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Comparing the power consumption of a 30 year old refrigerator to a new one

217 points by furkansahin 1y ago

abraxas 1y ago
Energy Star appliances started to show up circa 1995 so there may have been comparably efficient fridges back then.
- stereo 1y ago
  The author is in Estonia. Appliances in the European Union have different energy standards and labels, and run on different voltages, so you don’t ever see Energy Star fridges there. Estonia joined the EU in 2004, and I don’t know what the energy labelling on appliances was like before then.
  - zikduruqe 1y ago
    According to Project 2025, we won't ever see them again. https://static.heritage.org/project2025/2025_MandateForLeadership_FULL.pdf#page=410 https://static.heritage.org/project2025/2025_MandateForLeade... "Eliminate energy efficiency standards for appliances. Pursuant to the Energy Policy and Conservation Act of 1975 as amended, the agency is required to set and periodically tighten energy and/or water efficiency standards for nearly all kinds of commercial and household appliances, including air conditioners, furnaces, water heaters, stoves, clothes washers and dryers, refrigerators, dishwashers, light bulbs, and showerheads. Current law and regulations reduce consumer choice, drive up costs for consumer appliances, and emphasize energy efficiency to the exclusion of other important factors such as cycle time and reparability." https://tonko.house.gov/uploadedfiles/project-2025-fact-sheet.pdf https://tonko.house.gov/uploadedfiles/project-2025-fact-shee...
someperson 1y ago
Since after 3 years you're beyond the break-even point due to energy use, the old refrigerator should be disposed of rather than given away. By keeping it in service, it's making somebody poorer. Especially since the person receiving the free 30 year old power hungry refrigerator and keeping it for a decade is the least likely to afford a replacement. Somebody already disadvantaged will eventually be stuck with structurally higher bills and find it harder to save due to this. Those that's not your problem it's more a government policy problem.
- avmich 1y ago
  It would be interesting to hear your comparison to counterarguments to this. Can you explain why these arguments are more important?
- emtel 1y ago
  Poor people can make their own decisions about whether to use an old fridge or not. They know much more about their own situation than you do. You are not well situated to make these sorts of decisions for them.
  - Johnny555 1y ago
    But do they? Does the person taking on that broken refrigerator know that it has a flaw that makes it consume so much electricity that in 3 years the power use alone would cost more than buying a brand new refrigerator? (ok, in this case they gave it to someone that needs a temporary 'fridge during renovations, so it's kind of a moot point, they aren't just giving it to "poor people")
    - b112 1y ago
      Probably not any better than the last two LG fridges which both broke due to compressor issues, causing me to lose $1k of food each time. In one case, during the high summer, I didn't notice one was slowly getting warmer. I had constant bowel problems, because I was eating rotten mayonnaise. This was compounded by the fact that I bought fancy spicy mayonnaise, which I'd never tasted before, which masked the rotten flavour. So -- my lessons learned, never by LG horrible fridges again, and keep an analog thermometer, which I bought for $5, in the fridge. (General FYI, LG has had more than one class action law suit because of their compressors, and, they even make it very hard to obtain replacements. Evil bastards.) My point is, you should take care with any fridge, new or old. (edit: some clarity on mayo)
      - RedShift1 1y ago
        You need to smell your food before you eat it. Trust your senses.
echelon_musk 1y ago
> Comparing the power consumption of a [broken] 30 year old refrigerator to a brand new one
- throw10920 1y ago
  Yeah, the title is misleading. The article says that one of the compressors on the old one was running constantly - if you applied the same failure mode to the new refrigerator, the difference would be significantly less.
  - quickthrowman 1y ago
    I would expect a refrigerator that has EC motors running the compressor(s) and fan(s) to be around 2-2.5x as efficient as one with fixed speed motors, based on what I know about variable frequency drives and three-phase induction motors. For those, 80% speed uses 50% of the power, 63% uses 25% of the power. For an 1800 rpm motor that is 1440 rpm and 1134 rpm. VFDs work well for most applications with variable torque (fans and pumps), but applications requiring constant torque (saws, grinders, etc) are better served by fixed speed starters.
    - amluto 1y ago
      > variable frequency drives and three-phase induction motors. For those, 80% speed uses 50% of the power, 63% uses 25% of the power. You’re presumably thinking of the “Affinity Laws”, which, according to Wikipedia (and plenty of other sources), “apply to pumps, fans, and hydraulic turbines. In these rotary implements, the affinity laws apply both to centrifugal and axial flows.” This is, IMO, one of the worst kinds of science writing. Wikipedia, and plenty of other sources, make little mention of when the do and don’t apply or, relatedly, why they’re true and why they can’t always be true. They generally apply to situations where a pump is pumping fluid through something like a filter or a long pipe where the pipe is a closed loop or at least the ends are at the same elevation (e.g. a swimming pool pump, except when pumping from a pool into a higher hot tub). So you have no actual work being done by moving fluid, and you can run the pump slower, and thus move less fluid per unit time, thus reducing friction in a manner that the pressure that the pump needs to overcome goes all the way to zero as the flow rate approaches zero. But the affinity laws are not really anything fundamental about pumps, and they certainly do not override conservation of energy. Now consider a refrigerator. The compressor is pumping refrigerant from an (approximately) fixed low pressure to a fixed high pressure. (The fluid goes back from high pressure to low pressure via a capillary tube or expansion valve or similar lossy device -- it gets its pressure increased in the gas phase and decreased in the liquid phase.) There's some friction, but after subtracting friction, the pressure is independent of flow rate, and thus the work done per unit flow is independent of flow rate, and the pump power scales linearly with flow as opposed to super-linearly as the affinity laws suggest. Also, the compressor is a positive-displacement pump, and the affinity laws don't even pretend to apply to these. (A well pump is another common system where the affinity laws will lead to nonsensical results. If you want to size a well pump properly, you need to know the height that you're raising the water, the output pressure you need, and the range of flows that you want. And then you look at the actual measured performance curves of the pumps (and their drives) that you are considering, and you pick something appropriate.) All that being said, variable-speed fridges exist, and they're kind of nice in that they try to run continuously and quietly instead of alternating between full-power (and loud) and all the way off. And they are probably a bit more efficient because there's less friction and because the motors are likely to be more efficient three-phase designs instead of the not-actually-amazing single-phase motors you'll find in older fridges.
roflchoppa 1y ago
I really want to know the power usage of the old fridge after it was fixed. :(
- cogman10 1y ago
  My assumption, probably pretty close to the new fridge. Very little has changed in fridge tech in 30 years besides them getting cheaper and breaking easier.
