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Dishwasher or handwashing dishes? Which is better for the environment, saves more money, and is more hygienic?

You load and start your dishwasher. The washing process begins, and you hear a rush of water, followed by what appears to be a large amount of water.

And then, you start to think,Oh My God, this can’t be good for the environment. Or are you just scaring yourself? Let’s find out with PAA.

Video: Dishwasher or handwashing dishes? Which is better for the environment, saves more money, and is more hygienic?

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Hi, I am Shao Chieh Lo, welcome to what people also ask, where I search something seemingly obvious and share with you some of its PAA, aka People Also Ask, which is a feature telling you what other people are searching on Google that relates to your query.

 

So let’s start with our first PAA:

 

Is it better for the environment to hand wash or use the dishwasher?

This question is answered by an article titled “What’s More Sustainable: Handwashing or Using a Dishwasher?” published by Green Matters, which is a lifestyle media company covering sustainability and innovation-related news.

And another article titled “Should You Clean Your Dishes by Hand or Use a Dishwasher? Here’s the Answer”  published by Angi (formerly Angie’s List) which is an American home services website owned by Angi Inc. headquartered in Indianapolis, Indiana.

According to these two articles, believe it or not, using a dishwasher can actually be the more sustainable and environmental-friendly option.

In some cases, dishwashers reduce water consumption, are more efficient than hand washing, and can even save you money. Dishwashers use less water, even if you don’t have an Energy Star dishwasher. 

For those who don’t know, Energy Star is a government-backed labeling program that helps people and organizations save money and reduce greenhouse gas emissions by identifying factories, office equipment, home appliances, and electronics that have superior energy efficiency.

So let’s break down the following up questions into three parts: Water, electricity, and money.

So first,

 

Does Dishwasher use more water than handwashing dishes?

According to The Alliance for Water Efficiency, Energy-Star dishwashers use about 3 1/2 gallons of water per cycle while older models use between 10 and 15 gallons.

While this is a significant difference, it pales in comparison to the amount of water used while washing dishes by hand. 

Kitchen faucets use 1 1/2 to 2 gallons of water per minute. On average, hand-washing dishes uses between 9 to 27 gallons per load, but this widely varies based on washing methods.

So handwashing usually uses more water than Energy-Star dishwashers, and can even potentially use more water than older models of dishwashers depending on your washing method.

 

Does Dishwasher use more energy than handwashing dishes?

While hand-washing appears to consume no electricity, it requires a tremendous amount of energy to clean water for you to use. So, in terms of the environment, a dishwasher still uses less energy than hand-washing.

According to one study at the University of Bonn in Germany, in general, the households with dishwasher used on average 50% less water and 28% less energy per cleaned item compared with households not owning a dishwasher.

And according to United States Environmental Protection Agency, if you have an Energy Star dishwasher you can potentially save 55,000 gallons of water over 11 years (which is the average lifespan of an Energy Star dishwasher), compared to washing by hand.

 

Is it cheaper to wash dishes by hand or by dishwasher?

According to the articles mentioned above. Energy-efficient dishwashers that meet the Environmental Protection Agency‘s electricity and water-saving efficiency standards might save  a home on average $25 per year in energy bills.

And according to another document of the United States Environmental Protection Agency, if you have an Energy Star dishwasher you can potentially save an average of $465 in water and energy bills over 11 years, compared to washing by hand.

So here’s another question, how can dishwashers actually use less water? Let’s talk about our next PAA:

Do dishwashers reuse dirty water?

The short answer is yes.

This question is answered by an article titled “Appliance Science: Dishwashers and the physics of water” published by CNET, which is an American media website that publishes reviews, news, articles, blogs, podcasts, and videos on technology and consumer electronics.  And another article titled “WHAT ACTUALLY HAPPENS INSIDE YOUR DISHWASHER?”  published by reviewed.com, which is a consumer product review website based in Cambridge, Massachusetts, and emphasizes a science-based approach that tests consumer products in both everyday and lab environments.

According to these two articles, all dishwashers have the same basic design: a sink at the bottom that fills with water, a pump that transports this water, and spray arms, sprayers, and other mechanisms that shoot this water onto the dishes.

