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Comment by 383toast | Hacker News Reader

summary:

The creator argues that most dishwashers are designed to use a pre-wash dose and a main wash dose of detergent, a fundamental often ignored by single-dose pods, and presents independent ASTM testing confirming the new powder matches or exceeds the performance of a leading premium pod. The video also features a detailed demonstration using temperature logging and peanut butter to stress the importance of purging cold water from the hot water supply line before running a dishwasher, particularly in North America, to ensure the water reaches the optimal enzymatic temperature needed for effective cleaning. This is further reinforced by showing how adding pre-wash detergent dramatically improves the initial cleaning phase, especially with fats and oils.

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This has been his stance for a long time. He has a lot of dishwasher videos for some reason!

One thing I can't get a good answer to is whether the "prewash" step is universally the case or not. I have a good Bosch dishwasher and there's no compartment for a bit of pre-wash detergent. I don't even know if my dishwasher cycle has a pre-wash step. I would assume the dishwasher manufacturer knows what's best.

The owner's manual gives advice about not pre-rinsing the dishes because the food bits actually help the wash cycle, so I'm wondering if it works differently from the two-step process in this video.

Pods have become so ubiquitous that many companies ditched that powder compartment altogether. But you don't need one anyways just pour it into the cabin.

The video explains why there always is a pre-wash step. Regardless of whether it comes with a pre-wash-powder compartment or not. I will try his solution.

it's inverted. the closing soap compartment is the washing step, the pre-wash tray contents can just be dumped.

I have installed several dishwashers for friends and find them fascinating. All of the ones I have seen basically dumped the contents of the closing soap compartmens as soon as it started washing. Some dishwashers (looking at bosch) even have a little tray in the upper drawer that catches the pod.

It depends on the cycle for some. Mine one doesn't do a prewash for the 45mins QUICK cycle. But the ECO cycle does follow the normal prewash-then-wash process as described in the video. Hence I normally use the ECO cycle and put the correct amount of powder in both components. However in a hurry I sometimes just use the QUICK cycle and only use the main component as I know there is no point in adding more. The manual explained all this.

I'm fascinated at the number of people on an ostensibly techincal website who don't learn how their equipment works. You've summed up in a few sentences exactly how mine works, but there are dozens of commenters in this thread who appear to be unaware of the basic funcationality of their dishwasher.

All I would add to what you've said is that when my Bosch does include a pre-wash in a cycle, it checks how dirty the water is and only drains the pre-wash water if is dirty. If the dishes haven't caused the water to become dirty, it keeps the same water for the main wash cycle.

Also, I want to expand upon my first paragraph a little: I'm not having a dig at anyone who doesn't understand their dishwasher. I am just venting/observing that the world is filled with all kinds of different people and reminding myself that I shouldn't make assumptions about people as often as I do.

I've had this realisation many times, but it doesn't hurt to have it again. Communicating with people is lot quicker and easier when I remember that.

Yeah, I think there's some interesting related trends involved to. I still feel inclined with every new appliance to read the full manual, but I know not everyone has that kind of time or attention, especially if "I can just watch a YouTube video of it" is an option.

On the other side, you see appliance companies responding to that and shrinking their manuals of useful content because they assume you might just go watch YouTube videos instead. Some of the better ones might even include a QR code or 3 to officially produced YouTube videos, though so far that still seems rare.

Even in this video is the surprise reveal that something that used to be very common in manuals, full cycle timing diagrams, was "hidden" on a data sheet attached inside the door itself. Admittedly, it's great in that case to know that should that model be taken to repair that a repair shop might find that data sheet easily without having to search manufacturers' websites, but on the other hand some of those diagrams would be quite useful to me if I was the user of that machine.

sometimes even the company that made equipment doesn't know how it works.

my dishwasher after few months suddenly instead of filling water and starting wash cycle initiated some kind of fill & drain cycle that went for a while without going into wash mode.

i called in service. they replaced pump, solenoid. talked with manufacturer directly, swapped a couple of main boards. it made dishwasher snap out of it.

few months later it started again. this time i allowed it to do whatever it was doing. after 15 minutes it started to wash.

over the time i noticed that dishwasher does this water cycling every few months and adds extra time to estimated program duration.

about once a year after asking a few questions if sprayer hands/filters/etc are clean, it will add 2 hours to wash cycle.

none of it described in manual, manufacturer service personal and "Factory support" that service talk to know about it (maybe they do by now. they didn't few years ago)

omg thank you. my dishwasher has a prewash compartment so it's fine, but my clothes washer has a prewash step but no prewash detergent place. this elegant solution never occurred to me

video can explain anything, but reality is different.

my dishwasher manual breaks down each program. pre-wash exists only in half of programs

his dishwasher detergent videos are a good example of an "improved" product being more expensive and less effective (like disposable razors).

