 300
> percent of the average lumens per watt emitted by a 100-watt incandescent
> general service lamp that is commercially available on the date of enactment
> of this clause.

This allows incandescent bulbs so long as they are significantly more
efficient than those sold before 2007.

As to why UK newspapers writers are supposed to understand the details of
domestic US law, and why UK newspaper readers are supposed to care, in order
to get an extra moment of irony - well, that seems like a lot of work for very
little gain. Especially when the EU has very similar laws, so UK readers may
default to think that the US is already in the same boat, so there's little to
no irony available.

------
Animats
From the paper: _" This experimental device is a proof-of-concept, at the low
end of performance that could be ultimately achieved by this approach."_

Somebody really needs to get MIT's PR department under control. The hype level
is so high it's embarrassing to a good school. Especially in materials science
articles. It's like reading the National Enquirer of science.

~~~
Faaak
Publish or Perish… Publish at all costs without going the extra mile.. A pity.

------
kazinator
> _The clinical white beam of LEDs and frustrating time-delay of ‘green’
> lighting has left many hankering after the instant, bright warm glow of
> traditional filament bulbs._

Sheer garbage. LEDs come on instantly, and are available in various color
temperatures, thanks to filtering: you can have then in 2700K. If your LED
isn't coming on instantly, it has some problem with the power supply, probably
because you bought the lowest bargain-bin crap you could get your hands on.

I've had Phillips flood lights (3000K) in my kitchen and living room for
several years. They come on instantly and put out a warmly colored light that
is consistent from the center of the spot to the fringes.

~~~
tacos
And your apples and oranges are the wrong color because the color rendition on
them is so poor that Philips doesn't even publish the number. The only
downlight I could find on their site has a CRI of 80 -- basically garbage. CRI
is imperfect but things glow green until you get to the low 90s.

------
brandon272
I built a house a couple years ago where the lighting used is predominately
LED bulbs and I absolutely hate it. The pre-determined lighting plan for the
home was presumably based on the brightness given off by certain incandescent
bulbs and placing LED bulbs in those locations that are supposed to be wattage
equivalent has resulted in a fairly dark house with what I would consider to
be low quality of light. Many of the bulbs used in certain fixtures also emit
a noticeable high pitched noise when on.

~~~
stephen_g
Sounds like pretty rubbish bulbs. Have you not tried replacing even one with a
good quality brand?

Of course, it might also just be that the lighting design wasn't very good in
the first place...

~~~
brandon272
I have no idea what a good quality brand is. And if I did find better bulbs it
would cost a fortune to replace all of the bulbs I just bought two years ago.

~~~
CamperBob2
Sounds like somebody spent a lot of money without doing any research.

I must have tried samples of a half-dozen different brands before buying
enough LED bulbs to retrofit all of my ceiling cans. Actually I sort of wasted
my time, because the (subsidized) $2.99 65w replacements from the hardware
store on the corner proved to be as good as any of them. No failures a year
later (N = about 36) so they seem to be working out OK.

~~~
stephen_g
Similar story here, I found my favourite LED bulbs at the supermarket!

------
jrapdx3
Didn't see it mentioned in other comments, but a particular failing of LED
lamps is their unsuitability for critical color matching applications.
Fluorescents and CFLs are available for that use, but to date haven't seen
LEDs that are satisfactory.

This is important in art studios, museums and other venues. For many years
I've used specialized 48" T12 fluorescents with good results.
Incandescent/halogen lamps are also essential because color selection can
depend on the target environment, there's a world of difference between indoor
illumination and daylight in this respect.

The high-efficiency lamps described in the article will likely be very useful
and a welcome refresh of a light source that's so far been hard to emulate
with LEDs.

With IR energy being pumped back into the filament, maybe it's an option to
run a hotter filament emitting a higher color temperature. More likely the
input energy is just decreased so the resulting filament temp remains in
conventional range. There still might be an issue re: time to filament burnout
not differing from conventional lamps unless the filament is modified in some
way.

