Recycled Polyester vs Recycled Cotton: Which Fiber Slashes Carbon Emissions Faster in 2025?

You want to cut your brand's carbon footprint. Recycled fibers are key, but which one—recycled polyester¹ or recycled cotton²—makes a bigger, faster impact on CO₂?

Recycled polyester (rPET) generally offers a larger reduction in carbon emissions compared to virgin polyester. Recycled cotton (RC) significantly cuts water, land, and chemical use versus virgin cotton. The faster CO₂ cut in 2025 often depends on the comparison point (virgin fiber) and specific recycling process.

As Sales Manager at regenFabrics, I see brands wrestling with this choice every day. We work with both recycled cotton and recycled polyester in our blends, like TC and CVC fabrics. Understanding the real environmental numbers behind each fiber is vital for making claims you can stand by. It is not always a simple answer because their starting points and processes are so different. Let's look closer at the data in 2025.

Lifecycle‑Emissions Snapshot: RPET vs RC?

Comparing the full environmental picture of recycled polyester and recycled cotton reveals different strengths. Which one saves more CO₂ in a typical product life?

RPET generally has a lower carbon footprint compared to virgin polyester, primarily by avoiding the need for new plastic production. RC has a lower footprint than virgin cotton, mainly by skipping the energy-intensive growing stage, but the energy used in recycling varies.

When we talk about cutting carbon emissions, we need to look at the whole life of the fiber. This is called a lifecycle assessment³ (LCA). For recycled polyester (rPET), the big win for carbon comes from not having to make new polyester. New polyester is made from fossil fuels, which releases a lot of greenhouse gases. rPET is usually made from old plastic bottles (like PET bottles). Turning a plastic bottle into fiber uses less energy than making new plastic from oil. Studies, like those often seen in Higg MSI data updated for 2024-2025, show that rPET can lower carbon emissions by a good amount compared to virgin polyester – often 30% to 50% or even more, depending on the exact recycling process and energy source used. Recycled cotton (RC) starts from textile waste, not new cotton plants. Growing new cotton needs a lot of energy for farming machines, fertilizers, and sometimes irrigation. By using cotton waste, recycled cotton skips most of this farming energy. This is where it gets its main carbon savings compared to virgin cotton. However, the recycling process for cotton (especially mechanical recycling, which is more common) also uses energy. Chemical recycling for cotton, which is newer, can be more energy-intensive but also can make higher quality fiber. When comparing rPET to RC directly on CO₂ per kilogram of fiber, it is complex. rPET often shows a larger percentage reduction compared to its virgin version than recycled cotton does compared to virgin cotton. But virgin polyester production has a much higher carbon footprint to start with than virgin cotton farming. So, a large percentage cut from a very high number (virgin polyester) can be a bigger absolute CO₂ saving than a moderate percentage cut from a lower number (virgin cotton). However, the energy used in recycling cotton, especially mechanical shredding, can be significant depending on the machinery. Chemical recycling of cotton requires more energy but can unlock more waste types. In 2025, rPET from bottles is widely available and shows clear carbon savings. Recycled cotton's carbon saving is also real, mostly from avoiding farming. The "faster" cut often means looking at which virgin fiber you are replacing. Replacing virgin polyester with rPET usually gives a big, direct carbon benefit. Replacing virgin cotton with RC gives a benefit by avoiding farming impacts, but the recycling process itself matters for the final CO₂ number.

What Makes Each Fiber “Recycled”?

Recycled polyester and recycled cotton both come from waste, but the waste material and the process to turn it into new fiber are very different. What is the story for each?

Recycled polyester (rPET) is primarily made from plastic bottles and packaging through melting and re-extruding. Recycled cotton (RC) is made from textile scraps and old clothing through mechanical shredding or chemical processes.

Understanding the source material and process for each fiber helps explain their properties and environmental effects. For recycled polyester (rPET), the most common source material today is post-consumer waste, specifically used plastic bottles and food packaging made from PET plastic. These bottles are collected, sorted, cleaned, and then processed.

How Post‑Consumer Plastics Become RPET Yarn

The process to turn plastic bottles into rPET fiber usually involves these steps:

1. Collection & Sorting: Used PET bottles are collected (e.g., through recycling programs). They are sorted to remove other plastics and materials.
2. Washing & Grinding: The clean PET bottles are washed and then ground into small flakes.
3. Melting & Filtering: The PET flakes are heated and melted into a liquid form. This liquid is filtered to remove any remaining impurities.
4. Extrusion & Spinning: The melted plastic is pushed through small holes (like a showerhead) called a spinneret. As the thin streams of melted plastic come out, they cool and harden into long fibers. These fibers are then stretched and processed into yarn.