With better understanding you can achieve far better results. I no longer rinse or even scrape dishes. with the right approach my dishwasher performance has been stellar. The user manual also includes proper tuning to local water hardness levels.

Poor dishwashing also discourages people from cooking at home, which leads to less healthful diets. So it's an important thing to get right.

Dishwashing is fascinating.

I find his videos to have quite a bit of hand waving and poor methodology together with being overly verbose.

For example, he kept on saying that pods are not better in previous videos, but in the study he presented in this video, it showed that pods are performing significantly better than powders in every category. The study (which was not linked and I couldn't find it) was sponsored by a powder maker which the video recommends, but even this study showed just on par results with pods.

Nobody expects better results from a higher-priced product!

That has not been my experience with pods. When we switched back to powder the difference was night and day. Even my husband who used to swear by pods eventually gave in and agreed powder is much better. It is a bit fiddly yes but powder getting 99.9% of our dishes getting cleaned on the first run sealed the deal for us -- previously we were always having to add dishes to the next run or falling back to doing it manually. What makes it even more intersting is that even the cheapest powder beats every brand of pods etc we've tried. And we have a shitty cheap dishwasher that came standard with our new build house.

Generic $5 walmart powder is the best and is constantly sold out . I buy 2-3 boxes whenever I can

He does mention that a number of manufacturers aren’t making powders at all anymore, and also suspects out loud that they just aren’t trying with their powder detergents anymore, or are not bothering to apply improvements to their formulae to the powder form because manufacturers would rather sell the powders anyway.

He also specifically calls out Great Value brand powder as one he finds to be consistently on par with pod performance

He said a lot of things that are not backed up by the study he shared but didn't link, where powders clearly underperform pods.

At the end of the day, it'd have been much better for this community if we could have just gained access to a proper study comparing different cleaning options and learn from it instead of watching a 40 minutes video that doesn't say much and doesn't link to the study which is briefly mentioned there.

I agree with that

Perhaps there is an indentation on the outside of the detergent dispenser where you are meant to pour a bit of detergent for the pre-wash.

Like in the video: https://youtu.be/DAX2_mPr9W8?si=Njn749InqNCbjhQd&t=822

Nope, Bosch 800 series specifically do not have an indentation, and also state in their manual that they do not require any prewash detergent and the prewash does not run with any detergent.

Find a PDF manual for your dishwasher. It generally will describe if it has a prewash.

What your manual says is common to most dishwashers.

You can tell if your dishwasher has a pre-wash cycle if it does a short run, then you hear it draining, and then it does a longer full run. I expect it probably does.

Also, you can always add a bit of detergent to the main compartment of the dishwasher for prewash. The normal detergent compartment has a lid so the the detergent stays dry until the main wash cycle, and most prewash compartments are just an open tray.

Come to think of it, if there is a latching door on the detergent tray, your dishwasher definitely has a prewash cycle, or else they’d skip the door entirely

> Come to think of it, if there is a latching door on the detergent tray, your dishwasher definitely has a prewash cycle, or else they’d skip the door entirely

Alec also mentions this briefly in the linked video; if manufacturers could avoid the cost of a latching mechanism, they absolutely would. Its presence means a pre-wash cycle exists.

The default program on my Miele pops the door open like 2 minutes into the cycle. Maybe the slower ones don't?

My GE seems to skip the prewash cycle on the default setting for whatever reason. It does use a prewash on its "heavy duty" cycle though. Incidentally "heavy duty" also works infinitely better, with no more damage done to my dishes. YMMV of course.

That sounds like the behavior of the Eco program, which is often the default.

I have a Miele dishwasher. Not only is there no place to put prewash powder, but I can hear the little door for the detergent pop open like 2 minutes into the cycle when on the default program.

This dishwasher also came with a box of Miele pods (and they encourage you to buy more). I think it's designed first and foremost to not use powder.

>This dishwasher also came with a box of Miele pods (and they encourage you to buy more).

This is because the profit margin on them is much, much fatter. Miele still makes powder if you want to use theirs.

I have a Bosch as well, i sprinkle a bit of powder on the door. It has a pre-wash run which goes quick.

The manual is likely referring to not hand rinsing dishes before loading them which was very common 30 or 40 years ago. I had to train my Mother to stop doing that.

