Review disclosure: Shoe Zero supplied this pair of Core Zero Low Tops free of charge after approaching Unsustainable Magazine about a review. This is an independent, first-person assessment based on three or four wears so far. Durability and the environmental figures discussed below have not been independently tested or verified.
When a shoe company offered to send me a pair to review, I had an unusual request: instead of my name, a pattern or a colourful logo, could the shoes display their own carbon footprint?
Shoe Zero agreed. The result is a pair of white, low-top sneakers with a little emblem on the side reading 18 kg CO₂e. That number was supplied by the company in response to my request. It is not a standard design or a footprint label applied to all Shoe Zero products.
I wanted to know what would happen if a product’s environmental cost was made visible rather than hidden behind its branding. Now that I’ve worn the shoes a few times, I have two quite different impressions: they’re remarkably comfortable, but the environmental story is much less straightforward.
First impressions: an unexpectedly good fit
I hadn’t measured my feet particularly carefully for a shoe order before, and when these arrived I immediately worried I’d chosen the wrong size. Getting my foot into the shoe was difficult. For a moment, I was convinced they were going to be too small.
Then my foot was in, and the fit felt almost perfect. The shoes were snug without squeezing or crushing my feet. That initial struggle didn’t translate into discomfort once I was wearing them.
The biggest surprise has been how comfortable they feel. I’ve worn them three or four times in fairly warm Australian weather, and my feet have stayed pleasantly cool. Despite the synthetic upper, I haven’t noticed the sweaty, stuffy feeling I sometimes associate with enclosed sneakers. That’s an observation about my feet and these particular outings, not a laboratory breathability test or a promise about how they’ll feel for everyone.
Visually, they’re simple white sneakers with a dark heel detail. The carbon-footprint emblem makes them unusual, and the custom printing looks tidy in the photographs I’ve taken. It’s still far too early to judge how well the material, stitching, sole or printed graphic will age.
What are the Core Zero Low Tops made from?
According to Shoe Zero’s product specifications, the Core Zero Low Tops use a polyurethane (PU) synthetic-leather upper, a rubber outsole and a removable ethylene-vinyl acetate (EVA) insole. The brand describes the upper as “eco-friendly synthetic leather”, although the information supplied on that page does not establish what makes this particular PU material environmentally preferable.
These are familiar footwear materials, and that is an important distinction. PU and EVA are synthetic polymers ordinarily made using fossil-derived feedstocks. Calling synthetic leather “vegan” can tell us that it is an alternative to animal leather; it does not, by itself, establish a low environmental footprint, biodegradability or circularity. We’ve explored that distinction more fully in our guide to vegan shoes and the claims surrounding them.
Made to order: a meaningful advantage, with limits
One aspect of Shoe Zero’s business model genuinely interests me. The company says it prints each pair to order rather than manufacturing finished printed shoes for stock. Customers choose a shoe model and upload their artwork, and the panels are printed before being cut and assembled.
Shoe Zero describes water-based printing inks, laser-cut panels, stitched assembly, an adhesive bond between upper and sole, and a protective PU-acrylic topcoat. These are the company’s descriptions of its processes, rather than independently audited environmental findings.
In response to my follow-up questions, Shoe Zero clarified that each pair is built after an order arrives, rather than produced as finished stock for a warehouse or a seasonal collection. The company says it holds almost no inventory beyond basic materials and orders those materials monthly in quantities based on expected demand. That approach may avoid unsold finished shoes and reduce surplus material.
Making a pair against an actual order can help avoid one particularly unnecessary kind of waste: finished products that nobody ever buys. That is a real potential benefit in an industry where unsold goods and returns can have environmental costs. The European Environment Agency has documented the environmental pressures associated with textiles and footwear production, while our article on custom apparel and waste discusses the trade-offs of production on demand.
Where did the 18 kg CO₂e figure come from?
This is the most distinctive part of my pair, but not something I can independently substantiate. Shoe Zero clarified that its 18 kg CO₂e figure is an indicative per-pair estimate, not an audited carbon footprint. The company also confirmed that it has not published a stage-by-stage lifecycle breakdown. I appreciate that clarification: readers deserve to know what the label can, and cannot, establish.
CO₂e means carbon dioxide equivalent: a way of expressing the warming impact of different greenhouse gases in common units.
For perspective, a published lifecycle assessment of a particular synthetic running shoe estimated about 14 ± 2.7 kg CO₂e per pair. Its authors reported that manufacturing and materials processing dominated that case study’s total. That’s useful context, but it does not validate 18 kg for this very different shoe.
The European Commission has also highlighted the need for consistent, lifecycle-based methods for assessing apparel and footwear. Without boundaries and supporting data, a number printed on a sneaker is a conversation starter, not an independently verified environmental label.
I appreciate both Shoe Zero’s willingness to try this unusual design and its acknowledgment that the footprint number is only indicative. A more detailed explanation of the calculation and its lifecycle boundaries would still be valuable, and I’ll update this review if those details become available.
My early verdict: good shoes, with some environmental upsides
After three or four wears, I like these sneakers more than I expected to. They feel comfortable, the fit is snug in the right way once they’re on, and they’ve felt cool even in warm weather. I’d be happy to keep wearing them, which is an important quality in any item we hope to keep out of the waste stream.
The sustainability verdict is much less settled. I like Shoe Zero’s made-to-order approach for avoiding unsold finished inventory, and the company has explained how it also tries to limit surplus raw materials. But those potential waste and emissions savings are unquantified. These shoes still use conventional synthetics, recycled materials are only being explored for future products, and no repair or recycling pathway has been announced. Shoe Zero also confirms that the 18 kg CO₂e number printed on my pair is indicative rather than audited.
So would I recommend them? As comfortable, customisable casual shoes, my early experience is encouraging. As demonstrably low-impact footwear, I don’t yet have the evidence to make that claim. Time will tell!