This process avoids the energy-intensive steps of making new polyester from raw materials like oil and natural gas.

Turning Textile Waste into Recycled Cotton Fiber

Recycled cotton (RC) uses different waste materials and processes. The source material is cotton textile waste, which can be:

1. Pre-Consumer Waste: Scraps and cuttings from factories making clothes or other textiles. This waste is usually cleaner and easier to process.
2. Post-Consumer Waste: Old clothes, towels, sheets, and other cotton textiles thrown away by people. This waste is more complex, often mixed with other fibers, dyed, and worn out.

The processes to turn this textile waste into new cotton fiber are mainly mechanical or chemical:

1. Mechanical Recycling: This is the older and more common method for cotton. It involves physically shredding and tearing the fabric waste using machines. This breaks the fabric down into fibers. The process often shortens the cotton fibers and can damage them. The resulting fibers are often blended with other fibers (like new cotton or rPET) to be spun into yarn.
2. Chemical Recycling: This is a newer technology for cotton. It uses chemicals to dissolve the cellulose (the main part of cotton) in the waste textile. Impurities like dyes and other fibers can be removed. The pure cellulose is then made into new fibers through a process similar to making fibers like Viscose or Lyocell. This method can process more complex waste (like blends) and aims to produce higher quality fibers closer to virgin cotton. However, it is more complex and requires careful chemical management.

So, rPET comes from plastic bottles through a melting process, while RC comes from fabric waste through physical tearing or chemical dissolving. These different starting points and processes lead to fibers with different properties and environmental profiles.

Cradle‑to‑Gate Carbon Footprint Breakdown?

Where do the carbon emissions happen most in the life of recycled polyester and recycled cotton before they become a finished fabric (from raw material to factory gate)?

The biggest carbon savings for rPET happen by avoiding virgin plastic production. For RC, savings come from avoiding cotton farming. Energy use in the recycling process itself is a key part of the footprint for both.

To understand the carbon footprint from "cradle to gate" (from getting the raw material to the finished fiber or yarn leaving the factory), we need to look at each step.

Raw‑Material Collection & Transport

For rPET, this involves collecting used plastic bottles and moving them to recycling centers. This takes energy for vehicles, but the emissions are much lower than getting oil and gas to make new plastic. For RC, this involves collecting textile waste and moving it to recycling facilities. Similarly, this takes energy for transport, but less than needed for farming new cotton across fields and then transporting harvested cotton.

Mechanical vs Chemical Recycling Energy Loads

The energy used in the recycling process itself is a key part of the footprint. Mechanical recycling for cotton uses electricity to power shredding machines. The exact amount depends on the machines and how many times the material is processed. Chemical recycling for both polyester (though less common now) and cotton can require more energy because it often involves heating chemicals and running complex processes to dissolve and make new fibers. The energy source (renewable or fossil fuels) at the recycling facility makes a big difference to the carbon footprint at this stage.

Manufacturing, Dyeing & Finishing Hotspots

After recycling into fiber, both rPET and RC fibers are spun into yarn, knitted or woven into fabric, and then dyed and finished.

• Spinning & Fabric Making: Energy is needed for spinning machines, looms, or knitting machines. This energy use is similar for both rPET and RC fiber, depending on the machinery used.
• Dyeing & Finishing: This stage can be a big source of energy use and also involves chemicals and water. For rPET, dyeing can require high temperatures. For RC, traditional cotton dyeing uses a lot of water and energy. However, color-sorted mechanical recycled cotton can skip the dyeing step, saving a lot of energy, water, and chemical use compared to dyeing new or undyed recycled fibers. Our color-spinning process at regenFabrics, using pre-colored recycled fibers, directly cuts these hotspots.

So, while rPET avoids the high carbon of virgin plastic, and RC avoids the impact of farming, the energy used in the recycling process and the later stages like dyeing are very important for the final "cradle-to-gate" carbon number for both fibers. Choosing color-sorted recycled cotton yarns that skip dyeing offers a significant advantage in reducing emissions at the manufacturing stage.

Beyond CO₂: Water, Chemicals & Microplastics?

Sustainability is more than just carbon. How do recycled polyester and recycled cotton compare on water use, chemicals, and microplastic pollution?

Recycled cotton production uses significantly less water and fewer chemicals compared to virgin cotton farming and processing. Recycled polyester production uses less water than virgin polyester, but microplastic shedding⁴ during washing is a key concern.

While carbon emissions are a key focus, a full picture of sustainability includes other environmental impacts.

Water‑Use & Eutrophication Scores

Water use is a major issue for virgin cotton farming, especially in dry regions. Recycled cotton, because it uses waste instead of growing new plants, drastically cuts water use – often by over 90% compared to virgin cotton. This also means lower impact on water pollution from farm chemicals (eutrophication). Recycled polyester production also uses less water than virgin polyester production, mainly by skipping the steps needed to make the base chemicals from oil. However, the water savings for RC compared to virgin cotton are usually much larger than the water savings for rPET compared to virgin polyester.