  - saltcured 1y ago
    For a fair comparison, they should measure a modern fridge when it misbehaving and running its WiFi and GPU constantly
  - simpsond 1y ago
    Is that true though? Better coolants, inverters / variable speed / scroll /swing compressors, insulation and mfg, etc. maybe for residential it’s less impactful, but refrigeration in general has better efficiency than 30 years ago.
    - cortic 1y ago
      > Better coolants The Montreal protocol (1987) put us back into the dark ages with coolants for a while (both with CFC ban and later phase outs of HFCs). I suspect if you tested a refrigerator from 40 years ago they would give modern ones a run for their money... It was obviously a worthwhile sacrifice for the ozone layer though.
  - parpfish 1y ago
    have there been improvements to the insulation? given how good high-end coolers are now, i'd assume that there's been something with the non-mechanical parts that could have improved
    - Ekaros 1y ago
      Maybe somewhat better insulation and then I have noticed with combined units that there is more of it. That is usable volume is smaller due to larger amount of insulation.
FabHK 1y ago
Why talk about 2.6 kWh/day (power*time/time = energy/time = power) when there is perfectly fine unit for that, namely the watt? 2.6 kWh/day = 2.6 kWh/24h = 108 W, on average.
- snet0 1y ago
  I've had this thought before, when seeing labels that talk about kWh/day. The answer is very simple: you pay per kWh. When people want to know power efficiency, what they really want to know is "how much will this cost me to run?". That answer is most easily expressed in kWh per unit time.
  - kitten_mittens_ 1y ago
    In the US, at least, there are some utilities that charge based on maximum kW (demand) and total kWh used (energy). ComEd in Chicago is a utility with a demand rate plan option.
    - tomrod 1y ago
      That tends to be commercial rates since businesses can have larger spikes in consumption, so the "pipe" needs to be larger. Industrial rates are similar. There are some like ComEd that you call out that can apply the model to residential rates, though my (now dated) experience is that they are rarer.
    - SECProto 1y ago
      Knowing the average of 108 W wouldn't help with knowing your peak demand, as fridges vary significantly from off to startup to running, so knowing the average isn't useful in that situation either.
      - bauruine 1y ago
        It would be completely wrong for peak demand. I had to learn this the hard way. While the small fridge I bought only uses 80 W while running the compressor uses 800W+ for a second on startup which was too much for my off the grid inverter.
agsamek 1y ago
My new Bosch 2020 refrigerator broke down after 3 years of usage. Coolant leakage. Not repairable due to the foam direct injection.
- anjel 1y ago
  Todays appliances are built, by design, to break fast these days. So whether old (operating costs) or new (foreshortened lifespan) your appliances cost you more. https://www.nytimes.com/wirecutter/reviews/modern-appliances-short-lifespan/ https://www.nytimes.com/wirecutter/reviews/modern-appliances... (https://ghostarchive.org/archive/KGf2Z https://ghostarchive.org/archive/KGf2Z)
  - trenchpilgrim 1y ago
    There are still some repairable brands. GE'a basic appliances (and their budget subbrands like Hotpoint) are a standout with excellent availability of parts and service data. A hotpoint electric range can be fixed by any homeowner with a screwdriver.
    - analog31 1y ago
      While we're on this topic, kudos to "Sears Parts Direct" for carrying a bewildering array of spare parts for those appliances.
      - SoftTalker 1y ago
        repairclinic.com is another good one. Not always the cheapest but very DIY-oriented.
    - anjel 1y ago
      The problem though is one of diminished durability by intent rather than repairability. Not to mention rising cost-of-repair.
    - dangus 1y ago
      As I recall GE is also one of the few/only brands that operates its own service business. I will also point out that the way inflation has tended to work is that you can still buy high quality appliances and other consumer products (e.g., tailored clothes and built-to-last leather shoes), but when you do the inflation math you have to spend a lot to get the equivalent product from decades ago. In other words, the same quality products generally still exist, the real issue is that a bunch of low price products that didn’t used to exist now do, and average people didn’t own as much stuff as they do now. If you buy a $2500 Speed Queen or a $10,000 Sub-Zero you’re getting the kind of quality and repairability that used to exist in more appliances. But when it comes to a $500 washing machine or dryer, when you adjust for inflation that product did not exist 40 years ago. The other thing I’ve heard about this issue is that the mid-range consumer luxury type stuff is the segment to avoid: built cheaply but with a lot of features that fail and a high cost. E.g., Samsung refrigerators with touch screens on them. You’ll notice that most true luxury built-in brands don’t have a laundry list of gimmick features.
aurizon 1y ago
The comments are well done and I am impressed. I would add the maker of the new one, partly as a tribute to them as well as gathering feedback from others. The fact that one compressors runs 24/7 might indicate it has failed to on 24/7 - also the ice block also says this? Thus a replacement thermostat might well reduce the KwHr used by the 24/7 operation. Looking up the model on youtube for thermostat repairs might help the new owner repair it and get a few more years, although an older less efficient unit, with a repaired thermostat it might not run 24/7 and use fewer KwHr?
woile 1y ago
A 21 kWh/month it's 252 kwh/annum (I guess?), which is around energy label E in the new EU energy labels. If you go for energy label A, some fridges have 101 kWh/annum, which is more than half less! I haven't seen many, and they are usually very tall, but hopefully we can see more and more in the future.
- deleted 1y ago
  [deleted]
- tgv 1y ago
  They're freaking expensive, though. I just replaced a (probably) 25 year old fridge by one with a D label. The difference with a C or E label is small in energy use. I do notice that the exterior gets really less warm than the old model. I don't think it would have qualified as an E. BTW, if I'm not mistaken, the energy label depends on the function. So 250kWh/yr could be (much) lower than E when the volume is smaller.
gdelfino01 1y ago
New ones break quickly and then consume zero energy. So then you buy an even newer one without caring at all about the emissions to buy the new one and to get rid of the old one. And then feel good to be "saving the planet" because you have a super efficient fridge and repeat the cycle.
- userbinator 1y ago
  Related item: https://news.ycombinator.com/item?id=32462954 https://news.ycombinator.com/item?id=32462954
- jeroenhd 1y ago
  Depends on what kind of fridge you buy. If you buy one for the price of a fridge in the "good old times" that doesn't come loaded with useless features, they last just fine. A lot of degrading quality in household appliances is the result of consumers buying the cheapest products that'll get the job done. Many people would rather risk having to buy two €600 fridges rather than buying one €1200 fridge (freezer sold separately of course). I can get a full fridge+freezer combination delivered to my home for €380. Of course that won't last as long as the €1200 equivalent from forty years ago, back when that was the normal price for a fridge.
ternus 1y ago
Totally fine to choose as the author did, but for others who might face a similar choice: repairing a thermostat in a fridge is dramatically easier than fixing almost anything in a dishwasher. I did that with my fridge - cost <$20 for the part and maybe 30 minutes of work. Your (EU) kilometrage may vary. I suspect the power savings would be much less dramatic with a fixed thermostat.
