[eru]

> Run your kitchen sink hot water a little before starting to get warmer water into the dishwasher

Note: this only makes sense in the US (or wherever else it's common for your dishwasher not to heat its own water).

> But don't put two pods in, i.e. one in the detergent tray, and another detergent pod into the tub because these pods are very concentrated and harsh and will damage plates. Only add a little extra powder

I'm not sure damaging your plates is the reason to avoid the extra pod. Plates are often made of some glass-like or ceramic-like material and not that easily damaged by chemicals.

[stdbrouw]

Don't know about the pods, but for a while we used DIY dishwashing powder with soda crystals as the main ingredient, and after a while you could definitely notice slight scratching of glassware, and any printing would fade pretty heavily. Not sure if that's a chemical process or simply the abrasiveness of the powder.

[eru]

Oh, dishwashers are definitely hard on printing on glasses.

I'm not sure about scratches. I can imagine you would get scratches if your detergent (especially crystals) doesn't completely dissolve? I mean, people even sometimes use sugar as a scrubbing agent. Dissolved sugar can't scratch anything, but sugar crystals can.

[maxerickson]

It's likely chemical.

https://www.maytag.com/blog/kitchen/how-to-prevent-etching-g...

[amiga386]

> > Run your kitchen sink hot water a little before starting to get warmer water into the dishwasher

> Note: this only makes sense in the US (or wherever else it's common for your dishwasher not to heat its own water).

I don't think this is a US-vs-world issue. Other countries' dishwashers are also connected to the hot water supply.

Rather, Technology Connections is suggesting a hack.

Your dishwasher, wherever in the world you may be, will start up by using whatever water it can get for an initial rinse of the dishes, and it will measure how dirty the water is after this initial rinse.

Normally this water will be tepid. But if you make it hot by running your hot tap first, the hot water will rinse more dirt off the dishes than tepid water, the dishwasher will detect more dirt, and so it will assume the dishes need more aggressive cleaning, and adjust its program accordingly.

[bakje]

> Your dishwasher, wherever in the world you may be, will start up by using whatever water it can get for an initial rinse of the dishes, and it will measure how dirty the water is after this initial rinse.

> Normally this water will be tepid. But if you make it hot by running your hot tap first, the hot water will rinse more dirt off the dishes than tepid water ...

I might be misunderstanding you, but this definitely doesn't apply everywhere.

I don't know how this works in the rest of the world, but in the Netherlands at least my dishwasher is only hooked up to the cold water, running my tap will have no effect on the temperature of the water my dishwasher receives.

[amiga386]

I can't speak for every person's experience, but what I believe is that most dishwashers being sold today, anywhere, are capable of being connected to domestic hot water, or cold water. They will work with both. That's not the same thing as saying every dishwasher being sold can do this, but check your instruction manual. Perhaps it can. As per a sibling comment, decide holistically if that would be a good idea or not.

Unless someone can point me to the existence of regulations saying something like "it's illegal to connect a dishwasher to a hot water line, it's gotta be cold water that the dishwasher heats up itself", then my expectation is that most dishwashers can be connected to either hot or cold, and will heat the water to the correct temperature.

Looking at EU regulations, as far as I can see, they don't regulate the intake temperatures that dishwashers have to accept. What they do regulate is energy usage labelling, and mandating there must be an "eco" mode, what the eco mode must do, and if you get to select multiple modes then "eco" mode must be the default. https://commission.europa.eu/energy-climate-change-environme...

[rlpb]

> I can't speak for every person's experience, but what I believe is that most dishwashers being sold today, anywhere, are capable of being connected to domestic hot water, or cold water. They will work with both.

This is not my experience. Nowadays appliances such as washing machines and dishwashers, in Europe at least, only have a cold water inlet.

Apparently modern appliances use so little water overall that it's no longer efficient to connect them to a hot water supply, since they will stop drawing water before the hot water runs through the pipes, and therefore it just wastes the hot water.

