Talk:Incandescent light bulb

Semi-protected edit request on 9 March 2020

actually, tomas edison didn't invent the lightbulb, he just inproved it. He bought the patent for it from two Canadian inventors, Mathew evans and henry woodward. 207.228.78.204 (talk) 23:06, 9 March 2020 (UTC)

 Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. DarthFlappy (talk) 23:12, 9 March 2020 (UTC)

Phoebus cartel limiting bulb lifespan

The article currently has the sentence:

Early bulbs had a life of up to 2500 hours, but in 1924 a cartel agreed to limit life to 1000 hours.<1>

The article that it cites claims that this was done to increase bulb sales and is an example of planned obsolescence. The idea is that light bulbs could go up to 2500 hours, and the cartel decreased that just to increase bulb sales to scam consumers. After looking into this, I'm fairly convinced this is a misconception that's been spread and has become a well known "did you know" style factoid. In 1951, Monopolies and Restrictive Practices Commission in the United Kingdom issued a report to Parliament and noted that:

"As regards life standards, before the Phoebus Agreement and to this day the general service filament lamp was and is designed to have, on average, a minimum life of 1,000 hours. It has often been alleged—though not in evidence to us—that the Phoebus organisation artificially made the life of a lamp short with the object of increasing the number of lamps sold. As we have explained in Chapter 9. there can be no absolutely right life for the many varying circumstances to be found among the consumers in any given country, so that any standard life must always represent a compromise between conflicting factors. B.S.I, has always adopted a single life standard for general service filament lamps, and the representatives of both B.S.I, and B.E.A., as well as most lamp manufacturers, have told us in evidence that they regard 1,000 hours as the best compromise possible at the present time, nor has an evidence been offered to us to the contrary. Accordingly we must dismiss as misconceived the allegation referred to above." Source

Harizotoh9 (talk) 11:41, 20 April 2020 (UTC)

The optimal life depends on the cost of light bulbs, the cost to change one, and the cost of power. For industrial use, where the cost to change is higher, longer life but a little less efficient, by designing for 130 volts and running them at 120 volts. A 60W bulb that lasts 1000 hours uses 60kWh in its life, costing about $7.80 at the US average of $0.13/kWh. Gah4 (talk) 12:56, 20 April 2020 (UTC)

Immediately after WW1, Japanese lamp manufacturers entered the American and British markets. British authorities set increasingly strict specifications for efficiency (watts/HK) and service life. As ETZ reported in 1921, a test procedure for service life that was deemed suitable had been proposed the previous year. Since then, this standard has also spread to mainland Europe. So, four years later, Phoebus has not invented anything new. --Virtualiter (talk) 15:19, 30 May 2024 (UTC)

Semi-protected edit request on 21 April 2020

Change "while-light source" to "white light source" in the sentence, "a while-light source with all visible wavelengths present has a lower efficacy, around 250 lumens per watt." Jreamm (talk) 09:24, 21 April 2020 (UTC)

Semi-protected edit request on 21 April 2020

Change "becasme" to "became" in the sentence, "Lamps used for several hundred hours becasme quite fragile." Jreamm (talk) 09:46, 21 April 2020 (UTC)

 Done – Thjarkur (talk) 11:31, 21 April 2020 (UTC)

glue in the cap - "Schellack"/shellac

i can only give as reference a link to the german wiki : "Als elektrischer Isolatorlack auf Wicklungen und als Kitt, der das Glühlampenglas mit dem Metallgewinde verbindet, ist er wegen der gleichen Wärmeausdehnung noch im Einsatz." see under "gegenwärtige Anwendungen" Schellack - wiki--Konfressor (talk) 08:27, 24 February 2021 (UTC)

Well, that's very likely so, but this is more relevant to copper wire or magnet wire, or even the shellac article than it really is for this one. That they use magnet wire to connect the electrode-stems, protruding from the bulb, to the threaded cap is no mystery. Magnet wire is ideal in most any situation where you need an extremely thin insulator with good dielectric breakdown resistance, and temperatures that may exceed the melting point of most plastics. It seems like a bit too much detail for this article, which is already over-sized. We're not an instruction manual on how to build them. Note that this does not refer to the seal between the glass and electrodes, which is done by welding to create a hermetic seal. Shellacs and glues emit volatile organic compounds (VOCs) that have a tendency to fill any vacuum, plus they burn up during the vacuuming process when the glass is heated to red-hot to purge any oxygen or water vapor clinging to the glass via adsorption. This only refers to the wires connecting the threaded cap. (Not to mention that Wikipedia is not a reliable source, so you'd need a better one.) Zaereth (talk) 08:59, 24 February 2021 (UTC)

Source for this dubious claim?

"Incandescent bulbs typically have short lifetimes compared with other types of lighting; around 1,000 hours for home light bulbs versus typically 10,000 hours for compact fluorescents and 20,000–30,000 hours for lighting LEDs."