I still rinse dishes because it keeps the trap from getting absolutely filthy in one load.

> I still rinse dishes

This! I mean, at least get all of the low-hanging fruit with a quick, needle-spray pass of hot water. And to do so while the plates are still fresh so that stuff hasn’t had the time to dry.

Like, we’re talking about powering through table settings for a half-dozen people at a family dinner in less than 60 seconds. Plates, bowls, cups, silverware; everything done in about 10s per person. This isn’t any kind of a deep scrub; it’s removing everything that will come off easily as fast and expediently as possible before the dishes go into the washer.

The owners manual for my Bosch 500 says prewash detergent is not necessary. But it does have a prewash cycle as I can hear it draining before the main wash.

Note: This dishwasher provides the optimum cleaning performance without the use of a prewash detergent and further enhances our standards of sustainability and efficiency.

I keep my Bosch set to Auto and Extra Dry and use Kirkland pods. Rarely do I have anything that comes out less than perfect.

The Extra Dry setting seems to help with getting the glass and ceramics dryer. Plastics still come out quite wet since it uses a hotter final rinse rather than a heating element to get dishes “dryer”.

I have a previous generation Bosch 500 series dishwasher. For my use case I get the best results with the heavy cycle. However I found that adding loose detergent in there for the "prewash" resulted in soapy residue being left on the dishes if used in conjunction with the heavy cycle (but not with the normal and auto cycles).

Alec's dishwasher videos are based on some rather primitive dishwashers. For instance he talks about his test unit not flushing out the spray arms, but Bosch/Siemens filters the water going to the spray arms so it wouldn't recirculate dirty water anyways. Same deal with the prewash. Bosch uses a turbidity sensor to determine how many "prewash" cycles to run and when to reuse the water, something his test unit very clearly does not.

Yeah, I think one has to understand the man to really get something useful of what he says. He is kind of a cheap man and much of what he says really applies to low-end devices. Some expensive devices may have similar problems to the cheaper stuff but really if you buy a premium device you won't have many of the problem he talk about.

I know this type of person very well. They always have some reductionist approach to things, where for them, the expensive stuff is mostly marketing with added bells-and-whistles and largely works the same. My experience is that this isn't quite right. Some brands do have a premium that is more related to style/status but if you buy some seriously engineered stuff it will work much better most of the time.

He's a midwesterner so some of that's to be expected. But AFAIK KitchenAid is one of the higher end Whirlpool brands. I just checked the orange big box store and the price difference between the KitchenAid dishwasher lineup and that of the Bosch 300/500 series comes down to what's currently on sale.

For reference I'm pretty cheap too but try to be pragmatic. My fridge is a $600 Frigidaire (AEG/Electrolux) top freezer unit. The main selling point was that another youtuber (an appliance repair guy by trade) pointed out that it still has a mechanical timer. They get mocked by appliance sales droids but the top freezer design is significantly more efficient than the alternatives and the lack of electronics mean that you're more likely to be able to repair it.

I don't know enough about US states subculture to infer that, it's just the opinion I formed watching him.

I agree that KitechnAid is more on the higher-end side, he even said himself that it's kind of a premium device. It doesn't surprise me, because at some point in your life you want to stop with the frugality shenanigans and just want stuff to work if you can afford them.

To be clear that's not a critic, I tend to be as cheap as can be reasonable as well, it's generally a decent way to proceed, to avoid overpaying for useless over-marketed, over-engineered stuff. I'm just trying to give some context but I think we are in agreement anyway and I do believe anyone who watches him long enough will get the gist of it at some point.

> He has a lot of dishwasher videos for some reason!

have you watched his videos? dude is on the spectrum.

to be clear, he makes good vids. but his fascinations exist for a reason.

it doesnt feel nice to try to dismiss someone's interests and hobbies as "they're autistic"

It always seems a shame when naturally clever people are assumed to have autism, or when their cleverness is attributed to it. Why can't someone just be intelligent without labels?

Reductive and inaccurate.

> He has a lot of dishwasher videos for some reason!

He is known as Angry Dishwasher Man for a reason.

If the detergent container has a door, then that means the soap is dispensed later, which means there is a pre-wash stage it’s trying not to waste the detergent on.

Thanks for the summary.

American dishwashers don't have their own heater? All dishwashers I've seen in Australia only have cold water supply.

They do, but they are generally confined to 10 amps, so they do not heat quickly.

American dishwashers are typically hooked up to hot water. Some will have heaters but they're not that powerful and they may only run for the main wash cycle

Not true. Dishwashers get cold very often.