[jsmith99]

Many European machines accept hot water. Any Miele does, and my entry level Bosch (in UK) accepts up to 60C but you have to set some obscure setting on the machine (the manual explains). But I find even cheap machines wash pretty well even without this, and you are right about it it being hot only if the machine is right next to the boiler.

[Cthulhu_]

I bought a new dishwasher (and it's not as good as the old one :/), in the instruction manual it says you can use some configuration to tell it it's hooked up to hot water.

It makes sense to hook it up to a hot water line, given things like solar collectors and heat exchangers heating / pre-heating water.

[derda]

> Other countries' dishwashers are also connected to the hot water supply.

I think it is more a 110V vs. 230V household power issue. For 110V countries like the US the amps needed to heat up the water would be pretty high or the heat up would take very long. In Europe however I have yet to come across a dish-washer that is connected to the hot water supply.

[eru]

The US actually has 220V available in most households.

[sgerenser]

Yes, virtually all US households have 240V service. But virtually none of them have a 240V outlet where the dishwasher goes.

[olau]

Just a note on the hot water supply: Whether this happens depends on three factors:

- Does the dish washer support it? Not all do in the EU.

- Did the plumber install a warm outlet when they set up the connection for the dish washer?

- Does it even make sense from a holistic perspective?

The latter depends on the specific circumstances. For instance, I live in a country with district heating, and here it makes sense, because then I can use cheap heat. My dish washer supports it. But there's no warm outlet installed by the plumber, and currently the heat is mostly from coal, whereas the electricity is mostly renewable, so for the time being I just let it be.

[kuschku]

> Other countries' dishwashers are also connected to the hot water supply.

No? I'm in Germany, all dishwashers I've ever had were connected to cold water and heat their own water.

[amiga386]

That's OK, that's your choice. I believe most dishwashers will work with either.

My dishwasher is connected to a hot water tap and also heats its own water to exactly the correct temperature... it just doesn't need to heat it as much because it's connected to a hot water line.

Here's the install guide of a random dishwasher selling in Germany right now: https://media3.bosch-home.com/Documents/9000521334_L.pdf

It says to connect to a water source with these characteristics:

* Pressure: 0,05 - 1 MPa (0,5 - 10 bar) * Temperature: max 60°C

It doesn't specify a minimum temperature although I assume it'd have to be >=1°C. But it is clear you can connect to either a hot or a cold water line.

[kuschku]

Sure, it optionally supports it, but that's an extra water line that'd need to be run.

And what for? Whether the instant water heater or the dishwasher heats the water, it's still going to be the same amount of electricity, the same cost.

[ce4]

Have a look at the overview on Geizhals.de - Almost all current models have optional hot water intake nowadays (like 95%+ of the models from AEG/Bosch/Siemens/Neff/Bauknecht/Miele). This is to further advance the energy-rating. Doesnt apply to the cheaper manufacturers though.

981 of 1027 models from a number of well-known brands have an optional hot water intake: https://geizhals.de/?cat=hgeschirr60&xf=1069_AEG+Electrolux%...

[kuschku]

Whether you heat the water in the dishwasher or in an instant water heater, it's still going to be the same amount of electricity for the same cost.

I think in the US people might heat water with natural gas, which is cheaper, but that's not really the case in most rental apartments in Germany.

[Spare_account]

>I don't think this is a US-vs-world issue.

Which country are you in?

I'm in the UK and we only connect dishwashers to the cold supply. Other comments in this thread from NL and DE are the same.

[amiga386]

I'm in the UK and have a dishwasher connected to the hot water right now. There is not some country-wide uniform "we".

The manual makes clear this is quite OK.

They work with either hot or cold water. They will heat the water to the temperature they need. They don't work with _too hot_ water, hotter than they would heat it themselves (e.g. >60°C), but that's also outside the range of most domestic hot water supplies (which per BS 8558 should have a draw-off temperature of 50°C at sinks).