- analog31 1y ago
  Indeed, been there. Just getting the dishwasher out of its cubby hole is a major effort, and involves dealing with not just the wiring but the hoses too. And if it's an older house, chances are good that the dishwasher had to be crammed in with a certain amount of hacking, cussing, and persuasion. The fridge rolls out into the room on its own wheels.
  - aidos 1y ago
    Amen. I put my dishwasher in myself so I get to curse myself for that hacking. Worst was sourcing the parts though. Getting the thing out, effectively getting it up on blocks to run it and see the issue was hard work. Getting the specific totally non-standard o-ring size out of the manufacturer was impossible. In the end I resorted to siliconing but I just cannot dump something like that over a 5c part.
  - ternus 1y ago
    Many dishwashers are supposed to be wood-screwed into the surrounding cabinets! Recently installed one for a friend and was surprised to see that instruction. Meanwhile, with the exception of ice makers/water dispensers (1/4 PEX), fridges don't have to deal with hoses for the most part. So much easier IME.
    - SoftTalker 1y ago
      > Many dishwashers are supposed to be wood-screwed into the surrounding cabinets! That's so they don't tip forward when a rack loaded with dishes is pulled out. There's a fair bit of forward leverage in that weight distribution.
ctrlp 1y ago
Regardless of efficiency, it is very difficult to find a newer refrigerator whose compressor doesn't emit a very irritating high pitched whine almost continuously.
- jrmg 1y ago
  Personal pet level is that it’s so hard to get information on the noise level of appliances. We’ve recently moved, and our new house’s crawl space has a Santa Fe dehumidifier in it that seems SO LOUD at night. I don’t think it’s broken - it’s just a compressor and fan with no engineering put into keeping them quiet. If I could get one that was as efficient and well built, but I knew would be quiet, I’d replace it in a heartbeat - but manufacturers don’t advertise noise levels. Surely I can’t be the only one who’d pay substantially more for an appliance that was guaranteed to be quiet?
  - reddalo 1y ago
    >it’s so hard to get information on the noise level of appliances It's super easy if you live in the European Union, thanks to the Energy Label [1] which is mandatory on every appliance. [1] https://energy-efficient-products.ec.europa.eu/ecodesign-and-energy-label/understanding-energy-label_en https://energy-efficient-products.ec.europa.eu/ecodesign-and...
    - jrmg 1y ago
      It says that’s ‘supplementary’ information that ‘can’ be provided. Is it actually done?
- bob1029 1y ago
  I would try plugging a simple induction motor into the refrigerator circuit to see if it also makes a weird noise. It's possible you have a problem with the wiring itself (loose neutral, etc.). I've never had issues with HF noise out of a refrigerator. It's always been the opposite kind of noise that has been a problem.
- silvestrov 1y ago
prmoustache 1y ago
The dramatic things with refrigerators is that in most countries people will install them in the kitchen for obvious practicality reasons, which is often also the hottest room of the house/appartment due to ovens, stoves and spending a significant amount of time there. If you think of it, it is bonkers that we put a device meant to keep stuff cold in what is a heated place in northern countries. Some hold houses and building used to have non heated dedicated rooms meant to keep food at a lower temperature naturally in winter but this has pretty much disappeared. OTOH I live in a coastal city in south of Spain and every time I read a label that said food shouldn't be in a fridge but kept in a fresh and dry storage I ask myself where the eff should I store it there is no place like that unless I am running aircon 24/7 which I certainly won't do.
- JumpCrisscross 1y ago
  > kept in a fresh and dry storage I ask myself where the eff should I store it Your mountain home. (I'd hazard a guess that many such products come from the interior versus humid coasts.)
- rz2k 1y ago
  I Suppose heating fuel is cheaper, or household heat pumps are more efficient, but all of the energy consumed by running the refrigerator becomes waste heat in the same room you are trying to heat. That seems superior to the refrigerator heating a room where the waste heat isn’t useful.
- fifilura 1y ago
  Where do you store your wine? (Only half kidding, but I am sure you have solutions like this in Spain)
  - prmoustache 1y ago
    well I don't have one, I rarely ever drink wine at home, but there are dedicated devices for that, I think they are called wine cabinets in english? They could be used to store other things indeed. I have never looked at the energy consumption of these things.
guerby 1y ago
I got a rated "A" for one year, this model (256 liter fridge + 122 liter freezer) : https://eprel.ec.europa.eu/screen/product/refrigeratingappliances2019/1366899 https://eprel.ec.europa.eu/screen/product/refrigeratingappli... Rated for 113 kWh/year I left a powermeter on it for one year and got 130 kWh. It's amazing that the average power consumption is less than 15 Watt.
sitharus 1y ago
I (well, my landlord) replaced a similarly old refrigerator last year. The thermostat was fine, it had developed a very slow gas leak and the charge had dropped enough that it was freezing rather than cooling. It was using around 29kWh/month before the leak was noticeable, the new one uses 12kWh/month. The new one is slightly larger than the old. The old model was freezer-on-top style, the new one is a less efficient freezer below model. Hopefully the new one lasts as long as the old!
shtzvhdx 1y ago
Since a fridge's compressor runs about 30% of the time, most of the energy savings of the new fridge are because of a new thermostat. But the new fridge will not last thirty. Heck, he's lucky if it lasts ten. Five if he lives in an area prone to electrical surges.
- xxs 1y ago
  >Five if he lives in an area prone to electrical surges. Many fridges have DC compressors and decent enough input filtering, that should be no issue. However, the electronics themselves are another matter. Most fridges nowadays have defrost cycles controlled by the said processors, with the latter being prone to even software issues. Some fans may not need a replacement, while the fans are cheap and ubiquitous reaching them is another story.
ohman876 1y ago
The article mentions ice building up in that old fridge, and this reminded me what I was told by a man who was fixing these things- that the condition of rubber seal and fridge not being leveled correctly can also lead to the ice buildup (if thermostat is not broken). He did not explain in deep technical details why, but said that when the fridge door is not sealing fully then the room air enters the fridge and due to different condensation point it causes moisture buildup at the coldest part. I am not sure how factual this was, since after hearing this I adjusted the fridge so the doors were always closing themselves thanks to gravity, and the ice still kept building up. I did not replace the seal though :)
d_sem 1y ago
So can we project from the authors data that, under normal operation, both bridges roughly consume the same amount of power?
userbinator 1y ago
Agree with the others here that this is absolutely not a fair comparison. Most likely the door of the old one was not sealing well, hence the continuous running and frost buildup. I have a late 30s Frigidaire that I restored a few years ago which has been taking around 200kWh/y (70W compressor, ~33% duty cycle.)
- koolba 1y ago
  > I have a late 30s Frigidaire that I restored a few years ago Did I read that right with 30s, as in 1930s?
  - userbinator 1y ago
    Not sure of the exact year, but it should be around 1936-1940.