...what's not true? I can't tell what you're disagreeing with.

American dishwashers are always hooked up to the hot water supply. It’s right in the installation manual, and I’ve never seen one that wasn’t.

They do. I didn't realize this until my natural gas supply company decided to replace my meter on a Friday. Without alerting me ahead of time so that I could, you know, plan to be gone while my house had no hot water.

Whenever natural gas supply is turned off in the US, for any reason, only the gas company can turn it back on. And they can't do so if there's a leak at all. You have to call a plumber to come out, detect the leaks, and fix them. After that, you can call the gas company to come back out (but not on a weekend) to turn it back on. And a same-day request for service requires someone to be home ALL DAY after it's called in.

And this is how I ended up showering at work for three days that week after not having had one over the weekend.

As an American expat, I will use this story to explain some of the indignities of living in America. Thank you for sharing.

Every country I have ever discussed with its residents has something that, on its face, is a reasonable safety precaution (I definitely don’t want to blow up my house), but in practice is just a way to make your life miserable while helping the people who work there have an easier day.

This just happens to be the one that affected me. Like modern gas water heaters that have electric ignition instead of pilot lights, because the one serious reason to have gas water heaters is that they work when there is no electricity. Now it’s just a price distinction.

My parents used to have an old cooker which rather than having a spark button, had individual pilot lights for all of the hob burners and the grill. My mother was forever worried about whether one of the damn things had gone out (which they occasionally did). I think if you switched the supply off, switched it on again, and someone has left their house for a week, it might build up a significant amount of gas. Although they are supposed to be small enough not to. Presumably there were hardly any of those left now, but they can't assume they're all gone.

Pilot lights are often designed so that the heat from the flame holds a bimetallic switch in the open position. Should the light go out, the bimetallic switch will shut as it cools.

For water heaters and wall furnaces with a gas control valve, yes. For old stoves, they don't.

TBF the amount of gas used in old style pilots is really tiny. I’m sure it’s possible to accumulate dangerous quantities somehow, perhaps in a sealed subterranean basement if using propane instead of natural gas.

Natural gas is mostly methane, which is lighter than air and easily escapes most structures.

Yes it's not a concern for kitchen stoves. The amount of gas/flow rate is too low.

Natural gas today is mostly methane, but in the past it often had large concentrations of CO. In 1950 you can turn the gas on and stick your head in the oven as a form of suicide - won't work anymore (unless you get the house to explode).

Fascinating. I double-checked with ChatGPT (FWIW), and it confirmed. It said that currently, natural gas is extracted and shipped in its mostly pure form. In the mid-20th century, natural gas was "town gas," manufactured by heating Cole in the absence of oxygen. That produced a lot of carbon monoxide.

That is an insane solution to the problem. I’d rather put a match to it.

Sorry how is this story relevant?

> Whenever natural gas supply is turned off in the US, for any reason, only the gas company can turn it back on

Doesn't match my experience. My colleagues and I are able to turn on or off the gas supply to our houses at will.

often around here in texas, when the gas is turned off due to an issue, the gas company disables the meter, or even removes or bypasses it. And I live in gas land, where we have natural gas piped in to the kitchen, bathrooms, laundry, outside for grills, as well as the furnace. We've seen it a lot, if you call the gas company about smelling gas, they come and remove your gas meter until you hire a plumber to go find the leak.

What needs gas in the bathroom?!

You’ve never made s’mores while doing a #2?

Depending on the age of the house, it might have a gas-powered radiant heater in there. The one I grew up in did (built late 1930s).

> And this is how I ended up showering at work for three days that week after not having had one over the weekend.

I discovered the unexpected value of a YMCA membership when my hot water was offline for a while.

>Whenever natural gas supply is turned off in the US, for any reason, only the gas company can turn it back on

I had a seismic shutoff installed at my gas meter and the plumber who installed it had no problem turning off the gas and turning it back on when he was done. (and then turning it off again to demonstrate to me how it worked).

He re-lit the water heater pilot light before he left. The gas company was not involved at all.

A dishwasher cycle is usually only going to run for a specific period of time. Its more effective it if starts that time closer to the proper temperature rather than relying on waiting for the heater to get the temperature up to that time. Especially on the pre-rinse cycle, where the heater may or (probably) many not engage.

American dishwashers don't have their own heater?

Some do, some don't.

The ones that do vary in ability by overall dishwasher quality.

The ones that don't are hooked up to the kitchen's hot water line.

This is considered more energy efficient because a home's hot water heater (whether electric, gas, or another fuel) is better at heating the water in a bulk capacity than a tiny heater in the dishwasher.