Microfibre Shedding vs Biodegradability Trade‑off

This is a big difference between the two fibers. Recycled polyester, like all polyester, is a plastic fiber. When clothes made from rPET are washed, tiny plastic pieces (microfibers or microplastics) can break off and go into the water system. These microplastics do not break down easily in nature and can harm marine life and potentially human health. Recycled cotton, being cotton, is a natural fiber. Cotton fibers can biodegrade (break down naturally) at the end of their life, especially if the fabric is not blended with synthetic fibers or treated with certain finishes. So, rPET has a microplastic problem, while RC is biodegradable. However, RC, especially mechanical recycled cotton, can be less strong and durable than rPET or virgin cotton, which might mean the garment has a shorter lifespan if not blended well.

Durability & Circularity Payback

How long a product lasts matters for its environmental impact. A longer-lasting product means you need to buy fewer new ones. rPET is generally durable and strong, similar to virgin polyester. This means products made from rPET can have a long life, spreading their environmental cost (including recycling) over many uses. Mechanical recycled cotton can have lower durability due to shorter fibers. Blending with rPET or virgin fibers improves this. Chemical recycled cotton aims to match virgin cotton durability. The "circularity payback" is how many times a product needs to be used to make up for the environmental cost of making it. More durable products reach this payback point sooner.

Wear Cycles, Tensile Strength & Product Lifespan

Product lifespan is directly linked to how well the fabric holds up to wear and washing. Tensile strength (how much the yarn can be pulled before breaking) is a key measure of this, as discussed in previous posts. Fabrics with good tensile strength (like those meeting ISO 2062 standards for T-shirts) tend to last longer, giving more wear cycles. rPET typically has good tensile strength. Mechanical RC often has lower strength, but blending (like our TC/CVC with rPET) can improve it greatly, increasing wear cycles and lifespan. Chemical RC aims for strength similar to virgin cotton.

End‑of‑Life Pathways: Closed‑Loop, Downcycling, Compostability

What happens when the product is no longer usable?

• rPET: Can potentially be recycled again into new rPET (closed-loop recycling). However, this is hard to do for blended fabrics (like poly-cotton). More often, rPET textiles are downcycled (used for lower-value products like filling or insulation) or end up in landfills.
• RC: Pure cotton is biodegradable. This is an advantage at end-of-life. However, recycling cotton back into new textile fiber (especially fiber suitable for clothing) is still challenging, particularly for post-consumer waste. Mechanical recycling often leads to downcycling. Chemical recycling offers the most promise for closed-loop cotton recycling. Blends of RC and rPET, like our TC/CVC, are even harder to recycle back into textile fibers currently.

So, rPET has durability and potential closed-loop (bottle-to-fiber) but microplastic issues. RC has water/chemical savings and biodegradability, but mechanical recycling affects durability and closed-loop textile recycling is still developing.

Market Readiness & Cost Drivers?

Recycled polyester and recycled cotton have different levels of availability and different things that affect their price. How do they compare in the market in 2025?

RPET from bottles is widely available globally and generally costs less than recycled cotton. Recycled cotton supply varies by source and quality; chemical RC is newer and more expensive than mechanical RC. MOQs and certification add costs for both.

For brands, choosing a fiber also means looking at if you can get it and how much it costs. In 2025, recycled polyester from bottles (rPET) is much more widely available globally than recycled cotton. The system for collecting plastic bottles is more developed in many parts of the world compared to textile waste collection systems. This higher availability generally makes rPET more stable in price and often less expensive than recycled cotton, especially compared to higher-quality pre-consumer RC or any chemical RC.

Global Capacity & Supply‑Chain Bottlenecks

The capacity to produce rPET fiber from bottles is large and growing. This makes it easier for brands to source rPET yarn in different counts and colors. For recycled cotton, the global capacity is smaller, and the supply chain for getting high-quality cotton waste can have more issues. The availability of specific colors of cotton waste for color sorting also affects supply. Chemical recycling capacity for cotton is still very small in 2025, limiting its availability and making it a specialty product right now.

Price Volatility, MOQ & Certification Fees

The price of rPET is linked to the price of virgin polyester and the cost of collecting and processing plastic bottles. Prices can change based on oil prices and demand for recycled plastic. Recycled cotton prices are more linked to the price of virgin cotton (as a comparison point) and the costs of collecting, sorting, and processing textile waste. Quality and color consistency also affect the price. As we discussed in a previous post, MOQs for recycled cotton yarn, especially custom colors or special blends, can be significant (often 1-2 tons or more). While rPET MOQs also exist, the wider availability might offer more flexibility in some cases. Certification costs (like GRS or RCS) add to the price of both fibers. These costs cover the audits and checks needed to prove the material is recycled and meets standards.