- mmooss 1y ago
  > not a fair comparison. Most likely the door of the old one was not sealing well, hence the continuous running and frost buildup That's an expected cost of old fridges, so I don't know that it's unfair. A major reason old machines are less efficient is accumulated defects (people too!). If I said comparing a new car's fuel efficiency to my old one was unfair, because my old one has a lot of problems, you might say that's very fair.
  - chii 1y ago
    it depends on why and exact purpose of said comparison. If the comparison is meant to show the drop in efficiency as part of age and usage, then yes. However, if you wanted to _only_ compare design upgrades, you don't want wear and tear to confound the results.
    - tonyhart7 1y ago
      but you cant compare only design ???? there is no one selling an 30 year old fridge "new"
bfkwlfkjf 1y ago
Anybody know how the author collected the energy consumption data?
- ranger207 1y ago
  From a link in TFA: https://ounapuu.ee/posts/2024/05/02/smartplugs/ https://ounapuu.ee/posts/2024/05/02/smartplugs/
  - bfkwlfkjf 1y ago
    Thank you for the link. May I ask what TFA means though?
    - janfoeh 1y ago
      It is a commonly used abbreviation for "the f...ine article". On discussion sites of the Internet of yore, people would tell you to RTFA — "read the fucking article" — when it appeared you were chiming in without having first read the item under discussion. This is an extraction from that.
codedokode 1y ago
Electricity is so cheap (8-9 cents per kWh), it doesn't even make sense to invest in saving it. I would any day choose a cheaper product over 20% more expensive one that uses 10% less power.
- russelg 1y ago
  And if you didn't live in a place where it's cheap?
  - codedokode 1y ago
    Then one need to do the calculations and decide based on that. One should also remember that the product might break so if it repays it cost over many years, there is a chance it breaks long before that. However, LED light bulbs are worth buying, the cheap ones (less than $3) repay their price in several months even with our electricity pricing.
- foofoo12 1y ago
  Electricity prices varies a LOT depending where in the world you are: https://worldpopulationreview.com/country-rankings/cost-of-electricity-by-country https://worldpopulationreview.com/country-rankings/cost-of-e...
  - codedokode 1y ago
    I wonder why it is so expensive (46 cents) in Italy when other EU countries have lower prices. Taxes? Monopoly? Corruption? And why China has cheap electricity? They don't have much oil. Could it be that electricity price is based not on real expenses, but simply on "how much they can pay" principle? Anyway, Western Europe stands out as a dark spot on mostly light-colored map.
    - jansper39 1y ago
      There are huge differences between generation types, infrastructure requirements, regulatory environments, subsidies and ownership of electrical generation and supply equipment's before you even get into conspiratorial thinking. Globally, most electricity is not generated via oil anyway. China has cheap energy in part because they have a planned economy and a large usage of cheap energy sources such as solar and coal.
calmbonsai 1y ago
Well, um, yeah. If you're comparing anything to crap it will be better than...crap.
senectus1 1y ago
years ago we were renting a property that came with a fridge.. and our electricity bills where huge. I turned it off and our power bills more than halved. It was enough for us to buy a new fridge and barely notice the powerbills change after that
nakamoto_damacy 1y ago
Nobody talking about the refrigerators in Europe. They work differently. The ice forms inside the fridge part not just the freezer part. I don't know why and have not looked into it but it is in every fridge, including brand new ones.
- jeroenhd 1y ago
  Ice forming inside of the fridge is a result of moisture making its way into the fridge and staying in contact with the cooling elements. The cause can be a lot of things, from broken drain pipes to damaged door seals. A well-functioning fridge shouldn't have (much) ice buildup unless you live in a hot and humid area. Some modern fridges (usually the luxury models) also have features to defrost themselves if they detect that there may be frost buildup, but many fridges still have you do it manually.
rpcope1 1y ago
One thing that catches my eye here is the use of a smart plug on the refrigerator for current monitoring. I've tried a ton of different ones including the "good" ones like Shelly, and they all seem to use shunt resistors to gauge power draw. It would make me really nervous to use something like that to measure power draw on a big inductive load like a fridge. It's a shame, I've never seen a current clamp in plug form with no on/off switch, so you've basically gotta do some fab work, but that's basically really the only safe way to collect current data for anything that pulls a non-trivial amount of power.
- thekoma 1y ago
  Can you elaborate a bit further on what you’d need to do and why? It’s been a while since my electrical courses. I’ve been trying to measure home power consumption with these plugs (and the ones from IKEA) but I’ve been getting suspicious readings for inductive loads.
  - jeroenhd 1y ago
    The IKEA plugs have a tidbit in the manual that says a "motor load" is limited to 300W while a resistive load can reach the full 3680W (at 230V, probably less if you're in a lower voltage country). Should be fine for modern fridges but older fridges may overwhelm the circuitry.
  - rpcope1 1y ago
    I wouldn't bother using a smart plug. The other thing that's real dangerous about them that I didn't really elaborate on is the relay. There's a reason on something like a pump, fridge, AC unit, etc. you'd see a real contactor instead of a relay, and it's because relays are inappropriate and have dangerous failure modes for big loads like that and are typically way too small. In most real non-resi situations, you'd probably isolate the hot leg and put a good CT (current clamp) on it and read that. The great thing about that is you haven't added anything in the power path for the device, like a shunt which is what most smart plugs use. Current clamps are good for a lot more current (though I guess a proper shunt could do it too). The easiest way to do this in your setting is to find a good UL-listed electrical box with cable glands, a short piece of DIN rail, a male and female plug pigtail, some proper THHN wire and wirenets and a Shelly 50A EM Pro, and just graft the EM Pro into the box and wire it up with it's CT. You've now got something signficantly more durable and probably safer (and correctly specced for the load). I've done other things like using an HV Labjack and some good CTs or other one or few off designs. There's lots of stuff in the commercial/industrial space that does this well but it tends to be $$$. Again, for the sake of my own family, I wouldn't use non-UL stuff (most plugs and things that go in gangboxes that are "smart" aren't UL listed, and MAYBE are ETL) as you who knows how much or how well it's tested.
johnnyApplePRNG 1y ago
>assuming that it doesn’t break down. Ha! Good luck with that. The last time I bought a brand new freezer... it died in under 5 years... can't remember the brand... some asian import to Canada here. I went out and bought a used kenmore I think it was off of Marketplace... >15 years old and it lasted longer than the brand new one did... at 1/4 the price! These were both chest freezers and besides it's compressor being slightly louder, I doubt it used much more energy at all. If anything, it was probably insulated better, and used less I would imagine. It was much heavier, at least.
casey2 1y ago
If you have to buy 5+ refrigerators in the time the old one you are likely doing more harm to the environment than marginally more electricity consumption