The downside is that the cold water between the big water heater and the dishwasher has to be purged first for it to be really effective. If your hot water heater is in the other side of the wall, no problem. If it's six rooms away, problem.

Hot water from the house supply isn't that hot though? My dishwasher gets MUCH hotter than the hot water supply... and I don't think the heater is "tiny" I think it's a rather substantial element. The dishwasher also doesn't need to heat up a "bulk" amount of water, just the amount of water used for washing the current load of dishes.

Hot water from the house supply isn't that hot though?

Depends on how you have it set. My current and previous hot water heaters had thermostats which permitted adjusting the temperature.

They also had warning labels on them about scalding water. If it's hot enough to scald, it's hot enough.

The dishwasher also doesn't need to heat up a "bulk" amount of water, just the amount of water used for washing the current load of dishes.

If you're washing dishes and someone is, or has recently, taken a shower; or someone is, or has recently, done laundry; or someone is, or has recently shaved or done any of the other dozen things that draw from the hot water heater, then the water is already hot and available and doesn't need to be heated all the way from cold by the dishwasher. A properly insulated hot water heater can retain heat for quite some time.

My cheap GE dishwasher uses a hot water line, but also has an internal heating element to "boost" it, and help dry. My electric bill definitely suffers if cold water is used.

Watch the video; it makes a huge difference even though the hot water input is not as hot as the water can get when the dishwasher runs its heating element.

Also the size of the heating element is irrelevant. What matters is the power dissipated. Most dishwashers in the US will use only about 900 watts of power even when plugged into a circuit that supports 1500 watts. In the EU they often hit 3000 watts. Even when just heating up a gallon or two of water that makes a huge difference.

Modern dishwashers, especially in Europe, are using heat pumps as well. They don’t really benefit from the extra voltage and watts anymore.

Sure, but most people don’t have a modern dishwasher. It’s an appliance that lasts 20 to 30 years ergo most people have old dishwashers that were manufactured decades ago.

Ya, but eventually the new tech will take over and we will be talking about very different things. Even if you just consider new builds, or hundreds of millions of Chinese buying their first dishwasher ever. Also, lots of utility districts offer incentives to upgrade to more efficient appliances.

I think you’re confused, heat pump dishwashers are extremely rare even in Europe, and basically unavailable in the U.S.

That’s not true at all. Bosch is mostly heat pumps, and they are a top consumer brand in both the USA and Europe.

it looks like "heat pump" in bosch dishwashers is a pump that has usual heating element inside it. https://www.bosch-home.com/us/en/product/12019637

Bosch dishwashers are NOT heat pump dishwashers! They have a pump that also heats the water. They call it a “heat pump” but I find that terminology a bit strange, as its clearly not a heat pump (which is a term of art in appliances and HVAC). It’s just a resistive heater that is no more efficient than any other dishwasher heating element.

Crystal dry uses a heat exchanger for drying, so I guess that is what they are referring to. I guess you could try to claim that only the way HVAC's move heat around qualifies for being called a heat pump, not any other way of moving it should count right?

Here is what I got from Gemini:

Bosch does not refer to their dishwashers as having a "heat pump" in the same way the term is used for HVAC systems; rather, the part is often called a circulation motor and heating assembly or a combined "heater/pump" unit by users and repair sites. Bosch dishwashers use a flow-through water heater (a type of resistive element) to heat the water and a different, non-refrigerant-based system for drying. How the Bosch System Works

Water Heating: All Bosch dishwashers use a flow-through water heater, which is a heating element integrated with the circulation pump. This system rapidly increases the water temperature to the required level. It uses electrical resistance, not the reverse-refrigeration cycle of a true heat pump.

Drying: Bosch dishwashers (especially the higher-end models with features like CrystalDry) typically do not use a separate heating element for drying. Instead, they rely on a process involving a stainless steel tub and a heat exchanger or a mineral-based drying technology (like Zeolith for CrystalDry) to condense moisture and wick it away from the dishes. This is an energy-efficient method of moisture removal, not active heat generation for drying.

CrystalDry is an “upsell” feature on the high end versions of their dishwashers for more efficient drying. It’s not the thing that they’re calling a heat pump, that’s the water pump that also does resistive heating. Bottom line is, Bosch (nor anyone else afaik) does not make dishwashers that are more efficient due to using “heat pump” technology.

> I guess you could try to claim that only the way HVAC's move heat around qualifies for being called a heat pump, not any other way of moving it should count right?

