Bullshit units of measure - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: October 12, 2022, 11:20:00 pm
content: This is a new one... I'm shopping around for a new vacuum cleaner and Dyson boast on their website that their particular vacuums havex-number of "Air Watts" (even abbreviating it to AW). In the fine print it says "Suction tested to IEC62885-4 CL5.8 and CL5.9, tested at the flexible inlet, loaded to bin full, in Boost mode by independent third-party, SGS-IBR Laboratories US in 2022".This smells of PMPO and other "made up" units of measure.Edit: I stand corrected, it seems that there is some merit and standardisation to it. Looking at Wikipedia, the Air Watts article was created in 2008, so it seems it's not a new thing.

author: jpanhalt
author_rank: Super Contributor
timestamp: October 12, 2022, 11:33:02 pm
content: Output of air compressors can be related to watts (https://www.vmacair.com/blog/how-to-calculate-air-compressor-cfm-to-kw/). That's helpful in evaluating some wild claims of output from consumer units. I wasn't aware of the same type of conversion for household vacuum cleaners.If done rationally and by third parties, I see no problem with it, particularly if other manufacturers follow suit. It is, of course only one metric in a vacuum cleaner. I have a Dyson bought 20 years ago. It's OK, but there was a lot about my old Hoover that I liked better.

author: james_s
author_rank: Super Contributor
timestamp: October 12, 2022, 11:52:28 pm
content: It does annoy me, but the problem is there is no standardized unit accepted for measuring the performance of a vacuum cleaner. Power consumption is an easy one, but that obviously doesn't tell the whole story, it's easy to consume a lot of power producing mostly noise. I think actually air watts could make sense if it was made standardized. Connect a standardized air suction powered generator to the vacuum cleaner and record the power it is able to produce. Even that isn't necessarily a great measure of cleaning performance but it's a good start.

author: bdunham7
author_rank: Super Contributor
timestamp: October 12, 2022, 11:58:02 pm
content: If the airwattage is not some huge inflated number determined using some bogus method (like the ridiculous peak power rating) and it is applied uniformly, then I think it is great. That does appear to be the case, airwatts are less than electrical watts by some margin.https://en.wikipedia.org/wiki/Airwatt

author: MikeK
author_rank: Super Contributor
timestamp: October 13, 2022, 01:58:46 am
content: I think the bullshit unit of measure is the bucket, no?

author: Bud
author_rank: Super Contributor
timestamp: October 13, 2022, 04:00:06 am
content: To me it is Stone. Wikipedia seems to give all sort of figures what one Stone may equal to.

author: ejeffrey
author_rank: Super Contributor
timestamp: October 13, 2022, 04:15:38 am
content: Quote from: Halcyon on October 12, 2022, 11:20:00 pmAir watts is supposed to be closer to a real unit of useful work. Here in the US, you often see wet dry vacuums rated for something absurd like "6.5 peak HP" -- on a 120 V / 15 amp power outlet... Right... They get this by measuring the peak inrush surge current and multiplying by 120 V then dividing by 745 W/hp. This obviously has nothing to do with anything important and actually encourages manufacturers to not limit inrush current to get a higher HP rating.Take a look at this:https://www.homedepot.com/p/RIDGID-16-Gallon-6-5-Peak-HP-NXT-Wet-Dry-Shop-Vacuum-with-Detachable-Blower-Filter-Locking-Hose-and-Accessories-HD1600/304795082Air watts should be something more like deltaP * deltaV at the flow rate where that is maximized. In other words, mechanical work. You would normally rate mechanical work in horsepower, but since that was already taken by scam artists we get air watts. I'm sure there are ways to game the system but it is less bad than the BS horsepower ratings that it is trying to replace.