In the long run I imagine LEDs will be improved, curbing the disproportionate
blue output, while enhancing and smoothing the long end of the spectrum. LED
dominance will probably be complete when color rendering is optimized, they
work properly with electronic dimmer switches, and lamp envelopes produce
illumination as diffuse as classic sources, e.g., like "frosted"
incandescents.

------
tsomctl
So, if I understand dkbrk correctly, this is a glass that transmits light but
reflects infrared. This seems to have a huge number of other applications
(assuming it is practical). Make windows out of it, so that your house stays
cooler in the summer and warmer in the winter. Keep your car cooler in the
summer. Better face shields for fire fighters. Put a window in your
refrigerator. Let people get closer to metal foundries/casting metal.

------
protomyth
So, if this works and is 40% efficient compared to LED or florescent bulb's
manage ~14% efficiency, do we ban all LED purchases in the US?

~~~
3JPLW
It is interesting to think about how this commercial product might have to
fight the anti-incandescent laws. Would this bulb be illegal in many
states/countries right now?

~~~
Brakenshire
In the EU, there are no incandescent laws, there are only limits on
efficiency.

------
GigabyteCoin
>Researchers at MIT have shown that by surrounding the filament with a special
crystal structure in the glass they can bounce back the energy which is
usually lost in heat, while still allowing the light through.

Why can't/don't they use those same crystals on LED lights?

~~~
fanf2
The crystals reflect back heat in order to improve efficiency by keeping the
filament hot. LEDs don't work by being hot.

~~~
GigabyteCoin
They do lose energy in the form of heat, though.

Ever seen the massive heatsinks required for a high wattage LED to work?

------
kup0
This was posted a while back and picked apart by the comments, as it has been
here too. This is all just "potential" improvements, just like we've been
hearing about "crazy new battery technologies" for the past few years and have
seen next-to-nothing come of it. Always good to see new tech and ideas, but
let's not kid ourselves into thinking this will make it's way back into homes
anytime soon.

"Return of incandescent light bulbs" is an incredibly misleading headline that
implies that due to this new tech, we're already starting to use these great
new efficient bulbs- um, no.

Not to mention, the prototype/initial version is nowhere near the "potential"
level of efficiency they are claiming.

------
pcunite
Here is an interesting thread about color quality (something rarely brought up
when LED gets mentioned).

[http://www.dpreview.com/forums/thread/3757505](http://www.dpreview.com/forums/thread/3757505)

------
nkozyra
> The clinical white beam of LEDs and frustrating time-delay of ‘green’
> lighting

I hear a lot about the "delays" in incandescent alternatives, but all of mine
are barely perceptible. My Flux bulb has like 400ms; it's palpable but how
could it ever annoy me? How often were you trying to illuminate something with
a light bulb within 400ms and missed it?

And of course, many of the adjustable/smart LEDs can mimic incandescent light
temperature with ease. They cost more, but not necessarily over their
lifetime.

As mentioned, this article was fluff.

~~~
thescriptkiddie
"Green" and "energy saving" are often used to refer to florescent lighting in
the UK. Florescent bulbs take some time to warm up before they reach full
brightness, which is what they are complaining about. LED bulbs like your Flux
don't have a delay.

~~~
ars
> Florescent bulbs take some time to warm up before they reach full brightness

They've had instant on fluorescent bulbs for a decade now, and they don't cost
more. If yours are slow switch to a different supplier.

~~~
jrockway
Instant start is not what the comment you're replying refers to. Instant start
is about how an arc is struck to get the gas to glow initially. The comment
above is referring to how the light gets brighter as it runs longer, well
after the gas begins to fluoresce.

[https://en.wikipedia.org/wiki/Fluorescent_lamp#Instant_start](https://en.wikipedia.org/wiki/Fluorescent_lamp#Instant_start)

~~~
ars
I know, I was not referring to instant start either. (I said instant on, so I
can see how that might be confusing.)