Anything that moves heat from one area to another, not just evening them out but actually forcing the heat to move, counts as a heat pump. HVAC style, or peltier style, or other methods with tension or chemical reactions all count.

A combination heater and circulator does not do that. It is not a heat pump.

Also, I’m way too lazy to look it up right now, but I’m quite certain I’ve heard of dishwashers that run the hot water for a little bit before letting it fill the basin. Like, I’m pretty sure this sort of thing is commonplace.

It’s not like the engineers for heaterless dishwashers are just too stupid to realize there’s an obvious workaround for having to purge the line before filling the basin. Especially when the performance is so much measurably better when you do it.

Like I said though, it’s a guess. It’s also possible efficiency certifications ding you for the excess water use.

Most of the new ones (at least higher end ones?) have heat pumps that heat water and handle drying. They are efficient enough to work on 110V, and the trade off is longer cycle times. Bonus: no more plastic utensils melting because they fell to the bottom resistive heating elements.

Same in NZ, never seen a dishwasher with a hot water connection.

If you check the manual you might find that you can hook the single inlet pipe up to the hot water tap.

I feel like it's probably pointless. The dishwasher will be full of water before the hot water starts coming out the pipe. Depending on how far the dishwasher is from the water heater I guess.

https://en.wikipedia.org/wiki/Circulator_pump#Use_with_domes...

This seems like something that only makes sense when water is scarce but electricity is cheap. You’d be constantly losing heat to the poorly insulated pipes.

I have all hot water pipes insulated in my house

People who do it more or less don't care about the price of energy (except maybe in the abstract).

It's for comfort and convenience.

And you're fully losing heat if you dump lukewarm water down the drain (instead of cycling it back to the heater) to eventually get hot water.

In most kitchens I've seen, the dishwasher is pretty close to the sink. In fact the sink and the dishwasher often share a shut-off valve. So if you run the water at the sink until it's hot, then start the dishwasher, it will get hot water.

Problem is, that most dishwashers have a prewash and a main wash. By the time the prewash is finished and the main wash starts, the water in the supply line will have cooled off quite a bit.

Not just the shut off. My dishwasher's drain hose goes up into the sink's drain plumbing much higher than I would have thought.

This almost made a mess when the sink was clogged and the dishwasher tried to pump the water out but had nowhere to go.

You can install airgap for this. In usa building code mandates it on multiple states

Is that the point of the air gap? I can't even get a straight answer from plumbers on what it's for. I don't see how that could possibly help with a clogged drain, just seems like a secondary point for the drain water to come out.

I'm fairly sure the point of air gaps on drainage is to prevent sewerage water from backing up in to appliances if the sewerage line is blocked. It will instead spill on the floor where it will be more easily noticed and cleaned.

That’s exactly what it’s for. If you block the sink drain and fill it with water, you can have water flow down the dishwasher drain hose and into the sump in the dishwasher. If that happens during the rinse cycle you’re rinsing with grey water.

That is exactly why they are required in restaurants. You wouldn’t want the sewage to back up into a sink where food or dishes might be.

Pumped out water has to go somewhere . With the airgap, it will either back out your garbage disposal or pour out your airgap into the sink basin, depending on the location of the blockage.

The airgap causes the pump to be physically incapable of backfeeding the drinking water supply with dishwasher waste

iirc its less about contaminating drinking water (there is a valve and pump to get through. rather tricky) and more about waste getting into dishwasher during cycle and you getting contaminated dishes.

my wife once decided to dump into garbage disposal a bunch of uncooked broccoli at once. it clogged garbage disposal and drain. when i tried to unclog it with plunger it backed into dishwasher (was hooked directly to garbage disposal bypassing airgap). took me hour to get everything out of dishwasher.

You should actually watch the video so that you can see the graphs; it’s not pointless.

I don't think the dishwasher will be "full of water" as it doesn't actually fill up - rather, it only uses 2 gallons maximum per cycle, about the amount that would be the bottom of basin of the washer.

That's what I meant. The water drawn from the dishwasher is small enough to not even purge the cold water from the line in many houses. So you would just be wasting heat by filling the pipe with hot water while only taking the cold water from it.

When I do the dishes I hand wash those that can't be put in the dishwasher before I start the dishwasher. This ensures that the water that goes into the dishwasher is already hot.

“16:12 The importance of purging cold water from the line”

Thus the video's advice (also in my dishwasher's manual) is to run the water from a nearby sink until it's hot before starting the dishwasher. Because it helps significantly to get hot water at the input when US dishwashers are limited to 1200W of heating.