author: jonpaul
author_rank: Super Contributor
timestamp: October 13, 2022, 04:56:48 am
content: The D---n are ..overdesigned overpriced junk made in Chinaget a vintage hooverj

author: wraper
author_rank: Unknown
timestamp: October 13, 2022, 05:10:52 am
content: Quote from: jonpaul on October 13, 2022, 04:56:48 amNone of Dyson products are made in China AFAIK. Overpriced yes, but at least some of their products are very good. For example their hand driers are by far the best compared to anything else I've used. Hair driers are very good too, yes you can get something cheaper with similar performance, but it will be way bulkier and with way more annoying noise. There are a ton of crappy counterfeits on Amazon, ebay and other places though, so people often claim it's garbage. If you read something like magnetic attachments do not hold well, it's 100% counterfeit.

author: Berni
author_rank: Super Contributor
timestamp: October 13, 2022, 05:21:46 am
content: According to the definition on Wikipedia it sounds like a pretty reasonable measure of performance. It is basically a dyno for moving air. But yes if i sen this written on a box i would think it is bullshit marketing numbers.Tho units people are not familiar with are often manipulated by the no name brands. If you go looking for a flashlight online you will find plenty of handheld flashlights with claims like 5000 lumen 10 000 lumen sometimes even 100 000 lumen... yet the thing runs from 2xAA cells. Since people have no idea how bright a lumen is they beleve the numbers... even tho it would take multiple kW worth of LEDs to actually get such lumens.

author: james_s
author_rank: Super Contributor
timestamp: October 13, 2022, 07:16:13 am
content: Quote from: jonpaul on October 13, 2022, 04:56:48 amI've had a lot of different vacuums ranging from 1960s to modern and the Dyson I currently have is by far the best performing of any I've ever used. They're typically overpriced but I got mine on sale, I've had it for over a decade now and it's still going strong. I'd buy another one if I ever lost it.

author: james_s
author_rank: Super Contributor
timestamp: October 13, 2022, 07:20:30 am
content: Quote from: Berni on October 13, 2022, 05:21:46 amMany of the flashlights are greatly exagerated, however it would not take multiple kW of LEDs to reach those numbers. A 1kW metal halide lamp of the sort used to illuminate parking lots and sports fields is about 125,000 lumens. Recently these are getting replaced by LED lights that consume about 1/3 that.

author: thm_w
author_rank: Super Contributor
timestamp: October 13, 2022, 11:19:06 pm
content: Yeah Dyson is not junk, not even close, its just expensive. Anyone who says that has never owned or taken apart a Dyson product.Top performing cordless vac:

author: TimFox
author_rank: Super Contributor
timestamp: October 13, 2022, 11:41:43 pm
content: Quote from: MikeK on October 13, 2022, 01:58:46 amThe "barrel" is an multiply-defined unit, depending on what product is contained therein.seehttps://en.wikipedia.org/wiki/Barrel_(unit)The "bushel" is similar, and legal usage in the US seems to define it by weight of material.As a unit, "buckets" are rare, but seem to be defined as 4 gallons, and the "gallon" depends on which country defines it.

author: aduinstat
author_rank: Contributor
timestamp: October 14, 2022, 12:20:30 am
content: Miles are bullshit. The USA uses 3 different miles that are close to the same length, but slightly different.

author: james_s
author_rank: Super Contributor
timestamp: October 14, 2022, 12:30:25 am
content: Quote from: aduinstat on October 14, 2022, 12:20:30 amWe do? The only mile I'm familiar with is 5,280 feet.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: October 14, 2022, 01:13:14 am
content: NASA uses nautical miles (at least in their launch commentaries) 1 nautical mile = 6076 feet."Knots" are nautical miles per hour.

author: aduinstat
author_rank: Contributor
timestamp: October 14, 2022, 01:13:56 am
content: Quote from: james_s on October 14, 2022, 12:30:25 amWe also nautical miles which are about 6,076 feet (after 1954), and survey miles which are about 1/8 inch longer than an international mile.

author: IanB
author_rank: Super Contributor
timestamp: October 14, 2022, 02:41:36 am
content: Even if air watts is a recognized measurement, neither it nor anything else is really useful unless everyone quotes it in the same way so you can make comparisons. If Dyson gives a value for air watts and no other manufacturer does the same, then it is completely useless.Personally, I would be happy with something simple like air flow at the suction nozzle (cubic feet per minute in the USA or liters per second everywhere else). You are going to find that the vacuum with more air flow sucks better, because to get more air flow you need more suction.

