[dijit]

I grew up handwashing too but I disagree with your assertion.

Firstly, you can't wash with cold water because soap doesn't activate with cold water, hot water also kills bacteria and helps cut through grease.

Fats themselves are hydrophobic and without activated soap you wont get them off... enjoy your "filmy" dishes.

Second, humans expend a lot more energy than you think. The act of standing and using our arms releases varying amounts depending on physical fitness but averages somewhere in the 1kg/h ballpark. https://www.jstage.jst.go.jp/article/jjphysiol/50/2/50_2_199...

Dishwashers use about 1800 Watts and are commonly run for 30 minutes, the average co2 in the USA is 0.92lbs per kWh.

Meaning it's _basically_ the same.

Then there's the freshwater usage, which is the real kicker, because dishwashers use significantly less freshwater, and freshwater filtering is the largest environmental impact of washing dishes (not the direct co2 output).

[JohnWhigham]

you can't wash with cold water because soap doesn't activate with cold water

Bunch of pseudoscience. I've never noticed any difference between washing with cold or not.

hot water also kills bacteria

Ultimately doesn't matter because they're all being washed away by the soap molecules anyway.

The act of standing and using our arms releases...

Lol, are you seriously trying to reason that what little energy you burn is more than a dishwasher?

[dijit]

> I've never noticed any difference between washing with cold or not.

Soap not activating when cold is not "pseudoscience", it's just a fact. Like grease doesn't become liquid unless heated. It's a similar principle.

> Ultimately doesn't matter because they're all being washed away by the soap molecules anyway.

If they bind, but, I'll give you this one.

> Lol, are you seriously trying to reason that what little energy you burn is more than a dishwasher?

Humans are pretty shitty at expending energy. This is one of the largest arguments against cycling long distances (though those arguments I don't agree with, but we're talking about total Co2 output here).

[BenjiWiebe]

I've worked in a cheese plant. The metal forms can be very greasy, and as the soap water cools off it is very noticeable that stuff doesn't want to get clean. Heat the water back up, and stuff cleans far easier.

[ClumsyPilot]

That energy use is likely an overestimate - thats mostky the heating element and it doesnt run the entire washing cycle or the water would boil

[jamincan]

Humans are expending energy regardless of whether they're washing dishes or not. The question is how much extra energy they expend when washing dishes over whatever they might do otherwise.

[readflaggedcomm]

>you can't wash with cold water because soap doesn't activate with cold water

That may be true for most laundry detergents, which have to pull grime out of fabrics, but not simple dish soap. Just look at how well Dawn works to take oil off concrete, for example. Nobody's heating that up.

[hippari]

Human body will have to expense energy regardless whether you do it with house chores, or going to the gym, or a walk in the park.