The video explains that dishwashers sold in 110V countries often has a hot water connection as it's too slow heating water off a 110V/10A circuit so it is more efficent to utilise the hot water pipes. However we live in NZ, a 230V country so we get dishwashers that can heat water from cold fine off a 230V/10A circuit so no need for a hot water connection.

Modern heat pump dishwashers will heat water on 110V just fine, but you are looking at 3 hour wash/dry times anyways. My Bosch isn’t connected to hot water and even has a sanitize mode.

Bosch dishwashers have something they call a “heat pump” that is a water pump that also heats the water with resistance heat. It’s not any more efficient than the normal heating coils in every other dishwasher, and it isn’t a “heat pump” that uses a refrigeration cycle (as one would use to e.g. heat their house).

Heat exchangers are used for drying, they don't have heating coils for drying.

We’re talking about heating the water, not drying. The discussion started with regards to energy used to heat water vs. using water from the hot water tap.

Some US washers don't but many do. However, US washers tend to not heat water as quickly or to as high of a temp. The video cites two reasons: 1. US power being 110V vs 220v. 2. US dishwasher heating elements being limited to 800 or 1000 watts because many are designed to potentially share one 20A residential circuit with an oven and/or fridge due to possibly being retrofitted into a kitchen built before built-in dishwashers were standard and manufacturers not wanting to create different models for retrofit vs new installs.

3) manufacturers placing energy star improvement quotas over safety in programming the cycles.

The energy star stuff isn't unique to US dishwashers though.

> share one 20A residential circuit

15, dishwasher manufacturers can't assume the dishwasher is on a 20.

This plus the comment about sharing a circuit with an oven. If the oven is electric, even in the US it is 220v. If it is gas only, then it could be 120v as it only needs to run the igniter and other circuitry without running any heating elements.

I think he said sharing a circuit with a fridge, which are generally 110 in the US -- i think this is how my apartment is wired (2-phase 30A to oven dedicated, one 20A for the whole rest of kitchen)

Trying to run a resistive heater on the same circuit as a fridge compressor without tripping leans towards very conservative wattage

That's funny. Code in Ontario Canada is that the fridge needs to be on its own circuit. It's funny because we have an extra-big-ass inverter drive fridge that never draws more than an amp or two, even at startup because it's inherently soft-start.

Just a waste of copper and a beaker really.

>Just a waste of copper and a beaker really.

But also helps avoid the case where your coffee maker trips the breaker shared with your refrigerator and you don't notice until the food in the refrigerator is warm. (which was a risk in my previous apartment - the counter circuits were shared with the refrigerator). I think it makes sense to have it as a separate circuit.

Good point. I haven’t tripped a GFCI in a long while but I don’t actually know if my fridge will lose power when I do trip the GFCI. My guess is that it will since it does have a water line and ice dispenser so probably requires being wired into the same circuit.

> counter circuits were shared with the refrigerator

Ouch. Code here (Ontario) is that not only does the fridge need a separate circuit, but counter outlets need two separate circuits: each socket on the duplex outlet is required to be on a separate circuit (although multiple outlets can all share the same two circuits, but you're supposed to alternate top and bottom).

Of course, if your home is older than I am or it's a handyman special, all bets are off. If I run the microwave while someone is vacuuming in another part of the house it'll trip the breaker.

My thought was to share it with the lights, so you get an early indication if/when there is a fault than just your fridge going out.

> But also helps avoid the case where your coffee maker trips the breaker shared with your refrigerator and you don't notice until the food in the refrigerator is warm.

Didn’t notice the coffee was cold?

Overall, given the massive fears of a fridge failure, which can happen beyond just electrical failures, very very very few people have any kind of monitoring/alarming for this event. You’d think that would be the first requirement.

Refrigerators have become incredibly efficient in the last 40 years. I mean incredibly.

It sounds like this law is outdated.

Electric ovens in the US have required dedicated 40 or 50 amp circuits for decades per the NEC. Dishwashers, as well, have required dedicated circuits for a while but the 20 amp requirement is a more recent development (although it's probably been at least a couple decades).

Kitchens in general have required 20 amp general purpose circuits since at least the early 80s. However the NEC (but not the Canadian equivalent) allows for 15 amp duplex receptacles on 20 amp circuits so home builders looking to save a few pennies often use those. Besides, there are few if any, residential appliances out there that have NEMA 5-20 plugs. Then again hardwiring dishwashers was pretty common up until recently.

in traditional times it was customary to buy a few outfits high quality clothing that would last, and wear the same clothes for a week at a time, and then really boil them clean. This is the European market.

post world war 2 consumer choice culture in the US led to people buying cheaper clothing but varying their outfits every day and cleaning them (with copious availability of water) with less intensity.

once these patterns are established in the market, they become more like customary and it's what consumers expect of their appliances, detergents, etc.