author: TimFox
author_rank: Super Contributor
timestamp: October 14, 2022, 02:47:24 am
content: Quote from: aduinstat on October 14, 2022, 01:13:56 amThe US survey foot and survey mile (based on 1 meter = 39.37 inches exactly, the US definition before 1959) are being abandoned.The US statute mile is 5,280 feet (based on 1 inch = 2.54 cm exactly, the current US definition of the customary unit,not"imperial" unit).Nautical miles are an international standard, based on geodesy.The term "mile" comes from the latin for one thousand paces.

author: Someone
author_rank: Super Contributor
timestamp: October 14, 2022, 03:04:54 am
content: Quote from: IanB on October 14, 2022, 02:41:36 am"professional" vacuum units already provide figures for the (peak) airflow and pressure, but that's at the hose/port and the cleaning capacity/effectiveness then depends on the chosen head.How well a vacuum cleaner works? The EU has you covered: IEC/EN/BS/DIN 60312-1

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: October 14, 2022, 03:59:17 am
content: Hey, pardon my ignorance since vacuuming is the woman's job and all but what's the difference between paper bags and synthetic ones for a non-dyson?Other than being twice the price, why should I not just get the paper one?

author: Psi
author_rank: Super Contributor
timestamp: October 14, 2022, 04:13:29 am
content: Dyson is one of those brands that just pisses me of. So much arrogance.Apple being another.I just won't buy their stuff on principle.Even if it was the best option. (Which it isn't.)

author: VK3DRB
author_rank: Super Contributor
timestamp: October 14, 2022, 05:21:57 am
content: This is one of Dave's most entertaining videos about Dyson'smarketing. My favourite. If you have not seen it, watch right to the end - including AFTER the credits!

author: wraper
author_rank: Unknown
timestamp: October 14, 2022, 05:30:14 am
content: Quote from: IanB on October 14, 2022, 02:41:36 amThen they could make a vacuum with wider and shorter hose, optimize fan for that and claim higher airflow. But it would be worse at sucking dirt from carpets because of lower static pressure difference fan can produce.

author: tooki
author_rank: Super Contributor
timestamp: October 14, 2022, 05:33:55 am
content: Quote from: Ed.Kloonk on October 14, 2022, 03:59:17 amSynthetic bags supposedly have better filtration performance (both in particle size and in not getting clogged up) and airflow.My vacuum only takes synthetics so I can’t compare performance over paper, but what I can compare is price, and I can say with confidence that by shopping around (look at compatibility with other brands, which may be cheaper) you can get synthetic bags quite cheaply. (For example, mine is a Siemens, but essentially identical vaccines are sold under Bosch and other brand names. At any given time, one or another will be cheaper, have multipacks, etc.) There are third party bags too, but their price has never been below the best price I’ve found for original ones.

author: tooki
author_rank: Super Contributor
timestamp: October 14, 2022, 05:36:52 am
content: Quote from: thm_w on October 13, 2022, 11:19:06 pmPrice aside, Dyson products oftenfeelcheap: the plastic is rather soft, often unpainted. I’ve seen more than one Dyson upright vacuum fail because the plastic broke at the seam (I don’t know the technical term for it: where two flows of material meet during injection molding, and are supposed to fully fuse).I wanna say that AvE wasn’t super impressed by them in a teardown.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: October 14, 2022, 06:23:45 pm
content: I have a Dyson vacuum, and you're right, it does feel rather cheap. Every time I use it it feels like something is going to break off.

author: james_s
author_rank: Super Contributor
timestamp: October 14, 2022, 06:27:34 pm
content: Quote from: Psi on October 14, 2022, 04:13:29 amThe Project Farm video seemed like a fairly objective test to me, and the Dyson easily came out on top in many of the tests.I can't recall ever seeing any kind of advertising for them so I don't know what arrogance you're speaking of. I bought mine after using one that a friend had, it was so much better than the vacuum I had. I suspect you have never owned or used one.