And all dishwashers recycle water to conserve water. The dirty water eventually drips back into the pool below, where it is filtered, reheated, and sent back out into the spray arm again. The same water is being constantly used and reused, heated and reheated, sprayed and collected. 

And here’s what actually happens during a modern dishwasher cycle:

  1. Pre-rinse

This is the first burst of warm water via the spray arm, which gets all of the dirty dishes wet but doesn’t really aim to clean.

  1. Main wash

This is the main part of the wash cycle that will use recycled water. The water is heated, sprayed, collected, filtered, reheated, and re-sprayed.At the end of the main wash, all of the water is drained.

  1. Final wash and rinse

And finally, the dishwasher will pull in new, clean water and finish up with a final rinse.

 

Is using a dishwasher more hygienic than hand-washing dishes?

The question is answered by an article titled“Dishwashers or hand-washing? Science settles the score” published by Columbia Tribune. This article argued that dishwashers are more sanitary than handwashing dishes.

Assume that someone in your family has been sick. Is it best to scrub your dishes by hand or put them in the dishwasher to get rid of germs?

One way to kill bacteria is to use really hot water. Dishwashers wash dishes with much hotter water. The hot water kills the majority of the bacteria that have been growing on your unclean dishes. Your hands would be scalded if you used the same temperature of water in the dishwasher to hand wash your dishes.

Dishwashers, however, are not bacteria-free. According to scientific studies, germs can be discovered in 100% of dishwashers. 

The difference is that in nearly all of the studies, the bacterium found in dishwashers are less harmful to humans. 

Washing dishes by hand contains considerably more harmful bacteria, owing to the bacteria growing on the rag, sponge, or towel you are using.

Especially the sponge. According to an article titled “A sponge may not be the most hygienic way to clean dishes, study suggests, but there is an alternative” published by CNN and a research published in 2022 titled “Bacterial levels and diversity in kitchen sponges and dishwashing brushes used by consumers”, Salmonella and other bad bacteria grow and survive better in sponges than in brushes, the reason is that sponges in daily use never dry up.

So in terms of health concerns, should you always use the dishwasher? There is actually one exception: if you have smaller kids in your household, then you might want to handwash some of your dishes.

There is a lot of research that shows that kids who grow up in super-clean environments have more allergies than kids who grow up in “normal” environments.

To be more precise, we are only talking about young children. Your allergies are very well set by the time you’re an adult, so this wouldn’t make much of a difference. 

Families with babies and small children, on the other hand, may want to wash some of their dishes by hand so that some bacteria enter their child’s system. Little germs in a child’s life has been shown to enhance the immune system and lead to a healthier life than children raised in ultra-clean conditions.

 

 

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Reference:

What’s More Sustainable: Handwashing or Using a Dishwasher?

https://www.greenmatters.com/p/dishwasher-handwash-dishes-sustainable

Should You Clean Your Dishes by Hand or Use a Dishwasher? Here’s the Answer

https://www.angi.com/articles/hand-washing-vs-dishwasher-cost.htm 

Appliance Science: Dishwashers and the physics of water

https://www.cnet.com/home/kitchen-and-household/appliance-science-dishwashers-and-the-physics-of-water/ 

WHAT ACTUALLY HAPPENS INSIDE YOUR DISHWASHER?

https://www.reviewed.com/dishwashers/features/what-actually-happens-inside-a-dishwasher

Dishwashers or hand-washing? Science settles the score

https://www.columbiatribune.com/story/news/2021/09/29/dishwashers-hand-washing-science-settles-score/8418843002/ 

A sponge may not be the most hygienic way to clean dishes, study suggests, but there is an alternative

https://www.cnn.com/2022/06/07/health/dish-washing-sponge-vs-brush-scn-wellness/index.html

Bacterial levels and diversity in kitchen sponges and dishwashing brushes used by consumers

https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/jam.15621 

 

CC resources:

 

  1. Dishwasher_RevisOPENER_FINAL

 https://vimeo.com/240081633 

Beko – Tag Dishwasher

https://vimeo.com/715233734 

 

3D Animation | STERIS | Technical Demo for Industrial Dishwasher

https://vimeo.com/279861693