Look, this is a straight up lie. Was this a test from a sterile lab or actual living apartments and homes? All those new high complexity expensive lamps usually die out far earlier than old primitive incandescents. It is so bad, that many people don't see value in changing into new so-called 'economical' one, because they costs far more (5-10 times more), but get broken after less than a year, while old ones work for several years without any problems. Of course, electricity wiring is a factor.

Presumably any test has to have some specified control conditions, though they may not be realistic for many real-world uses. Our articles do note that some of the more-modern technologies are more sensitive to environmental and other stresses than incansescents. Every bulb-package I've seen recently has an expected-lifetime on its package. LED lamp#Comparison to other lighting technologies seems multiply-cited. DMacks (talk) 10:26, 7 July 2021 (UTC)

It's pretty well sourced in the body of the article, although it does talk about a conspiracy to limit lifetime to 1000 hours beginning back in the early days. A conspiracy that, once discovered, was apparently outlawed. The source for that is the IEEE, which is a very reliable source in the field of lighting.

The problem with a lot of these numbers is that they are sales brochure-type numbers and are indeed based upon ideal conditions. For example, fluorescents can have drastically varying lifetimes depending on how they are used. Counterintuitively, fluorescents last the longest when they are left on all the time; it's switching them on and off that dramatically reduces their life. When they do wear, it's caused by sputter, which is impossible to predict reliably, because the tiniest difference at the time of manufacture can make huge differences in the rate of sputter. (See: Chaos theory.) Lifetime for fluorescents can vary dramatically between different manufacturers, between different batches from the same manufacturer, or even between lamps that come off the production line one after the other. The best you can get is a ballpark range.

With LEDs, the technology is still too new and still changing very rapidly. Lamps that have a pleasant spectrum are still fairly new, there is a total lack of standardization, and suppliers don't really want to stock them because by tomorrow they may be obsolete, and then they'll be stuck with them. In most cases, I believe they are likely basing their info on the lifetime of the LEDs themselves, whereas in my experience the limiting factor tends to be in the drive circuitry (possibly by design). Long life is rarely in the manufacturer's best interest, so it's up to the customer (supply and demand) to dictate what they are willing to settle for. Manufacturers often push consumers in the direction they want by making older technology crappier and crappier, until nobody buys them anymore (planned obsolescence). For example, nearly all the incandescents I find on the market anymore are vacuumed rather than gas filled, which shortens their life dramatically.

Unfortunately, we are stuck settling for the numbers provided to us by reliable sources, and with incandescents and fluorescents, we have the benefit of hindsight and a historical overview. Zaereth (talk) 18:35, 7 July 2021 (UTC)

GLS light bulbs

GLS light bulbs redirects here. Perhaps it should say what that means... (Also: I got here trying to find out what GLS means from a listing of an LED GLS bulb, so incandescent-only is probably wrong.) 86.26.33.25 (talk) 18:30, 14 January 2024 (UTC)

Fixed. GLS light bulb now redirects to Incandescent light bulb § Common shape codes, which now mentions "GLS".--Srleffler (talk) 20:02, 14 January 2024 (UTC)

Are incandescent lightbulbs bad during winter

If most of the energy from these bulbs are “lost” to heat.. isn’t it true that during winter months the heat emitted (from now banned and “illegal”) aids in the necessity to supplement heat in other forms? 136.34.207.21 (talk) 05:18, 20 January 2024 (UTC)

An electric resistance heater, particularly one up by the ceiling, isn't a very efficient heater, either. MrOllie (talk) 05:24, 20 January 2024 (UTC)

If your house is heated with electric resistance heaters, usually baseboard heaters, but sometimes central heating, it is probably close enough. Coal, oil, and nuclear plants are about 33% efficient in converting heat energy to electrical energy. So, resistance heating is about 33% as efficient as home gas our oil heat. Heat pumps, depending on outside temperature, heat the house with about 3 times the electrical power used. (They don't like to call them 300% efficient.) From primary energy (coal or oil into a power plant) to heat out of a heat pump, is about 100% efficient. Reminds me, many college dorms don't allow room heaters, but they do allow computers. Some years ago, people were buying old(er) computers, like desk side Sun systems, which warm up the room pretty well. Computers are also about 100% efficient in converting electrical power into heat. Gah4 (talk) 23:19, 20 January 2024 (UTC)

It is hard to make anything that is not 100% efficient at converting electrical energy into heat. Because of entropy all energy ends up as heat, eventually. As you noted, heat pumps are usually more than 100% efficient at heating a space with electricity and burning stuff where you want the heat is usually more efficient than burning it somewhere else to produce electricity, then using the electricity to produce heat.--Srleffler (talk) 23:27, 20 January 2024 (UTC)

Yes, in the winter months no energy is actually wasted. It all ends up as heat. While light bulbs are around 2% efficient as light sources, they are in the end 100% efficient as heaters. Even better, much of the waste from an incandescent bulb comes in the form of infrared radiation, so the bulb heats whatever the light hits. In the summer, these bulbs are much worse than you would think since not only is ~98% of the energy they consume wasted, if you have air conditioning the A/C system consumes extra energy to remove that waste heat from the building.