author: PlainName
author_rank: Super Contributor
timestamp: October 14, 2022, 10:45:17 pm
content: Quote from: Ed.Kloonk on October 14, 2022, 03:59:17 amYou can throw a paper one away. With synthetic you empty the bags so you can reuse them, and that's when you figure bagless is the only vacuum you're going to get in future.

author: tooki
author_rank: Super Contributor
timestamp: October 14, 2022, 11:16:48 pm
content: Quote from: dunkemhigh on October 14, 2022, 10:45:17 pmNo, he’s talking about disposable synthetic vacuum bags.

author: PlainName
author_rank: Super Contributor
timestamp: October 14, 2022, 11:58:33 pm
content: You get cancelled if you let on you're destroying the climate with synthetic landfill.

author: Psi
author_rank: Super Contributor
timestamp: October 15, 2022, 01:48:39 am
content: Quote from: james_s on October 14, 2022, 06:27:34 pmFor Dyson, it's mainly the fact that they keep claiming they invented stuff which they did not. Or their terrible marketing lies.The radio controlled hobby industry pushed the development of tiny low cost high power brushless DC motors.Then other industries started using the same tech because it was much better. Like power tools.But Dyson made a big deal about saying they invented brand-new never before seen digital motor technology, when all they did was change their design to use the new brushless motor tech that already existed.RetractedThere was also many marketing lies.Like when they were calling their products 'zero carbon emissions' because the new brushless motors don't have brushes generating carbon dustThey just go way over the line with their attempts to trick customers into thinking they're the best. Same as Apple.

author: tooki
author_rank: Super Contributor
timestamp: October 15, 2022, 02:14:22 am
content: Quote from: dunkemhigh on October 14, 2022, 11:58:33 pmCan wenothave another of your digressions into absurdity, please?

author: Black Phoenix
author_rank: Super Contributor
timestamp: October 15, 2022, 02:23:26 am
content: Quote from: tooki on October 15, 2022, 02:14:22 amNo? But I just picked up the popcorn...

author: james_s
author_rank: Super Contributor
timestamp: October 15, 2022, 04:47:49 am
content: Quote from: Psi on October 15, 2022, 01:48:39 amBut by many measures the products objectively are the best. Same with Apple too, perfect? No, but better than most of what else is out there. I don't care about the marketing, I like my iPhone and I like my Dyson. Neither was particularly expensive, and both have been absolute bargains for the amount of use I've gotten out of them. I'm no fan of the rabid fanboys but I can't stand the rabid haters either, most of which have never even owned one of the products.

author: wraper
author_rank: Unknown
timestamp: October 15, 2022, 08:04:46 am
content: Quote from: Psi on October 15, 2022, 01:48:39 amDunno if they invented it or not but their "Diginal" motors are nothing like BLDC used in RC or power tools. No neodymium magnets inside. There is a magnet though but it isn't strong.

author: PlainName
author_rank: Super Contributor
timestamp: October 15, 2022, 10:55:11 am
content: Quote from: tooki on October 15, 2022, 02:14:22 amI was replying to Ed.K who often likes a bit of a joke. It was you that took it seriously enough to 'correct' me and then off we go again. Just lean back, have a cool drink and try not to be so pedantic.

author: tszaboo
author_rank: Super Contributor
timestamp: October 15, 2022, 11:23:41 am
content: Quote from: thm_w on October 13, 2022, 11:19:06 pmI'm just not sure why anyone would spend that much money on a device, that was obsoleted by the robot vacuum cleaners. It's like having the best and most efficient manual washing machine.

author: tooki
author_rank: Super Contributor
timestamp: October 15, 2022, 12:08:13 pm
content: Quote from: dunkemhigh on October 15, 2022, 10:55:11 amNo you weren’t, you were responding tome. Your reply followed my reply directly, so unless you use the quote function to quote what you’re replying to, then it is understood that you are referring to what comes immediately before.P.S. I don’t think pedantic means what you think it means…

author: PlainName
author_rank: Super Contributor
timestamp: October 15, 2022, 01:45:15 pm
content: Quote from: tszaboo on October 15, 2022, 11:23:41 amRobot vacuum cleaners aren't the final answer. We couldn't use one here, for instance. Well, I guess we could but we'd still need a normal vacuum to do the 80+% bits the robot one couldn't manage.