Decision Matrix: When Should Brands Choose Each Fiber?

The choice between rPET and RC is often not just about emissions but about the product needs and sustainability goals.

• High-Performance Sportswear & Workwear: These often need high strength, stretch, and durability. rPET is generally a good choice here due to its natural strength and durability, often blended with spandex. While recycled cotton blends can offer comfort, 100% mechanical RC is usually not suitable for these uses due to lower strength.
• Casual Basics & Low-Impact Capsule Lines: Products like T-shirts, hoodies, and basic sweaters can use recycled cotton effectively. Blends with rPET (like TC/CVC) offer a good balance of sustainability, comfort, and durability. Higher percentages of mechanical RC might work for products with a relaxed fit or a desired texture. For brands focused heavily on avoiding farming impacts, RC is a strong choice. For brands focused on using plastic waste, rPET is key.

Brands need to weigh the performance needs of the product against the specific environmental benefits (carbon, water, microplastics, biodegradability) and market factors (cost, availability, MOQ) of each fiber.

Future Outlook: Emerging Technologies & Policy Signals?

What is coming next for recycled polyester and recycled cotton? New technologies and government rules will shape their future.

Emerging technologies aim to improve textile-to-textile recycling for both polyester and cotton. Policies are increasingly pushing for higher recycling rates and recycled content in products, favoring both fibers but also highlighting challenges like blending.

The future for both recycled polyester and recycled cotton looks promising, driven by ongoing innovation and stronger government action.

Emerging Technologies & Policy Signals

For rPET, the big goal is to move beyond bottle-to-fiber recycling towards textile-to-textile recycling⁵. New chemical recycling technologies⁶ are being developed to break down old polyester textiles (especially blends) back into their basic chemical parts, which can then be used to make new polyester fibers of virgin quality. This is a key area for circularity in polyester. For recycled cotton, chemical recycling technologies are also a major focus. These aim to more effectively process post-consumer cotton waste, including blends, and produce high-quality cotton fiber, enabling true closed-loop cotton recycling. Solving the challenge of separating and recycling mixed-fiber textiles (like cotton-polyester blends) is a critical step for increasing the supply of both recycled cotton and recycled polyester from textile waste. Government policies, like the EU's Ecodesign for Sustainable Products Regulation⁷ (ESPR), are increasingly setting requirements for products to be more durable, repairable, and recyclable. They are also pushing for minimum levels of recycled content in textiles and better systems for collecting textile waste. These policies will create a stronger market demand for both rPET and RC and encourage investment in advanced recycling technologies. While policies favor using recycled content in general, they are also starting to look at issues like microplastics (affecting polyester) and recyclability at end-of-life (affecting blends). The focus is shifting towards ensuring that products are designed for circularity from the start.

FAQs: Fast Answers to PAA Queries?

Getting quick answers is helpful. Here are some fast answers to common questions about recycled polyester and recycled cotton based on what we have discussed.

Recycled polyester (rPET) generally saves more CO₂ than virgin polyester. Recycled cotton (RC) significantly saves water compared to virgin cotton. Both are important for sustainability but have different strengths and challenges in areas like durability and microplastics.

Here are some quick points based on the details we covered:

• Which saves more CO₂? rPET typically shows a larger percentage CO₂ saving compared to its virgin version than RC compared to virgin cotton. However, the starting point matters.
• Are they equally sustainable? They offer different environmental benefits. rPET saves plastic waste and CO₂ (vs virgin poly). RC saves water, land, and chemicals (vs virgin cotton). Both are steps towards sustainability.
• Is recycled cotton weaker? Mechanical recycled cotton can be weaker due to shorter fibers. Chemical recycled cotton aims for virgin strength. Blending with stronger fibers like rPET helps mechanical RC.
• Do they cause microplastics? Recycled polyester (rPET), like all polyester, sheds microplastics when washed. Recycled cotton (RC) is a natural fiber and can biodegrade.
• Can my poly-cotton blend be recycled? Recycling blended fabrics (like TC/CVC) back into new textile fiber is harder than recycling pure fibers, but new chemical recycling technologies are working on this.
• Is recycled cotton GRS certified automatically? No, the entire supply chain must be audited and certified for GRS or RCS claims.

These are quick answers; the details in the sections above provide the full picture for each point.

Conclusion

Choosing between recycled polyester and recycled cotton means weighing their different environmental benefits, performance aspects, and market factors. Both are vital for a sustainable future, offering unique advantages in the journey towards circular textiles.

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