The CFL's in my house are full brightness immediately. I suppose a lab could
measure a change in brightness, but it's nothing that is visible to the eye.

~~~
thescriptkiddie
Zero-warmup florescent fixtures do exist, but I've never seen them installed
in a home. They work by continuously running a small current through the
filaments to keep the bulbs warm, which requires a separate always-on power
feed in addition to switched power. Normal (instant-start) florescents start
producing light instantly, and in sufficiently hot weather don't need to warm
up, but if it's below freezing expect less than half of rated brightness for
the first five or ten minutes. It's worse for CFL bulbs than for straight
tubes, and worse still for CFL bulbs installed upside-down because the mercury
settles.

~~~
kazinator
So it's like the "stand by" mode of a tube amplifier, which keeps the
filaments on.

Even though fluorescent lamps are called cold cathodes, "[a] cold cathode does
not necessarily operate at a low temperature: it is often heated to its
operating temperature by other methods, such as the current passing from the
cathode into the gas." (Wikipedia, Cold Cathode).

Obviously, the tech you're referring to requires a special circuit, since an
ordinary light socket goes comletely open circuit when switched off. (I.e.
anyone who claims to have these zero-warmup CFL's in ordinary light fixtures
is confused.)

I find that the slow warm-up time of regular CFL's is excellent for bathrooms.
When you have to "go" at wee hours in the morning, you don't want the full
glare in your sleepy eyes.

Your notes about the ambient temperature effect on warm-up time are spot on.
People who are not seeing the effect with CFL's may be living in a warm
climate or well heated home.

------
Fej
What are the chances of seeing this at retail in the next decade?

------
ourmandave
Thank goodness! My LED Easy Bake Oven takes _forever_.

------
ck2
Philips has already had car headlight bulbs that do this "radiate heat back as
light" trick.

They are VERY VERY bright. In fact the brightest headlights before you go to
real xeon. But they are not much more power efficient.

9011 HIR and 9012 HIR models

[http://store.candlepower.com/hirlighting.html](http://store.candlepower.com/hirlighting.html)

------
jrockway
Am I the only person that doesn't like "warm" light? I wish I could have all
the lights in my apartment be D65 like my monitor. It makes everything look
like a calm, cloudy day. At least with my monitor calibrated to that
temperature, anyway.

~~~
cels
They should rename "warm" to "nasty dingy yellow".

------
sdx23
"However even ‘warm’ finish LED or florescent bulbs can only manage an index
rating of 80 and most are far less."

This is simply not true. Current state of the art is >80\. If you search a
little you'll find LEDs with CRI 95.

------
Egidius
I'm suprised noone brought this documentary up:
[https://www.youtube.com/watch?v=-1j0XDGIsUg](https://www.youtube.com/watch?v=-1j0XDGIsUg)

------
NicoJuicy
The most interesting thing I ever read about light bulbs is that they used to
last 100 years. But manufacturerers limited this due to sales :
[http://spectrum.ieee.org/geek-life/history/the-great-
lightbu...](http://spectrum.ieee.org/geek-life/history/the-great-lightbulb-
conspiracy)

There is still one active for over 114 years and it has a 'live' feed
[http://www.centennialbulb.org/photos.htm](http://www.centennialbulb.org/photos.htm)
( 1 million hours and it's not that efficient anymore )

------
known
[https://en.wikipedia.org/wiki/Lumen_%28unit%29](https://en.wikipedia.org/wiki/Lumen_%28unit%29)

------
callesgg
When you live in a cold climate some light-bulbs become more efficient due to
the fact that the heat is not waste heat.

As it helps to heat up the room they are in.

~~~
imaginenore
Heating your home with electricity is probably the most expensive and the most
wasteful way.

~~~
mnw21cam
Depends. If your electricity comes from coal/gas fired power stations, yes it
is wasteful - just burn the fossils locally instead. If it comes from
hydroelectricity, solar, nuclear, or wind, then no it is sensible.

------
kefka
Grrr!

Incandescent lights, when heating would be used, are 100% efficient.

They provide 3% light output, and 97% heat output. A single one on provides a
great amount of heat and can easily provide spot-heat where humans are.

Instead there's CFLs and LEDs. And CFLs are a great way to spread mercury
pollution across a great area. Snopes has a decent article about hazards and
response:
[http://www.snopes.com/medical/toxins/cfl.asp](http://www.snopes.com/medical/toxins/cfl.asp)

~~~
mikeash
The electricity for my lights comes from thermal power plants with maybe 40%
efficiency and then loses a little bit more in transmission. If I use LED
bulbs, then that heat is replaced by my natural gas furnace, which is
somewhere around 90% efficient. Net result, even in the dead of winter it
saves energy to use more efficient bulbs. In summer, when I'm using
electricity to cool my house, the difference is even greater.