author: PlainName
author_rank: Super Contributor
timestamp: October 15, 2022, 01:47:27 pm
content: QuoteOh, FFS. You butted in so I thought you were playing along. Never mind: I shall just ignore your comments so I won't make that mistake again.

author: madires
author_rank: Super Contributor
timestamp: October 15, 2022, 03:36:49 pm
content: Quote from: thm_w on October 13, 2022, 11:19:06 pmMy sister has one of the fancy cordless Dyson vacs, especially for her dog. The Dyson manages the dog's hair well but I had the joy to take it apart a few times to clean hard to reach corners and fix some things. The vac isn't designed that well, cheap plastic, poor mechanics and other cut corners. Totally overpriced!

author: themadhippy
author_rank: Super Contributor
timestamp: October 15, 2022, 03:38:14 pm
content: Only vacuum worth having is a hoover junior.Simple design,dead easy to strip down,and individual parts available rather than changing a complete motor or beater bar.Added advantage there low power,250-300 watts, and often to do a better job than the 750w-1kw some of todays models use.

author: tooki
author_rank: Super Contributor
timestamp: October 15, 2022, 03:47:49 pm
content: Quote from: dunkemhigh on October 15, 2022, 01:47:27 pmI “butted in” to a discussion I was havingbeforeyou ever replied with your initial incorrect reply? Ok then…

author: Zoli
author_rank: Frequent Contributor
timestamp: October 15, 2022, 03:52:04 pm
content: Just to chime in: it is a reason why professionals considering Miele(to quote some commercial from them: "use now, and 30years from now the same vacuum" - true, as I saw in quite a few places) first in residential areas.And honestly, I'm surprised that so far nobody mentioned the brand.

author: strawberry
author_rank: Super Contributor
timestamp: October 15, 2022, 04:24:12 pm
content: AW(air watts) might be another way how to describe 1% power efficiencyQuote from: james_s on October 13, 2022, 07:20:30 am1/3 may come from reduced light outputL/W (lumen watts) is another . if remember correctly incandescent power efficiency ~0,5% and LED ~10%

author: PlainName
author_rank: Super Contributor
timestamp: October 15, 2022, 07:35:02 pm
content: QuoteDo they plaster their marketing with bullshit units? Well, then

author: Psi
author_rank: Super Contributor
timestamp: October 16, 2022, 12:53:38 am
content: Quote from: wraper on October 15, 2022, 08:04:46 amhm.. that's odd, I remember reading all about how it was standard brushless tech with a coat of paint.I wonder if I was tricked with a fake article or just had my wire crossed on that one.In any case, it seems i was wrong about that one.Statement retracted

author: Psi
author_rank: Super Contributor
timestamp: October 16, 2022, 01:07:02 am
content: Quote from: james_s on October 15, 2022, 04:47:49 amYeah, but not by the measures that matter to me.A product could be amazing at all it's intended use case while still being produced or marketed through dishonest practices.For me a product is only "good" if its a good product to use AND the company that created it acts in a positive way.(Or usually just not in a grossly negative way.)Quote from: james_s on October 15, 2022, 04:47:49 amI think that is really a matter of perspective and wealth, Apple and Dyson both make expensive products and I think most people would agree with that. I don't know much about the longevity of Dyson products which is very important when analyzing value for money. But it's very clear Apple products are engineered with zero effort to keep them running past the warrantee period or next product release.

author: ogden
author_rank: Super Contributor
timestamp: October 16, 2022, 02:12:16 am
content: Other manufacturers specify suction power simply in Watts. Air Watts is just fancy name for same measure - to give option for Dyson sales to convince that it is not

author: boB
author_rank: Frequent Contributor
timestamp: October 16, 2022, 02:24:04 am
content: There is power in the wind...For wind turbine use, the equation is, Power (W) = 0.6 x Cp x N x A x V^3Related I'm sure.

