how to choose sustainable knitwear that won’t pill after one wash

I used to assume that pilling was an unavoidable annoyance — a tiny price to pay for the cosy sweaters I loved. But after years of testing knits, repairing favourites, and swapping tips with makers, I’ve learned that pilling is often predictable and, more importantly, avoidable. Choosing knitwear that won’t pill after one wash is a combination of knowing your fibres, reading construction details, and caring for garments properly. Here’s how I approach it, step by step, when I’m shopping or advising a client.

Understand why pilling happens

Pilling occurs when short or broken fibres work free from the yarn and form little tangles on the surface. Friction — from wearing, rubbing against bags, or washing machines — encourages this process. Some fibres are more pill-prone because they’re shorter and more fragile (think cheap acrylic or low-quality wool). Other factors that influence pilling are the yarn twist, the density of the knit and any surface finishes applied by the maker.

Choose better fibres

When I recommend knits that stand the test of time, I start by looking at the fibre content. Here’s what I usually look for and why:

• Merino wool (mid-to-high grade) — Fine merino can pill if the yarn is loosely spun, but high-quality, tightly spun merino resists pilling and still feels soft. Look for terms like superwash with caution — superwash treatments make wool machine-washable but can sometimes weaken fibres depending on the process.
• Mohair and alpaca blends — Alone these can be fluffy and more pill-prone, but when blended with sturdier wool or nylon they can add softness without creating instant pills. I prefer blends where mohair is used as a halo rather than the main yarn.
• Long-staple cotton — Pima or Egyptian cotton has longer fibres that are less likely to pill than cheaper short-staple cotton. These are great for lighter knitwear and summer sweaters.
• Silk blends — Silk can reduce friction on the surface and looks luxurious. Blends of wool and silk can be less pill-prone than pure wool, depending on yarn quality.
• High-quality cashmere — The best cashmere (grade A, higher micron count, longer fibres) pills far less than cheaper cashmere. If a cashmere jumper is very cheap, expect the fibres to be shorter and more pill-prone.
• Synthetic fibres — Acrylic and low-grade polyesters pill a lot, but modern technical synthetics (used sparingly in blends) can add strength. I avoid pure acrylic and cheap polyester if durability is a priority.

Look for smart yarn construction

Even great fibres can pill if the yarn is poorly constructed. When I’m in-store or reading product descriptions online, I scan for these clues:

• High twist yarns: Yarns that are tightly twisted bind the fibres together, making them less likely to work free.
• Plied yarns: A multi-plied yarn (2-ply, 3-ply, etc.) is generally more robust than single-ply. It handles friction better and pills less.
• Dense knit structures: A tightly knitted fabric keeps fibres locked in place. Open, loosely knit jumpers look airy but will pill sooner.
• Finishes and treatments: Some manufacturers apply anti-pilling finishes. These aren’t a guarantee of permanence, but when combined with good yarn, they help.

Check the garment details

Descriptions and labels reveal a lot. I always read carefully and look for the following in product pages or tags:

• Exact fibre percentages — Avoid vague labels like “wool mix” without details.
• Yarn weight and gauge — Heavy, chunky knits can be durable if densely made; fine-gauge jumpers need high-quality yarns to avoid pilling.
• Care instructions — If something says “hand wash only” but the fibre is low-grade, it might still pill regardless. Prefer garments that come with clear care guidance.
• Origins and brand transparency — Brands that name their mills, yarn types, or include detailed product photography are usually more trustworthy.

Trust reputable, sustainable brands (and what to look for)

I favour brands that emphasise traceability and craftsmanship. A few I’ve had good experiences with include People Tree, Arket, AllSaints (for robust cashmere-blends), and smaller British knitters with transparent sourcing. When a brand lists the grade of cashmere, the origin of wool, or describes yarn construction, it signals they care about quality — which often means less pilling.

Test if possible — and what to ask online

In-store testing is a small ritual for me: I gently rub the fabric between my fingers and check for loose fibres, then inspect seams and cuffs where friction is highest. If I’m shopping online, I’ll look for close-up images and customer reviews mentioning pilling. Ask customer service:

• What is the yarn ply and twist?
• Where is the wool/cashmere sourced from?
• Are any anti-pilling finishes used?

Practical care to prevent pilling

Even the best knit can pill if cared for roughly. I follow these practical tips and teach them to readers and clients:

• Wash less, air more: Many knitwear items only need airing or spot-cleaning. Washing introduces friction.
• Use a gentle cycle or hand-wash: If machine-washing, use a mesh laundry bag, cold water, and a gentle detergent designed for wool or cashmere (e.g., Eucalan or Woolly).
• Dry flat: Don’t tumble dry. Reshape your knit and dry flat on a towel to avoid stretching and surface friction.
• Turn inside out: When washing, turn the garment inside out to protect the surface fibres.
• Store properly: Fold heavy knits rather than hanging them to prevent stretching and rubbing.
• Use a de-piller correctly: A sweater stone, fabric comb, or electric de-piller can refresh a garment. I use them sparingly and gently — aggressive de-pilling removes surface fibres and shortens the life of the knit.

When some pilling is acceptable (and how to handle it)

Pilling is not always the death of a sweater. It’s often surface-level and can be removed. I keep a small fabric comb and a battery de-piller in my kit for quick fixes. If a beloved jumper pills slightly but is otherwise perfect, I de-pill and keep wearing it. That’s sustainable too — repairing and refreshing extend the life of clothes far more effectively than replacing them.

Think repair and re-love

If you do find a pilled area that won’t respond to de-pilling, consider visible mending or reworking: patch with a contrasting knit, add elbow patches, or re-knit small areas. These approaches make a piece unique and keep it in rotation longer.

My quick checklist before buying a knit

Choosing knitwear that won’t pill after one wash is about being curious and selective — not about avoiding natural fibres. With a bit of knowledge and attention, you can build a cosy collection of knits that look newer for longer, feel better on your skin, and sit well with a sustainable wardrobe philosophy. If you'd like, I can outline a capsule of pill-resistant knits for different budgets — from high-street to investment pieces.