Resistive heating with electricity is just terribly inefficient. If you have
to do it anyway (because you need to run equipment, and that equipment is
already as efficient as it'll reasonably get) then you can benefit a little by
ensuring that this heat is put somewhere it's wanted. But if you don't have to
do it, don't do it.

CFLs suck, but LEDs are great. I fear that the CFL interregnum may have hurt
the cause of efficient lighting in general.

~~~
ars
> CFLs suck, but LEDs are great.

I have both. There's basically no difference, except the LEDs are hot on the
base and CFL's are hot on the bulb.

Power consumption is identical, CRI identical, and Cost per Hour (before
failing) is basically identical (assuming the hours listed on the package is
the truth).

> I fear that the CFL interregnum may have hurt the cause of efficient
> lighting in general.

It has not. I've been using CFLs for about 20 years (almost since the day they
came out), and they work just fine.

~~~
mikeash
CFLs take longer to come on, don't reach full brightness immediately, are less
efficient, don't last as long, and contain mercury.

I don't know what your personal statement about using CFLs for 20 years has to
do with my fear about the cause of efficient lighting being hurt. Your own
preferences don't necessarily reflect those of people in general.

~~~
ars
> CFLs take longer to come on

I have both. That isn't true. I have some LEDs that take longer, some CFL's
that take longer, and some (of both) that are effectively instant.

> don't reach full brightness immediately

Also not true. It used to be that way, and perhaps some poorly designed ones.
But there is no reason to buy any that are not instant.

> are less efficient

Again, not true - make sure to compare bulbs with equivalent CRI.

> don't last as long, and contain mercury.

This is true, and irrelevant. Also, LEDs cost more, and I'm not (yet)
convinced the hour ratings are actually accurate.

> I don't know what your personal statement about using CFLs for 20 years has
> to do with my fear about the cause of efficient lighting being hurt.

Your fear is unwarranted. CFLs work perfectly fine, and I know that because
I've been using them for a long time.

~~~
mikeash
I don't know what to say, besides that your statements run contrary to my
experience where they conflict, and I don't understand why you think it's
irrelevant that CFLs die quicker and are more poisonous.

A whole lot of people experienced CFLs and came away with the conclusion that
they suck. I fear that they will assume LEDs also suck.

~~~
ars
> I don't know what to say, besides that your statements run contrary to my
> experience where they conflict

Did you buy CFLs recently or only more than 10 years ago? What brand? I've had
excellent results with GE and GreatValue. Mixed results with Feit.

> and I don't understand why you think it's irrelevant that CFLs die quicker

Because I don't (yet) trust LEDs to live as long as they say. So that
advantage doesn't exist as far as I'm concerned.

> and are more poisonous

Because it makes no difference in actual use. You can toss them in the trash
if you want, or take them to Lowes/Homedepot to recycle. The amount of mercury
is too small to hurt anyone if they break.

------
bwilliams18
This will find enormous success in the theatrical market. Nobody is willing to
give up the CRI of tungsten filament fixtures.

------
ris
I love the first paragraph's insertion of a little EU-paranoia in the run up
to the referendum. Vintage Telegraph.

------
hackney
Add a solar panel and one of those newfangled forever batteries and I'm sold.

------
ricksplat
Is there anything to be said for their durability and versatility though?

------
nikolay
So happy as they are the healthiest night lighting anyway.

------
supergirl
I know the article is fluff when I see MIT in the title

------
bronz
wow. that is so fantastic. i wonder how they came to the 40% figure.

------
gaius
Good - no more toxic chemicals from so-called eco-friendly bulbs in our homes.

------
gherkin0
It's ironic that the factories that make incandescent bulbs are being shut
down.

