• Jamie McCroskery

Dishwasher detergents: reducing the carbon footprint by 88%

Updated: Sep 3

Truelabel uses algorithms based on climate research to estimate the carbon footprint of products, helping you reduce your impact while you shop without needing a Ph.D. in climate science.

We do this research because we believe people have a right to know the impact of what they’re buying (we do not take samples or funding from companies). Our research is based on Life Cycle Assessments, the gold standard for evaluating a product’s global warming impact holistically across its ingredients, manufacturing, packaging, etc.

image from good housekeeping institute

Does choosing a lower impact dishwasher detergent matter?

Like most things related to climate change, small things add up and can be traced back to critical sources of emissions -- oil production/use and deforestation. Choosing a dishwasher detergent with a lower carbon footprint won't stop climate change by yourself, but here's what it looks like if the entire US does so. The average American family’s use of dishwasher detergent equates to 130 hours of barbecuing or driving 400 miles (~160KG of CO2e).

If all US households switch to a low impact detergent, it'd be the equivalent of 29 times the carbon sequestered by Yosemite's forests every year (1).

Similar to other detergents, dish detergents are associated with emissions from sourcing chemicals to clean dishes (deforestation), packaging those chemicals (petrochemicals), transporting the detergent to you (petrochemicals), and finally putting it in your dishwasher (petrochemicals)and down the drain (eutrophication). Most emissions come from heating water actually, and the rest come from sourcing surfactants (i.e. Palm Oil) and packaging (i.e. petroleum or plants). That all said, if you wash your clothes on cold wash and choose one of the following detergents, you can reduce the footprint by more than 90%.

  1. The best: mineral-based or enzyme-based cleaners that use recycled packaging and don't come in polyvinyl pods

  2. Better: Detergents with coconut-derived surfactants

  3. Worse: Detergents using surfactants derived from petroleum, or worse, palm oil

OK, which dishwasher detergents have the smallest carbon footprints?

First and foremost, on average using dishwasher has a significantly lower carbon footprint than hand washing dishes in hot water (9). Past how you use detergents, here's the lowest carbon footprint dishwasher detergent by far:

Ecover Automatic Dishwasher Soap Tablets have an estimated 88% smaller carbon footprint required to get out of the factory compared to typical detergents, mostly coming from avoiding the use of plant-derived surfactants and using minimal, recycled packaging. For those really curious, emissions from materials are estimated at 95% lower than typical detergent, and packaging is estimated to be 54% lower than typical plastic buckets.

Why are we only pointing out one?

We ran other major options from Method, Seventh Generation, Rockin Green, Puracy, Mrs. Meyers, etc. and all had emissions multiple times higher. The only one that was close came from Powerball, surprisingly. When digging into it, emissions came out lower because it's mostly mineral based and it avoids polyvinyl alcohol pods. While we usually focus on carbon emissions, but we're not comfortable recommending it because it's possible their forming process is energy intensive (and uses fossil fuels, while Ecover uses renewable energy) and the other costs to the environment around biodegradability and human health are disproportionately high.

This all said, new products come onto the market every day, and we're scaling up our technology to survey even more products. But if you've found one you think is low emissions or have a DYI edition, let us know in the comments below!

For the data nerds, how we got these calculations

Because detergent-based products (e.g. soaps, laundry detergents, dish detergents) have similar raw material inputs, manufacturing processes, and packaging, the drivers of emissions to get the detergent out the factory door are similar.

  1. materials: 75% of emissions come from sourcing the raw ingredients (surfactants)

  2. manufacturing: ~13% of emissions come factory production

  3. packaging: 13% from the packaging of the detergent

Note: we're explicitly looking at a cradle-to-gate analysis, which means we're explicitly excluding emissions from use, transportation and disposal from our calculations. We do this for a few reasons: 1) emissions from use is similar across all products 2) people get their products in different ways (driving vs. Amazon) 3) each municipality has different disposal practices. This is to say, our calculations focus on giving you enough information to figure out which product to buy. From there, it's important to choose a low impact way of getting it (i.e. not 2nd day shipping, part of an existing order, etc.)

Sources: 2, 3, 4, 5

Emissions from Materials and Assembly

Like many other products, detergents start at the oil well, palm tree plantation, or mine. The raw ingredients that make up most of the emissions center around surfactant, the chemical compound that removes dirt and stains from your clothes. Surfactants are not all made equally and are divided into palm oil, petroleum, and even coconut oil surfactants. In total, about 75% of the emissions come from the raw ingredients that make up the detergent and 13% come from manufacturing processes (such as powering the factory that mixes these ingredients together). Critically, some detergents are mineral or enzyme based and actually avoid using plant or oil-based surfactants all together.