217 points by furkansahin 1y ago

abraxas 1y ago

Energy Star appliances started to show up circa 1995 so there may have been comparably efficient fridges back then.

stereo 1y ago
The author is in Estonia. Appliances in the European Union have different energy standards and labels, and run on different voltages, so you don’t ever see Energy Star fridges there. Estonia joined the EU in 2004, and I don’t know what the energy labelling on appliances was like before then.
- zikduruqe 1y ago
  According to Project 2025, we won't ever see them again. https://static.heritage.org/project2025/2025_MandateForLeadership_FULL.pdf#page=410 https://static.heritage.org/project2025/2025_MandateForLeade... "Eliminate energy efficiency standards for appliances. Pursuant to the Energy Policy and Conservation Act of 1975 as amended, the agency is required to set and periodically tighten energy and/or water efficiency standards for nearly all kinds of commercial and household appliances, including air conditioners, furnaces, water heaters, stoves, clothes washers and dryers, refrigerators, dishwashers, light bulbs, and showerheads. Current law and regulations reduce consumer choice, drive up costs for consumer appliances, and emphasize energy efficiency to the exclusion of other important factors such as cycle time and reparability." https://tonko.house.gov/uploadedfiles/project-2025-fact-sheet.pdf https://tonko.house.gov/uploadedfiles/project-2025-fact-shee...

someperson 1y ago

Since after 3 years you're beyond the break-even point due to energy use, the old refrigerator should be disposed of rather than given away. By keeping it in service, it's making somebody poorer. Especially since the person receiving the free 30 year old power hungry refrigerator and keeping it for a decade is the least likely to afford a replacement. Somebody already disadvantaged will eventually be stuck with structurally higher bills and find it harder to save due to this. Those that's not your problem it's more a government policy problem.

avmich 1y ago
It would be interesting to hear your comparison to counterarguments to this. Can you explain why these arguments are more important?
emtel 1y ago
Poor people can make their own decisions about whether to use an old fridge or not. They know much more about their own situation than you do. You are not well situated to make these sorts of decisions for them.
- Johnny555 1y ago
  But do they? Does the person taking on that broken refrigerator know that it has a flaw that makes it consume so much electricity that in 3 years the power use alone would cost more than buying a brand new refrigerator? (ok, in this case they gave it to someone that needs a temporary 'fridge during renovations, so it's kind of a moot point, they aren't just giving it to "poor people")
  - b112 1y ago
    Probably not any better than the last two LG fridges which both broke due to compressor issues, causing me to lose $1k of food each time. In one case, during the high summer, I didn't notice one was slowly getting warmer. I had constant bowel problems, because I was eating rotten mayonnaise. This was compounded by the fact that I bought fancy spicy mayonnaise, which I'd never tasted before, which masked the rotten flavour. So -- my lessons learned, never by LG horrible fridges again, and keep an analog thermometer, which I bought for $5, in the fridge. (General FYI, LG has had more than one class action law suit because of their compressors, and, they even make it very hard to obtain replacements. Evil bastards.) My point is, you should take care with any fridge, new or old. (edit: some clarity on mayo)
    - RedShift1 1y ago
      You need to smell your food before you eat it. Trust your senses.

echelon_musk 1y ago

> Comparing the power consumption of a [broken] 30 year old refrigerator to a brand new one

throw10920 1y ago
Yeah, the title is misleading. The article says that one of the compressors on the old one was running constantly - if you applied the same failure mode to the new refrigerator, the difference would be significantly less.
- quickthrowman 1y ago
  I would expect a refrigerator that has EC motors running the compressor(s) and fan(s) to be around 2-2.5x as efficient as one with fixed speed motors, based on what I know about variable frequency drives and three-phase induction motors. For those, 80% speed uses 50% of the power, 63% uses 25% of the power. For an 1800 rpm motor that is 1440 rpm and 1134 rpm. VFDs work well for most applications with variable torque (fans and pumps), but applications requiring constant torque (saws, grinders, etc) are better served by fixed speed starters.
  - amluto 1y ago
    > variable frequency drives and three-phase induction motors. For those, 80% speed uses 50% of the power, 63% uses 25% of the power. You’re presumably thinking of the “Affinity Laws”, which, according to Wikipedia (and plenty of other sources), “apply to pumps, fans, and hydraulic turbines. In these rotary implements, the affinity laws apply both to centrifugal and axial flows.” This is, IMO, one of the worst kinds of science writing. Wikipedia, and plenty of other sources, make little mention of when the do and don’t apply or, relatedly, why they’re true and why they can’t always be true. They generally apply to situations where a pump is pumping fluid through something like a filter or a long pipe where the pipe is a closed loop or at least the ends are at the same elevation (e.g. a swimming pool pump, except when pumping from a pool into a higher hot tub). So you have no actual work being done by moving fluid, and you can run the pump slower, and thus move less fluid per unit time, thus reducing friction in a manner that the pressure that the pump needs to overcome goes all the way to zero as the flow rate approaches zero. But the affinity laws are not really anything fundamental about pumps, and they certainly do not override conservation of energy. Now consider a refrigerator. The compressor is pumping refrigerant from an (approximately) fixed low pressure to a fixed high pressure. (The fluid goes back from high pressure to low pressure via a capillary tube or expansion valve or similar lossy device -- it gets its pressure increased in the gas phase and decreased in the liquid phase.) There's some friction, but after subtracting friction, the pressure is independent of flow rate, and thus the work done per unit flow is independent of flow rate, and the pump power scales linearly with flow as opposed to super-linearly as the affinity laws suggest. Also, the compressor is a positive-displacement pump, and the affinity laws don't even pretend to apply to these. (A well pump is another common system where the affinity laws will lead to nonsensical results. If you want to size a well pump properly, you need to know the height that you're raising the water, the output pressure you need, and the range of flows that you want. And then you look at the actual measured performance curves of the pumps (and their drives) that you are considering, and you pick something appropriate.) All that being said, variable-speed fridges exist, and they're kind of nice in that they try to run continuously and quietly instead of alternating between full-power (and loud) and all the way off. And they are probably a bit more efficient because there's less friction and because the motors are likely to be more efficient three-phase designs instead of the not-actually-amazing single-phase motors you'll find in older fridges.

roflchoppa 1y ago

I really want to know the power usage of the old fridge after it was fixed. :(

cogman10 1y ago
My assumption, probably pretty close to the new fridge. Very little has changed in fridge tech in 30 years besides them getting cheaper and breaking easier.
- saltcured 1y ago
  For a fair comparison, they should measure a modern fridge when it misbehaving and running its WiFi and GPU constantly
- simpsond 1y ago
  Is that true though? Better coolants, inverters / variable speed / scroll /swing compressors, insulation and mfg, etc. maybe for residential it’s less impactful, but refrigeration in general has better efficiency than 30 years ago.
  - cortic 1y ago
    > Better coolants The Montreal protocol (1987) put us back into the dark ages with coolants for a while (both with CFC ban and later phase outs of HFCs). I suspect if you tested a refrigerator from 40 years ago they would give modern ones a run for their money... It was obviously a worthwhile sacrifice for the ozone layer though.
- parpfish 1y ago
  have there been improvements to the insulation? given how good high-end coolers are now, i'd assume that there's been something with the non-mechanical parts that could have improved
  - Ekaros 1y ago
    Maybe somewhat better insulation and then I have noticed with combined units that there is more of it. That is usable volume is smaller due to larger amount of insulation.