This has always struck me as dumb, as until recently it was far cheaper to use your existing (gas-fired) hot water than to use a resistive element. However, with gas going out of fashion (and already hugely expensive in the Eastern states), and abundant solar PV, the calculus has changed.

The problem is that the first few litres of the water coming from the hot water pipe may be cold or warm. Therefore adding a resistive element is a better solution to guarantee a specific temperature.

Gas (especially just in time) still works well for water heating even if you can use heat pumps for everything else. No sure when that will flip, I assume it will eventually.

Gas is already outlawed for new builds in Victoria, despite vast gas resources in the Bass Strait. Presumably that's the direction other states are heading too.

It was a direction some states in the USA were heading before Trump, but now… anyways there will come an economic/technological point where electricity just makes more sense like it does for almost everything else. No need to legislate a transition when one will happen naturally, but we aren’t there yet.

I can’t speak to Australian dishwashers, but trying to skip the video by catching a summary has failed you. Heating is discussed extensively in the video

traditionally (in household washing machine time) US houses were large and had a lot more hot water capacity for the whole house, and putting a heater into individual appliances was not necessary/cost effective.

retrofitting old traditional houses (especially stone) with higher capacity plumbing was expensive and infeasible, so putting heaters in appliances was a cope for markets that needed it.

Quite, another thing to add to the list of USAian weird exceptions.

My fairly cheap dishwasher in the UK has its own heater, but you can attach it to a hot water supply, which may save money as gas is so much cheaper than electricity.

I've micro-optimized my dishwasher setup to have all my 100+ pods and other in-bulk dishwashing-chemicals stored in a compartment between my two dishwashers.

I'm also firmly in the camp of having a flat cutlery compartment at the top and not that inefficient, and uncivilized, scarring, basket in bottom section.

Until seeing that video I thought I was crazy. I've found my master.

You have two dishwashers in one kitchen?

I recall reading, I think in a comment here long ago, of someone who did that. He had just enough items to fill one dishwasher. By having two he could use one for storage and one for cleaning, with the two alternating roles.

I.e., he started off with all his things clean and in dishwasher A. As he used things he pulled them from A and put them in B. When B is nearly full and A is nearly empty, run B, move any remaining items from A to B. Then B becomes the storage space and A becomes the place to put the dirty items.

Just in case one of them asks for a divorce

Yes, i do. The idea was that it keeps the kitchen cleaner, because there's no more gross kitchenware that didn't made it into the dishwasher. Always wanted that. Then saw it in practice at a startup once, and then finally gave it a go.

There will be instances when both are just full and you still end up visible filth, but even then, you at least have to go just once into clear-out mode. It works out great so far. If it didn't... well, I guess I'd need to buy a third one ;-)

I never understood the requirement for having to preheat your pipes. The dishwasher has access to a hotline, and a drain. Why wouldn’t it just run the hot water for 60 seconds to ensure it has maximum heat. This would just be a software feature, and cost nothing on their part.

It seems so arcane for the operator to have to do this before running a cycle

There are regulations on water usage for dishwashers. That purge would eat into its water usage.

Yes, purging the cold water manually does exactly the same thing. We live in a flawed world.

Interestingly the Gemini summary is nowhere near as good. But when it is... how helpful will that be! So many things with a very good summary will save so much time / avoid having to dive into unless truly in need of the details.

But the quality of the summary - and maybe the ability to expand it if slightly more details are required - and the low latency with that - are all super important. In that sense, AI can potentially save a lot of time in getting the right information quickly.

I summarise YT videos with Gemini all the time. You can easily control the length and depth of the summary & get it to focus on particular things etc, before investing time in watching it, only to find out it's promotional, superficial, clickbait, or some combination of all 3.

Good to know! Thanks.

Does Gemini really does a good job at detecting promotional video ? For example, that one video discussed in this post is one huge promotion for his friend product but it is actually built in a way that clearly appeals to nerdy audience. The video boasts the rigorous testing, provides scientific explanations, nerdy jokes, etc. What Gemini says about that ?

I don't directly ask it if the video is promotional, but you can usually get a sense from the way the summary is written.

i have miele dishwasher with detergent powder cartridge that allows dishwasher to dispense it at will. it never used during pre-wash cycle in any of the programs that dishwasher has.

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