Over the course of a year, incandescent light bulbs are still a net loss compared to more efficient lighting sources. It's better to have your lighting system make light and your heating system make heat.--Srleffler (talk) 23:24, 20 January 2024 (UTC)

I have to agree with Srleffler. Electric resistance heaters are actually the most efficient heaters around. Of course, that doesn't include losses in the generation process or electrical grid, but even so they still tend to outperform all other types of heating.

Heat pumps, on the other hand, are a little more tricky. They're advertised as being up 300% efficient, even though that would violate the laws of thermodynamics. In reality, that's like describing the efficiency of a fuel tanker as both the motor efficiency plus the fuel energy it's moving. That 300% efficiency is not the actual conversion efficiency of the heat pump, but the conversion efficiency plus the added heat being pumped, which is different. The conversion efficiency of a heat pump is the ration of electrical input per the amount of heat generated by the compression process. When used for heating, this compression-heat is added to the heat being pumped, so it only seems like it violates the 2nd law. But for cooling the compression-heat becomes waste, so heat pumps are less efficient at cooling than heating.

With incandescent lamps, a lot depends on how many windows you have, because a lot of that visible and near-IR will go right off into space if it can find a way out (unlike most IR heaters). Still, I noticed a definite increase in my heating bill when I switched my lights to LED, but in cold climates like mine (Alaska), cooling is never an issue (most people don't even have A/C). And when the Sun is up 20 hours a day in the summer, there's no need for lights. Most people don't live in such a climate, and there are better ways to compensate, like getting an electric space-heater. Zaereth (talk) 21:41, 25 January 2024 (UTC)

CFLs

Moved from User talk:Kvng § CFLs

 – ~Kvng (talk) 14:49, 26 April 2026 (UTC)

Just curious about this edit. Compact fluorescent bulbs are pretty much obsolete where I live. Is that not the case where you are? One can still find them, but they are bottom-shelf items, below the rows of LED bulbs. Srleffler (talk) 06:34, 26 April 2026 (UTC)

@Srleffler, I don't think you can buy them anymore. There are still some in use and they are still in our memories though. ~Kvng (talk) 14:50, 26 April 2026 (UTC)

At some point they will not be important enough to mention in the introduction, even if they are covered in the body of the article. --Srleffler (talk) 17:48, 26 April 2026 (UTC)

If we can get this comparison in the body, I'm less concerned about keeping it in the lead. ~Kvng (talk) 18:03, 26 April 2026 (UTC)

For what it's worth, you can still buy them. It seems mostly replacement lamps for fixtures with ballasts in them, rather than screw-in incandescent replacements with a ballast in the base, but you can still buy those too. I don't know why anyone would, but you can. Ccrrccrr (talk) 02:03, 27 April 2026 (UTC)

Inclusion of a more detailed sentence RE ban

In the lead, the sentence which details the opposition to the banning of incandescent light bulbs only said, "These bans have been controversial in some cases." The section dedicated to the bans in the body is two paragraphs long with one of those paragraphs dedicated to the opposition. Per MOS:LEAD the lead must reflect and summarize the content in the body. I believe that the sentence above does not really tell the reader anything and does not even summarize the second paragraph to any meaningful degree. I added a new sentence which reads, "Opponents of incandescent light bulb bans cite concerns about alternative bulb costs, poor light quality and potential health risks from fluorescent and LED lighting, and general opposition to government regulation." Which I think more accurately reflects and summarizes that paragraph. Gjb0zWxOb (talk) 15:23, 20 May 2026 (UTC)

The fact that this obsolescent technology was banned in some places is not all that important in its history. As you noted, the whole topic only amounts to two paragraphs in a quite long article. It doesn't merit more than a sentence in the intro.

The paragraph on objections to the bans in the body of the article is probably undue coverage of a minority position. If you feel the intro is out of step with the coverage in the body, I would be happy to reduce the coverage in the body of the article.

The sentence you provided in the intro is definitely WP:UNDUE coverage: it spends more than twice as many words on the opposition to the bans as it does on the bans themselves. --Srleffler (talk) 04:03, 21 May 2026 (UTC)

I removed the passage in the body of the article about the 2008 opinion on health effects of compact fluorescent lighting. The cited document is pretty weak, and it is not very relevant to the general question of health effects of modern lighting systems, as compact fluorescent lighting is itself obsolescent and the health effects the document discusses are limited to people with health conditions that make them light-sensitive.--Srleffler (talk) 04:15, 21 May 2026 (UTC)