FabHK 1y ago

Why talk about 2.6 kWh/day (power*time/time = energy/time = power) when there is perfectly fine unit for that, namely the watt? 2.6 kWh/day = 2.6 kWh/24h = 108 W, on average.

snet0 1y ago
I've had this thought before, when seeing labels that talk about kWh/day. The answer is very simple: you pay per kWh. When people want to know power efficiency, what they really want to know is "how much will this cost me to run?". That answer is most easily expressed in kWh per unit time.
- kitten_mittens_ 1y ago
  In the US, at least, there are some utilities that charge based on maximum kW (demand) and total kWh used (energy). ComEd in Chicago is a utility with a demand rate plan option.
  - tomrod 1y ago
    That tends to be commercial rates since businesses can have larger spikes in consumption, so the "pipe" needs to be larger. Industrial rates are similar. There are some like ComEd that you call out that can apply the model to residential rates, though my (now dated) experience is that they are rarer.
  - SECProto 1y ago
    Knowing the average of 108 W wouldn't help with knowing your peak demand, as fridges vary significantly from off to startup to running, so knowing the average isn't useful in that situation either.
    - bauruine 1y ago
      It would be completely wrong for peak demand. I had to learn this the hard way. While the small fridge I bought only uses 80 W while running the compressor uses 800W+ for a second on startup which was too much for my off the grid inverter.

agsamek 1y ago

My new Bosch 2020 refrigerator broke down after 3 years of usage. Coolant leakage. Not repairable due to the foam direct injection.

anjel 1y ago
Todays appliances are built, by design, to break fast these days. So whether old (operating costs) or new (foreshortened lifespan) your appliances cost you more. https://www.nytimes.com/wirecutter/reviews/modern-appliances-short-lifespan/ https://www.nytimes.com/wirecutter/reviews/modern-appliances... (https://ghostarchive.org/archive/KGf2Z https://ghostarchive.org/archive/KGf2Z)
- trenchpilgrim 1y ago
  There are still some repairable brands. GE'a basic appliances (and their budget subbrands like Hotpoint) are a standout with excellent availability of parts and service data. A hotpoint electric range can be fixed by any homeowner with a screwdriver.
  - analog31 1y ago
    While we're on this topic, kudos to "Sears Parts Direct" for carrying a bewildering array of spare parts for those appliances.
    - SoftTalker 1y ago
      repairclinic.com is another good one. Not always the cheapest but very DIY-oriented.
  - anjel 1y ago
    The problem though is one of diminished durability by intent rather than repairability. Not to mention rising cost-of-repair.
  - dangus 1y ago
    As I recall GE is also one of the few/only brands that operates its own service business. I will also point out that the way inflation has tended to work is that you can still buy high quality appliances and other consumer products (e.g., tailored clothes and built-to-last leather shoes), but when you do the inflation math you have to spend a lot to get the equivalent product from decades ago. In other words, the same quality products generally still exist, the real issue is that a bunch of low price products that didn’t used to exist now do, and average people didn’t own as much stuff as they do now. If you buy a $2500 Speed Queen or a $10,000 Sub-Zero you’re getting the kind of quality and repairability that used to exist in more appliances. But when it comes to a $500 washing machine or dryer, when you adjust for inflation that product did not exist 40 years ago. The other thing I’ve heard about this issue is that the mid-range consumer luxury type stuff is the segment to avoid: built cheaply but with a lot of features that fail and a high cost. E.g., Samsung refrigerators with touch screens on them. You’ll notice that most true luxury built-in brands don’t have a laundry list of gimmick features.

aurizon 1y ago

The comments are well done and I am impressed. I would add the maker of the new one, partly as a tribute to them as well as gathering feedback from others. The fact that one compressors runs 24/7 might indicate it has failed to on 24/7 - also the ice block also says this? Thus a replacement thermostat might well reduce the KwHr used by the 24/7 operation. Looking up the model on youtube for thermostat repairs might help the new owner repair it and get a few more years, although an older less efficient unit, with a repaired thermostat it might not run 24/7 and use fewer KwHr?

woile 1y ago

A 21 kWh/month it's 252 kwh/annum (I guess?), which is around energy label E in the new EU energy labels. If you go for energy label A, some fridges have 101 kWh/annum, which is more than half less! I haven't seen many, and they are usually very tall, but hopefully we can see more and more in the future.

deleted 1y ago
[deleted]
tgv 1y ago
They're freaking expensive, though. I just replaced a (probably) 25 year old fridge by one with a D label. The difference with a C or E label is small in energy use. I do notice that the exterior gets really less warm than the old model. I don't think it would have qualified as an E. BTW, if I'm not mistaken, the energy label depends on the function. So 250kWh/yr could be (much) lower than E when the volume is smaller.

gdelfino01 1y ago

New ones break quickly and then consume zero energy. So then you buy an even newer one without caring at all about the emissions to buy the new one and to get rid of the old one. And then feel good to be "saving the planet" because you have a super efficient fridge and repeat the cycle.

userbinator 1y ago
Related item: https://news.ycombinator.com/item?id=32462954 https://news.ycombinator.com/item?id=32462954
jeroenhd 1y ago
Depends on what kind of fridge you buy. If you buy one for the price of a fridge in the "good old times" that doesn't come loaded with useless features, they last just fine. A lot of degrading quality in household appliances is the result of consumers buying the cheapest products that'll get the job done. Many people would rather risk having to buy two €600 fridges rather than buying one €1200 fridge (freezer sold separately of course). I can get a full fridge+freezer combination delivered to my home for €380. Of course that won't last as long as the €1200 equivalent from forty years ago, back when that was the normal price for a fridge.

ternus 1y ago

Totally fine to choose as the author did, but for others who might face a similar choice: repairing a thermostat in a fridge is dramatically easier than fixing almost anything in a dishwasher. I did that with my fridge - cost <$20 for the part and maybe 30 minutes of work. Your (EU) kilometrage may vary. I suspect the power savings would be much less dramatic with a fixed thermostat.

