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A 2.5-5gal sink (lets average it at 3.75gal) filled 3/4 of the way twice is 5.6gal (2.1825 * 2). My dishwasher uses 3.5gal for a larger load than what I'd like

A 2.5-5gal sink (lets average it at 3.75gal) filled 3/4 of the way twice is 5.6gal (2.1825 * 2). My dishwasher uses 3.5gal for a larger load than what I'd like to do in a sink. 5.6 > 3.5.

dredmorbius 3y ago
The difference between the most efficient machine vs. hand-washing methodologies are really too small to matter. A gallon or so of water either, way, most especially if cold, isn't worth worrying about. There are other sources of inefficiencies in using a dishwasher as I've noted above. My point isn't to browbeat people into hand-washing dishes. Rather, it's to point out that there are real advantages to doing so, and if that's what you prefer you shouldn't beat yourself up over it on account of efficiency arguments. A few years back I'd looked up the actual research on hand-washing vs. machine washing. The most-quoted study (where any study is quoted at all, rather than vague hand-waving) is from the University of Bonn, Germany: "A European Comparison of Cleaning Dishes by Hand", Rainer STAMMINGER, Ricarda BADURA, Gereon BROIL, Susanne DÖRR, Anja ELSCHENBROICH. University of Bonn, Germany. <https://web.archive.org/web/20150701173343/www.landtechnik-alt.uni-bonn.de/ifl_research/ht_1/EEDAL_03_ManualDishwashing.pdf https://web.archive.org/web/20150701173343/www.landtechnik-a...> The upshot: - Practices for hand-washing vary widely. Some are exceedingly efficient. Some are stupendously wasteful. - There's a considerable variation by country, or by region of the US. - The best hand-washing methods beat dishwashers. Many of the rest come close. Among the most efficient hand-washers are Germans, Californians, and Australians. The latter two live in areas where water is chronically limited. The least efficient: Russians. If you fill a sink basin or small dish bucket, you've got about 2 gallons of water accounted for (the most efficient dishwashers use at least 4, many use 6 or somewhat more). Rinsing may in another basin, or under the tap in the sink. If you live in a multi-person household and can fill a dishwasher every day or so, and hate doing dishes, the dishwasher makes sense. If you live alone or can't fill the dishwasher, or would be washing dishes anyway, hand-washing may be more effective. Either way, so long as you're not performing the Russian method: hot water tap full on during the full period you're washing dishes, hand-wasing can be the most efficient water- and energy-wise. And if you hate hand-washing, and have a dishwasher, then use it. Neither side in this discussion should be browbeating the other
- vel0city 3y ago
  I do imagine there are some who truly are more efficient handwashing than using a dishwasher, but from your link: > Additionally it was shown that new dishwashers are able to reach at least the same performance with significant less amount of water needed as any test person Also, the chart shows the average water use for a lot of these countries is somewhere close to 100L of water. Even for the lows of Germany/GB the average is around 50L. 3.5gal is only ~13L of water. So by this document my dishwasher is 3.8x as efficient as the average German doing dishes and almost 8x more efficient as many other countries, but I do agree this study doesn't exactly have massive sample sizes and there's a massive range of variability. I do generally agree though we're (usually) talking about somewhat insignificant amounts of water "wasted" either way. I use far more water for bathing, drinking/eating, and flushing throughout my day, and we're talking about a few hundred kWh of energy used over a year when my monthly usage is >1000kWh. In the end I agree, people should generally do what's comfortable for them, save for just letting the hot water run while doing a lot of dishes. But this idea that the average person handwashing dishes is radically more efficient just isn't reality, and most people would have to seriously try to be more water/energy efficient than most dishwashers on the market today. The average person's techniques for washing dishes by hand just isn't as efficient as any modern dishwasher. That's probably fine, but also lets not ignore reality.

A 2.5-5gal sink (lets average it at 3.75gal) filled 3/4 of the way twice is 5.6gal (2.1825 * 2). My dishwasher uses 3.5gal for a larger load than what I'd like to do in a sink. 5.6 > 3.5.

dredmorbius 3y ago

The difference between the most efficient machine vs. hand-washing methodologies are really too small to matter. A gallon or so of water either, way, most especially if cold, isn't worth worrying about. There are other sources of inefficiencies in using a dishwasher as I've noted above. My point isn't to browbeat people into hand-washing dishes. Rather, it's to point out that there are real advantages to doing so, and if that's what you prefer you shouldn't beat yourself up over it on account of efficiency arguments. A few years back I'd looked up the actual research on hand-washing vs. machine washing. The most-quoted study (where any study is quoted at all, rather than vague hand-waving) is from the University of Bonn, Germany: "A European Comparison of Cleaning Dishes by Hand", Rainer STAMMINGER, Ricarda BADURA, Gereon BROIL, Susanne DÖRR, Anja ELSCHENBROICH. University of Bonn, Germany. <https://web.archive.org/web/20150701173343/www.landtechnik-alt.uni-bonn.de/ifl_research/ht_1/EEDAL_03_ManualDishwashing.pdf https://web.archive.org/web/20150701173343/www.landtechnik-a...> The upshot: - Practices for hand-washing vary widely. Some are exceedingly efficient. Some are stupendously wasteful. - There's a considerable variation by country, or by region of the US. - The best hand-washing methods beat dishwashers. Many of the rest come close. Among the most efficient hand-washers are Germans, Californians, and Australians. The latter two live in areas where water is chronically limited. The least efficient: Russians. If you fill a sink basin or small dish bucket, you've got about 2 gallons of water accounted for (the most efficient dishwashers use at least 4, many use 6 or somewhat more). Rinsing may in another basin, or under the tap in the sink. If you live in a multi-person household and can fill a dishwasher every day or so, and hate doing dishes, the dishwasher makes sense. If you live alone or can't fill the dishwasher, or would be washing dishes anyway, hand-washing may be more effective. Either way, so long as you're not performing the Russian method: hot water tap full on during the full period you're washing dishes, hand-wasing can be the most efficient water- and energy-wise. And if you hate hand-washing, and have a dishwasher, then use it. Neither side in this discussion should be browbeating the other

vel0city 3y ago
I do imagine there are some who truly are more efficient handwashing than using a dishwasher, but from your link: > Additionally it was shown that new dishwashers are able to reach at least the same performance with significant less amount of water needed as any test person Also, the chart shows the average water use for a lot of these countries is somewhere close to 100L of water. Even for the lows of Germany/GB the average is around 50L. 3.5gal is only ~13L of water. So by this document my dishwasher is 3.8x as efficient as the average German doing dishes and almost 8x more efficient as many other countries, but I do agree this study doesn't exactly have massive sample sizes and there's a massive range of variability. I do generally agree though we're (usually) talking about somewhat insignificant amounts of water "wasted" either way. I use far more water for bathing, drinking/eating, and flushing throughout my day, and we're talking about a few hundred kWh of energy used over a year when my monthly usage is >1000kWh. In the end I agree, people should generally do what's comfortable for them, save for just letting the hot water run while doing a lot of dishes. But this idea that the average person handwashing dishes is radically more efficient just isn't reality, and most people would have to seriously try to be more water/energy efficient than most dishwashers on the market today. The average person's techniques for washing dishes by hand just isn't as efficient as any modern dishwasher. That's probably fine, but also lets not ignore reality.