As a quick sample, here's the Argos dishwashers page: https://www.argos.co.uk/browse/appliances/dishwashers/c:2961...

Pick any dishwasher at random, go to Specifications -> General -> Water fill. Every single one I picked, all from different manufacturers, said "cold or hot"

Looking at one random choice's data sheet: https://documents.4rgos.it/v1/static/3425118_R_D010

> Maximum temperature for water intake (°C) 60

[nemetroid]

I wasn't able to find manufacturer recommendations from Argos, but I did find two Swedish manufacturers that support either hot or cold water, but recommend that you use the cold water line. One of them claims that detergents are designed to work better when starting with cold water (presumably this is not the case in the US, where hot-water-only machines are the norm).

> Connect the machine to cold water if possible. Then the dishwasher itself heats up the water during the washing phase and the final rinse, which means that you save about 20 percent of energy. Today's dishwasher detergent works best and tablets dissolve better when the program starts with cold water.

> Dishwashers connected to cold water use around 30 percent less energy than dishwashers connected to hot water. A dishwasher connected to cold water only uses hot water when it is really needed.

https://www.cylinda.se/produktguide/kok/diskmaskiner

https://www.electroluxhome.se/vitvaror/diskmaskin/inspiratio...

[jrsdav]

> Plates are often made of some glass-like or ceramic-like material and not that easily damaged by chemicals.

A ceramic is a glass (or the other way around), just of a different material composition. And yes, a dishwasher can easily damage both glassware and ceramic dishes depending on how the glass (or glaze, in the case of a ceramic dish) was formulated.

A common durability test for ceramic engineers is indeed — placing it in the dishwasher.

[squokko]

> this only makes sense in the US (or wherever else it's common for your dishwasher not to heat its own water).

American dishwashers heat their own water too - I think this is for cases when the dishwasher has a time limit on how long it will spend heating up the water (perhaps to meet expectations on cycle length).

[dwaite]

American dishwashers hook up to the hot water line, vs the cold water line in some other countries. They do have their own heaters, but household models are limited to 1200-1800 watts.

The pre-wash/pre-rinse cycle may only give enough time to raise the temperature 10-15 °F before the regular wash cycle starts. I do not believe they will delay the start of the wash cycle due to the water not yet being to target.

Starting with cold water reduces the effectiveness of the initial rinse, and may reduce effectiveness or prolong the wash cycle.

[interestica]

> Plates are often made of some glass-like or ceramic-like material and not that easily damaged by chemicals.

The edges/sides of my Corelle plates (a layered tempered glass) are rough due to the dishwasher. Also, those with prints have faded significantly.

[sgerenser]

Yeah this is a common problem with dishwashers and certain types of glass, it’s called “etching.”

[AuthorizedCust]

My US-sold, 2015-purchased Bosch dishwasher handles its own heating.

The first water cycle does not get heated, but all subsequent ones do. I’m tempted at switching it to the cold water line.

[Mandatum]

The initial rinse cycle never heats water. Running hot will help.

[traveler1]

Hot and cold is run totally separate in the UK, I still don't think this would do anything...

[kyteland]

I'm not sure exactly what you're saying here, but I'm assuming you mean they run each source in separate lines. That's the same in the US. The point is that these pipes aren't well insulated so the line has probably cooled even though it is a "hot" line. Running the water a little bit flushes the cooled water out so that only hot water goes into the dishwasher. Because even though it is a "hot" line it gets cold over time if it isn't being cycled. Maybe in the UK you're much closer to the hot water source, but in the US houses are often so big and poorly designed that you need to run the water a bit before you get really hot water from the tap.

[kuschku]

At least in Germany, dishwashers are hooked up to the cold water line. No matter what I do with my sink, the dishwasher will never get hot water on its inlet.

[kyteland]

Thanks, that was the context I was missing from the parent post. Makes total sense.