analog31 1y ago
Indeed, been there. Just getting the dishwasher out of its cubby hole is a major effort, and involves dealing with not just the wiring but the hoses too. And if it's an older house, chances are good that the dishwasher had to be crammed in with a certain amount of hacking, cussing, and persuasion. The fridge rolls out into the room on its own wheels.
- aidos 1y ago
  Amen. I put my dishwasher in myself so I get to curse myself for that hacking. Worst was sourcing the parts though. Getting the thing out, effectively getting it up on blocks to run it and see the issue was hard work. Getting the specific totally non-standard o-ring size out of the manufacturer was impossible. In the end I resorted to siliconing but I just cannot dump something like that over a 5c part.
- ternus 1y ago
  Many dishwashers are supposed to be wood-screwed into the surrounding cabinets! Recently installed one for a friend and was surprised to see that instruction. Meanwhile, with the exception of ice makers/water dispensers (1/4 PEX), fridges don't have to deal with hoses for the most part. So much easier IME.
  - SoftTalker 1y ago
    > Many dishwashers are supposed to be wood-screwed into the surrounding cabinets! That's so they don't tip forward when a rack loaded with dishes is pulled out. There's a fair bit of forward leverage in that weight distribution.

ctrlp 1y ago

Regardless of efficiency, it is very difficult to find a newer refrigerator whose compressor doesn't emit a very irritating high pitched whine almost continuously.

jrmg 1y ago
Personal pet level is that it’s so hard to get information on the noise level of appliances. We’ve recently moved, and our new house’s crawl space has a Santa Fe dehumidifier in it that seems SO LOUD at night. I don’t think it’s broken - it’s just a compressor and fan with no engineering put into keeping them quiet. If I could get one that was as efficient and well built, but I knew would be quiet, I’d replace it in a heartbeat - but manufacturers don’t advertise noise levels. Surely I can’t be the only one who’d pay substantially more for an appliance that was guaranteed to be quiet?
- reddalo 1y ago
  >it’s so hard to get information on the noise level of appliances It's super easy if you live in the European Union, thanks to the Energy Label [1] which is mandatory on every appliance. [1] https://energy-efficient-products.ec.europa.eu/ecodesign-and-energy-label/understanding-energy-label_en https://energy-efficient-products.ec.europa.eu/ecodesign-and...
  - jrmg 1y ago
    It says that’s ‘supplementary’ information that ‘can’ be provided. Is it actually done?
bob1029 1y ago
I would try plugging a simple induction motor into the refrigerator circuit to see if it also makes a weird noise. It's possible you have a problem with the wiring itself (loose neutral, etc.). I've never had issues with HF noise out of a refrigerator. It's always been the opposite kind of noise that has been a problem.
silvestrov 1y ago

prmoustache 1y ago

The dramatic things with refrigerators is that in most countries people will install them in the kitchen for obvious practicality reasons, which is often also the hottest room of the house/appartment due to ovens, stoves and spending a significant amount of time there. If you think of it, it is bonkers that we put a device meant to keep stuff cold in what is a heated place in northern countries. Some hold houses and building used to have non heated dedicated rooms meant to keep food at a lower temperature naturally in winter but this has pretty much disappeared. OTOH I live in a coastal city in south of Spain and every time I read a label that said food shouldn't be in a fridge but kept in a fresh and dry storage I ask myself where the eff should I store it there is no place like that unless I am running aircon 24/7 which I certainly won't do.

JumpCrisscross 1y ago
> kept in a fresh and dry storage I ask myself where the eff should I store it Your mountain home. (I'd hazard a guess that many such products come from the interior versus humid coasts.)
rz2k 1y ago
I Suppose heating fuel is cheaper, or household heat pumps are more efficient, but all of the energy consumed by running the refrigerator becomes waste heat in the same room you are trying to heat. That seems superior to the refrigerator heating a room where the waste heat isn’t useful.
fifilura 1y ago
Where do you store your wine? (Only half kidding, but I am sure you have solutions like this in Spain)
- prmoustache 1y ago
  well I don't have one, I rarely ever drink wine at home, but there are dedicated devices for that, I think they are called wine cabinets in english? They could be used to store other things indeed. I have never looked at the energy consumption of these things.

guerby 1y ago

I got a rated "A" for one year, this model (256 liter fridge + 122 liter freezer) : https://eprel.ec.europa.eu/screen/product/refrigeratingappliances2019/1366899 https://eprel.ec.europa.eu/screen/product/refrigeratingappli... Rated for 113 kWh/year I left a powermeter on it for one year and got 130 kWh. It's amazing that the average power consumption is less than 15 Watt.

sitharus 1y ago

I (well, my landlord) replaced a similarly old refrigerator last year. The thermostat was fine, it had developed a very slow gas leak and the charge had dropped enough that it was freezing rather than cooling. It was using around 29kWh/month before the leak was noticeable, the new one uses 12kWh/month. The new one is slightly larger than the old. The old model was freezer-on-top style, the new one is a less efficient freezer below model. Hopefully the new one lasts as long as the old!

shtzvhdx 1y ago

Since a fridge's compressor runs about 30% of the time, most of the energy savings of the new fridge are because of a new thermostat. But the new fridge will not last thirty. Heck, he's lucky if it lasts ten. Five if he lives in an area prone to electrical surges.

xxs 1y ago
>Five if he lives in an area prone to electrical surges. Many fridges have DC compressors and decent enough input filtering, that should be no issue. However, the electronics themselves are another matter. Most fridges nowadays have defrost cycles controlled by the said processors, with the latter being prone to even software issues. Some fans may not need a replacement, while the fans are cheap and ubiquitous reaching them is another story.

ohman876 1y ago

The article mentions ice building up in that old fridge, and this reminded me what I was told by a man who was fixing these things- that the condition of rubber seal and fridge not being leveled correctly can also lead to the ice buildup (if thermostat is not broken). He did not explain in deep technical details why, but said that when the fridge door is not sealing fully then the room air enters the fridge and due to different condensation point it causes moisture buildup at the coldest part. I am not sure how factual this was, since after hearing this I adjusted the fridge so the doors were always closing themselves thanks to gravity, and the ice still kept building up. I did not replace the seal though :)

d_sem 1y ago

So can we project from the authors data that, under normal operation, both bridges roughly consume the same amount of power?

userbinator 1y ago

Agree with the others here that this is absolutely not a fair comparison. Most likely the door of the old one was not sealing well, hence the continuous running and frost buildup. I have a late 30s Frigidaire that I restored a few years ago which has been taking around 200kWh/y (70W compressor, ~33% duty cycle.)