Emissions from Packaging

There’s a huge focus on developing packaging that’s small and sustainable or uses alternative, lower impact materials. This is great, because plastic, as we discuss here, is a big contributor of greenhouse gasses across the US economy. Compared to the typical detergent bottle you know, 100% post-consumer recycled packaging decreases emissions significantly, whereas using paper increases emissions significantly. Interestingly, pods coming in pouches drive much higher emissions because the the polyvinyl alcohol pod casing is resource intensive (6,7,8).

How to see through marketing: 

Now you know the science, but how do you actually read product labels and see when you're at the store (hint: you can use the Truelabel extension when shopping online so you don't have to read labels)? Here are common tricks used in eco marketing and how you can see through it.

“Plant-derived ingredients“

Verdict: this is a red herring, from a climate change perspective. "Plant-derived" is usually code for palm oil, which has a bad track record of clear cutting forests for production and comes with a huge carbon footprint. While sustainable palm oil certifications exist, on average palm oil is associated with 27% more emissions than petroleum, so it’s on the manufacturer to prove that they’re using “plant derived ingredients” that aren’t contributing to climate change and destroying virgin forests.

“Zero packaging" or "compostable packaging" or "bio-based” packaging

Verdict: this is a red herring, from a climate change perspective. If you want to have a zero waste life, that's great. But that might be separate from low carbon. Because surfactant choice is the largest driver of emissions, it's hard to prove trees weren’t cleared to make the detergent, you might be driving to your zero waste store, you shouldn't rely on packaging as an indicator of an overall low carbon footprint. For example, driving to the store to refill your container with detergent could blow out any saved emissions from packaging. Surfactants are also the most important driver of greenhouse gas emissions, so you could have a zero-packaging detergent that was made from clear cut forests. Bioplastics (corn or sugarcane-based) can reduce packaging emissions by 25% only if a company can verify they’re not contributing to deforestation to grow plants needed to create the bioplastics. That certification doesn’t really exist though, so it’s hard to know whether your bioplastic is truly helping.

"Made with Renewable Energy"

Verdict: it depends. Renewable energy is a good thing in lowering emissions for a product, but it doesn’t mean a product has low emissions. In other words, having a solar-powered factory using palm oil produced from deforested land doesn’t exactly mean the product will have a small carbon footprint. If you want to get into the details, it’s crucial to understand that not all renewable energy is created equal. Solar energy, for example, is cleaner than fossil fuels, but the production of solar cells emits powerful greenhouse gasses, therefore it has to be the main type of energy used by the company over a longer period of time for it to reduce emissions. Furthermore, hydroelectric energy requires the use of dams so water can turn turbines and produce energy. These dams, apart from being extremely expensive, lead to environmental degradation, flooding, and loss of habitats.Lastly, a company can be saying they use renewable energy by purchasing renewable energy credits, but that doesn’t necessarily mean that’s less dirty energy on the grid — they’ve simply bought the right to say they’re using green energy that’s already been produced. Using renewable energy is an important step to reducing emissions, but it doesn’t mean the product has low emissions.

Limitations and assumptions

While a LCA is an accurate method for estimating emissions of a product, there are limitations and assumptions we want to point out. 

  1. We calculate our percent changes by identifying a baseline product representing an example of the most commonly used product in that category. For example, for tissue products we used virgin wood since it is most commonly used by the world’s major paper-producing companies. 

  2. We also focus carbon emission equivalents from the product to better understand the climatic impact, which doesn’t take into effect impact on other aspects of the environment like biodiversity, pollution, etc.

  3. Our algorithm estimates carbon emissions and therefore isn't 100% accurate, That said, we believe empowering you with enough information to reduce emissions without knowing with 100% accuracy what that reduction is. If you’re a consumer or manufacturer who thinks we’re wrong, let us know or better yet prove us wrong by showing us your emissions. Furthermore, we can’t see into company supply chains, but as they become more forthcoming, this limitation will lessen. Lastly, we know that science changes day by day. As new products, technologies, and methodologies are developed, we will also evolve. This means our ratings and methodology will be continuously improved to reflect the most up-to-date research and so you can continue making a difference. 

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