Dishwasher vs. Hand-Washing Dishes

Today we’re going to compare using a dishwasher vs hand washing your dishes. Along the way we’ll share some fascinating research we think you’ll love.

Let’s jump right in.

1. Dishwasher vs hand-washing: efficiency

You’ve probably seen it repeated time and time again. Everyone “knows” that dishwashers are more efficient that washing dishes by hand.

Or are they?

A recent study pointed out that this assumes that you are comparing the most efficient dishwasher there is with the least-efficient hand-washing method there is (namely: leaving the tap running the entire time).

That’s like comparing apples to oranges.

The study conducted at the University of Michigan found that the most efficient dish-washing method of all is to hand wash the dishes using the “two-sink” method.

This consists of filling one sink with soapy water to wash the dishes, and rinsing them in the other sink.

That method, the researchers found, is more efficient in terms of both energy and water consumption than even the most efficient dishwasher.

In particular, the study emphasized that hand washing dishes has lower greenhouse gas emissions (1,610 kg CO2) than even the most modern dishwasher (1,960 kg CO2) over a 10-year period.

That means you can lower your dish-washing CO2 emissions by 18% simply by washing the dishes by hand.

That’s pretty cool!

2. The pre-rinsing problem

You’ve surely seen blog posts and advertisements touting state-of-the-art dishwashers that use less than 3 gallons of water per load.

That’s nice, but here’s the thing.

Such numbers are not based on real-world consumer behavior.

A Virginia Tech study revealed that 93% of US dishwasher owners pre-rinse their dishes.

Pre-rinsing can use up to 25 gallons of water, which increases the true amount of water and energy consumed when you run the dishwasher.

Researchers at UCLA came to a similar conclusion.

And there’s more.

3. The re-washing problem

Have you ever used a dishwasher, only to discover that some of the dishes came out dirty? You’re not alone.

Researchers discovered that 54% of dishwasher owners in the US say their dishes don’t come out of the dishwasher clean enough.

In fact, 74% are less than happy with their dishwasher’s results.

That means there’s a lot of hand washing the dishes going on, even in dishwasher-using households.

They’re just hand-washing dishes that have already come through the dishwasher.

This adds to the water and energy consumption, causing the dishwasher to have a far higher environmental impact than what dishwasher manufacturers want us to think.

Not good.

4. Drying the dishes

If you do own a dishwasher and are determined to continue using it, consider turning off the “dry” cycle.

Here’s why.

The dry cycle uses about 0.2 kW/h of energy – energy that could be easily saved.

Instead, when the dishwasher has finished its job, open the dishwasher door to allow the dishes to air dry.

A recent study found that 11% of a dishwasher’s energy consumption is used on drying the dishes, and 54% of dishwasher owner use the dry cycle.

That’s where hand washing has a huge advantage.

After hand-washing the dishes, simply place them on a drying rack (you gotta see this one – it’s amazing), go do something else, and come back when they’re dry.

That’s zero energy used for drying the dishes.

5. Half-full cycles

How many times have you run a dishwasher without filling it up completely?

We get it.

Life is busy, and sometimes you need to use an item that’s currently dirty.

Or maybe your household is small, and doesn’t go through dishes fast enough to fill up the dishwasher.

Unfortunately, running a half-full cycle doubles the water consumption, energy consumption, and greenhouse emissions per dish.

While (as we saw earlier) hand-washing with the two-sink method is always more environmentally-friendly than running the dishwasher, half-full cycles are an especially great reason to hand-wash.

6. Water temperatures

Manufacturers pride themselves that the water inside dishwashers reaches high temperatures.

They claim that this gets dishes cleaner and removes more microbes than can happen at a lower temperature.

Unfortunately, it doesn’t.

Researchers at Rutgers University investigated the effectiveness of different water temperatures for removing germs.

After testing water temperatures of 60˚F, 79˚F, and 111˚F, they found that temperature in this range does not matter.

Yep, you read that right.

The study showed that cool water removes microbes just as well as warmer water. Another study from Ohio State University found similar results.

So washing the dishes at the higher temperatures found inside your dishwasher doesn’t provide any added benefit.

Unfortunately, it does cause harm.

A study by researchers at the University of Central Florida found that water-heating accounts for 60% of a dishwasher’s entire energy consumption (averaging 0.9 kW/h per cycle).

The bottom line?

When you hand wash dishes with cool water, your dishes turn out just as clean, and without wasting energy on hot water.

7. The dishwasher’s short lifespan

About 70% of US households own a dishwasher.

According to the US Energy Information Administration, 20% of US dishwasher owners use their dishwashers less than once per week.

Owning a dishwasher but not using it is problematic, since dishwashers have a typical lifespan of 10 years.

But producing the dishwasher in the first place was a resource-intensive process, and replacing it will also consume a lot of resources.

This takes us to the next issue.

8. Recyclability

If a dishwasher breaks, you know what to do. You simply order a new one, and let the department store pick up and recycle the old one.

Easy enough, right?

According to the Environmental Protection Agency (EPA), a staggering 38% of kitchen items are never recycled, but rather, go straight to the landfill.