koolba 1y ago
> I have a late 30s Frigidaire that I restored a few years ago Did I read that right with 30s, as in 1930s?
- userbinator 1y ago
  Not sure of the exact year, but it should be around 1936-1940.
mmooss 1y ago
> not a fair comparison. Most likely the door of the old one was not sealing well, hence the continuous running and frost buildup That's an expected cost of old fridges, so I don't know that it's unfair. A major reason old machines are less efficient is accumulated defects (people too!). If I said comparing a new car's fuel efficiency to my old one was unfair, because my old one has a lot of problems, you might say that's very fair.
- chii 1y ago
  it depends on why and exact purpose of said comparison. If the comparison is meant to show the drop in efficiency as part of age and usage, then yes. However, if you wanted to _only_ compare design upgrades, you don't want wear and tear to confound the results.
  - tonyhart7 1y ago
    but you cant compare only design ???? there is no one selling an 30 year old fridge "new"

bfkwlfkjf 1y ago

Anybody know how the author collected the energy consumption data?

ranger207 1y ago
From a link in TFA: https://ounapuu.ee/posts/2024/05/02/smartplugs/ https://ounapuu.ee/posts/2024/05/02/smartplugs/
- bfkwlfkjf 1y ago
  Thank you for the link. May I ask what TFA means though?
  - janfoeh 1y ago
    It is a commonly used abbreviation for "the f...ine article". On discussion sites of the Internet of yore, people would tell you to RTFA — "read the fucking article" — when it appeared you were chiming in without having first read the item under discussion. This is an extraction from that.

codedokode 1y ago

Electricity is so cheap (8-9 cents per kWh), it doesn't even make sense to invest in saving it. I would any day choose a cheaper product over 20% more expensive one that uses 10% less power.

russelg 1y ago
And if you didn't live in a place where it's cheap?
- codedokode 1y ago
  Then one need to do the calculations and decide based on that. One should also remember that the product might break so if it repays it cost over many years, there is a chance it breaks long before that. However, LED light bulbs are worth buying, the cheap ones (less than $3) repay their price in several months even with our electricity pricing.
foofoo12 1y ago
Electricity prices varies a LOT depending where in the world you are: https://worldpopulationreview.com/country-rankings/cost-of-electricity-by-country https://worldpopulationreview.com/country-rankings/cost-of-e...
- codedokode 1y ago
  I wonder why it is so expensive (46 cents) in Italy when other EU countries have lower prices. Taxes? Monopoly? Corruption? And why China has cheap electricity? They don't have much oil. Could it be that electricity price is based not on real expenses, but simply on "how much they can pay" principle? Anyway, Western Europe stands out as a dark spot on mostly light-colored map.
  - jansper39 1y ago
    There are huge differences between generation types, infrastructure requirements, regulatory environments, subsidies and ownership of electrical generation and supply equipment's before you even get into conspiratorial thinking. Globally, most electricity is not generated via oil anyway. China has cheap energy in part because they have a planned economy and a large usage of cheap energy sources such as solar and coal.

calmbonsai 1y ago

Well, um, yeah. If you're comparing anything to crap it will be better than...crap.

senectus1 1y ago

years ago we were renting a property that came with a fridge.. and our electricity bills where huge. I turned it off and our power bills more than halved. It was enough for us to buy a new fridge and barely notice the powerbills change after that

nakamoto_damacy 1y ago

Nobody talking about the refrigerators in Europe. They work differently. The ice forms inside the fridge part not just the freezer part. I don't know why and have not looked into it but it is in every fridge, including brand new ones.

jeroenhd 1y ago
Ice forming inside of the fridge is a result of moisture making its way into the fridge and staying in contact with the cooling elements. The cause can be a lot of things, from broken drain pipes to damaged door seals. A well-functioning fridge shouldn't have (much) ice buildup unless you live in a hot and humid area. Some modern fridges (usually the luxury models) also have features to defrost themselves if they detect that there may be frost buildup, but many fridges still have you do it manually.

rpcope1 1y ago

One thing that catches my eye here is the use of a smart plug on the refrigerator for current monitoring. I've tried a ton of different ones including the "good" ones like Shelly, and they all seem to use shunt resistors to gauge power draw. It would make me really nervous to use something like that to measure power draw on a big inductive load like a fridge. It's a shame, I've never seen a current clamp in plug form with no on/off switch, so you've basically gotta do some fab work, but that's basically really the only safe way to collect current data for anything that pulls a non-trivial amount of power.

thekoma 1y ago
Can you elaborate a bit further on what you’d need to do and why? It’s been a while since my electrical courses. I’ve been trying to measure home power consumption with these plugs (and the ones from IKEA) but I’ve been getting suspicious readings for inductive loads.
- jeroenhd 1y ago
  The IKEA plugs have a tidbit in the manual that says a "motor load" is limited to 300W while a resistive load can reach the full 3680W (at 230V, probably less if you're in a lower voltage country). Should be fine for modern fridges but older fridges may overwhelm the circuitry.
- rpcope1 1y ago
  I wouldn't bother using a smart plug. The other thing that's real dangerous about them that I didn't really elaborate on is the relay. There's a reason on something like a pump, fridge, AC unit, etc. you'd see a real contactor instead of a relay, and it's because relays are inappropriate and have dangerous failure modes for big loads like that and are typically way too small. In most real non-resi situations, you'd probably isolate the hot leg and put a good CT (current clamp) on it and read that. The great thing about that is you haven't added anything in the power path for the device, like a shunt which is what most smart plugs use. Current clamps are good for a lot more current (though I guess a proper shunt could do it too). The easiest way to do this in your setting is to find a good UL-listed electrical box with cable glands, a short piece of DIN rail, a male and female plug pigtail, some proper THHN wire and wirenets and a Shelly 50A EM Pro, and just graft the EM Pro into the box and wire it up with it's CT. You've now got something signficantly more durable and probably safer (and correctly specced for the load). I've done other things like using an HV Labjack and some good CTs or other one or few off designs. There's lots of stuff in the commercial/industrial space that does this well but it tends to be $$$. Again, for the sake of my own family, I wouldn't use non-UL stuff (most plugs and things that go in gangboxes that are "smart" aren't UL listed, and MAYBE are ETL) as you who knows how much or how well it's tested.

johnnyApplePRNG 1y ago

>assuming that it doesn’t break down. Ha! Good luck with that. The last time I bought a brand new freezer... it died in under 5 years... can't remember the brand... some asian import to Canada here. I went out and bought a used kenmore I think it was off of Marketplace... >15 years old and it lasted longer than the brand new one did... at 1/4 the price! These were both chest freezers and besides it's compressor being slightly louder, I doubt it used much more energy at all. If anything, it was probably insulated better, and used less I would imagine. It was much heavier, at least.

casey2 1y ago

If you have to buy 5+ refrigerators in the time the old one you are likely doing more harm to the environment than marginally more electricity consumption