author: Psi
author_rank: Super Contributor
timestamp: October 16, 2022, 02:59:40 am
content: Quote from: ogden on October 16, 2022, 02:12:16 amYeah, that's a pretty common marketing practice.Invent a difference that doesn't exist, then use the difference to show how amazing your product is verses your competitors products.Usually done by companies when- There's no true benefits over the competitors products- When all the benefits that do exist over the competitors products are things no one cares about.- When investors want maximum returns at all costs and don't care what a company does as long as they can keep getting away with it.

author: wraper
author_rank: Unknown
timestamp: October 16, 2022, 06:59:35 am
content: Quote from: Psi on October 16, 2022, 02:59:40 amJust FYI Dyson did not invent air watts, and it is a proper unit of measure per ASTMhttps://tajhizkala.ir/doc/ASTM/ASTM%20F558__13.pdf. If some manufacturers drop "air" in the wording, it's not Dyson's fault. I rather think that two power ratings both labelled in watts cause more confusion to consumer.

author: ogden
author_rank: Super Contributor
timestamp: October 16, 2022, 08:07:34 am
content: Quote from: wraper on October 16, 2022, 06:59:35 amYeah, cannot argue. Thank you for pointer to ASTM doc.

author: rsjsouza
author_rank: Super Contributor
timestamp: October 16, 2022, 10:16:23 pm
content: Strictly to the topic of the thread, the bullshit is the motivation for the topic itself.To the discussion about Dyson, I echo other comments here regarding durability: having used one for about 14 years I found out its maintenance was not bad at all, with the occasional hair cleanup of the brush and the chamber filters. It was sold just because the missus wanted one with a HEPA filter.We also are on our second battery powered unit (the first one broke on a stupid accident after 10 years) and both work really well.Regarding the robotic stuff, I got very tired of having to unclog/clean the brushes and the dust compartment four or five times at every cleanup. It might work for a house with a single person but, when you have three long-haired girls, it is quite impractical.

author: Berni
author_rank: Super Contributor
timestamp: October 17, 2022, 05:17:27 am
content: Id say Air Watts are a good name because you don't want to confuse it with electrical Watts.Vacuum cleaners have had a watts number all over the box for a very long time, but this number was the watts of electrical input energy and it was obviously much larger. You wouldn't want costumers confusing the two since the electrical watts is a significantly bigger number.It is also perfectly possible that back then some manufacturers made less efficient motors on purpose just to get the watts number up. These motors have a ton of airflow trough them and i remember some vacuum cleaners blowing outright hot air out of them.

author: TheNewLab
author_rank: Frequent Contributor
timestamp: October 17, 2022, 05:33:39 am
content: OK This on e really hurts, I hit my head on the chair laughing. no acro for that is there.Quote from: boB on October 16, 2022, 02:24:04 amReadhttps://tajhizkala.ir/doc/ASTM/ASTM%20F558__13.pdfstill does not really inform say 95% of potential buyers..Why not something simple like PSI? or what HVAC techs use in testing vent draw and volume? I know Dyson makes great products, but "Air Watts" is. well, I read that entire PDF quickly and it is way more than I want to know. give me PSI and I understand right away

author: Berni
author_rank: Super Contributor
timestamp: October 17, 2022, 05:54:26 am
content: Problem is that fans/pumps have characteristic curves that can vary in shape a lot.It is easy to make a pump that makes a lot of pressure at low flow rate (this is a fridge compresor) and it is easy to make a pump that moves a lot of volume at very low pressure (this is a desk fan). Both of these beat a vacuum cleaner at pressure or volume. But what makes a vacuum cleaner a vacuum cleaner is that it can create a lot of pressure while simultaneously moving a lot of volume.Since air watts are pressure and volume multiplied together means that both of them have to be a large number for the result to be a large number. So it is actually a very smart way to measure the performance.