That might sound like relatively good news; after all, it means that most kitchen items get recycled.

But “recycling”, in this case, still generates some landfill waste.

Dishwashers that are lucky enough to get recycled end up getting shredded in order to separate their plastic from their metal parts.

Only the metal parts get recycled, while the plastics and other materials are sent to the landfill.

That results in approximately 50% of a dishwasher’s materials not getting recycled.

While that’s certainly better than nothing, there is an even more environmentally-friendly option: hand washing the dishes.

If this speaks to you, then when your dishwasher breaks, consider replacing it with extra cabinet space instead of with another dishwasher.

9. Repair costs

We’ve all been there: you load up the dishwasher, and nothing happens. Or, the wrong thing happens: water starts leaking all over the floor.

Consumer Reports found that 30% of all dishwashers break within the first 5 years.

Sounds like buying a dishwasher is quite a gamble!

And when they break, the repair cost isn’t cheap.

Angie’s List calculates that the average dishwasher repair cost in the US is $159 for labor. Often, service providers add a $75 trip charge, for a total cost of over $200.

And the repair cost of hand-washing your dishes? Zero.

10. Nasty dishwasher odor

It’s quite ironic that the appliance that’s used to clean the dishes often tends to smell… not so clean.

Often that’s due to food particles getting stuck in the filter. If that’s the case, you can clean the filter.

Sometimes the bad odor comes from mold that thrives in the dark, moist environment inside the dishwasher.

You can remedy this by washing the inside of the dishwasher with some dish soap, and leaving the dishwasher door open to allow it to air dry.

Luckily, that’s one more issue you don’t have to worry about when hand washing the dishes.

11. Black yeast

Sometimes the bad odor in dishwashers is more than a nuisance. Sometimes, its source can make you sick.

A team of international researchers discovered that one of the fungi that often thrives in dishwashers is black yeast – a potentially dangerous pathogen to humans.

After collecting samples from dishwashers in 101 cites on 6 continents, the research team found that 35% of the dishwashers in their study were home to black yeast.

The pathogen grows on the rubber that seals dishwasher doors.

Unfortunately, it isn’t the least bit discouraged by harsh detergents or high levels of heat inside dishwashers.

Black yeast can make humans sick, and can even be fatal.

It’s much safer to hand wash the dishes instead.

12. Indoor air pollution

A study conducted at the University of Texas at Austin College of Engineering discovered that dishwashers release chemicals such as radon, petrochemicals, and chlorine into the air.

How?

Because of their high temperatures, dishwashers are rather good at separating such toxins from the water and releasing them into the air once the dishwasher door is opened.

Since indoor air pollution is more harmful than outdoor pollution due to the time that you spend indoors, you should air out your kitchen once a dishwasher cycle is done.

Hand washing dishes, on the other hand, poses no such risk (especially when using the most natural dish soap there is).

13. Water damage

No matter how you feel about your kitchen cabinets – love ‘em or hate ‘em – you probably aren’t too crazy about water damage.

Here’s the thing. The humid air that comes from your dishwasher can damage your kitchen's cabinets over time.

There’s a high price to pay. Replacing your kitchen cabinet would average about $25,000 (or $150 per square foot).

At that price, that’s a strong incentive to keep those cabinets safe.

The easiest solution? You guessed it: simply hand-washing the dishes.

14. Danger for kids

Know those liquid detergent pods for dishwashers?

Their scent and texture makes them attractive to children, especially ages 4 and under.

These pods burst open easily when squeezed or bitten.

This has landed some children in the emergency room with severe eye injuries.

And if children swallow the detergent, it destroys tissue inside their bodies, causing intense inflammation and swelling.

Why run the risk when you can hand wash the dishes with a natural dish soap instead?

If you choose a non-toxic dish soap made with no synthetic chemicals, you need not worry about any such dangers.

Choosing a safer option is good not just for your kids, but for your whole household. (Find out more here).

15. Gotta hand-wash anyway

So many kitchen utensils that cannot be washed in a dishwasher.

If you’re interested in an exhaustive list of items that aren’t dishwasher safe, you can access them in this post.

But in general, your cutting tools and everything made of plastic, wood, cast iron, or Teflon needs to be washed by hand no matter what.

We already mentioned, too, the problem of “post-washing”: the fact that most dishwasher owners end up re-washing dishes by hand that came out of the dishwasher still dirty.

Long story short, most people end up having to hand wash a significant chunk of their dishes anyway.

Why not save the hassle of loading and unloading the dishwasher, and quickly wash them by hand instead?

16. Dishwasher vs hand washing: miscellaneous

Owning a dishwasher certainly comes with some advantages.

Damaging the dishes is less likely when all you have to do is place them inside the dishwasher instead of washing them by hand.

Also, your kitchen will look more appealing when you store dirty dishes in the dishwasher instead of the countertop or the sink.

Definitely a perk while hosting guests.

Over to you

We hope you learned a few interesting facts in this post.

Want to learn even more?

Join us to learn about areas that most people forget to clean in the kitchen. You might learn of an area or two that your current routine is neglecting!

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