Wool care has a reputation for being complicated. It isn't - but it does require understanding two things that matter and ignoring the rest: temperature and agitation. Get those right, and a merino wool garment will hold its shape, softness, and performance through years of washing.

This guide covers how often to wash wool, machine vs hand washing, drying, pilling, and the environmental case for washing less.

How Often Should You Wash Wool?

Less often than you think - and significantly less often than synthetic garments.

Merino wool is naturally:

- Odour-resistant - its antimicrobial properties prevent the bacterial growth that causes odour in synthetic fibres, meaning it can be worn multiple times between washes without developing smell

- Moisture-wicking - it moves moisture away from skin and releases it into the air, keeping the garment dry rather than retaining sweat

- Stain-resistant - lanolin, the natural wax coating on wool fibres, causes liquids to bead on the surface rather than absorb immediately

- Self-refreshing - airing a merino garment outside for a few hours is sufficient to remove most odour and restore freshness between washes

In practical terms: merino base layers and everyday garments typically need washing every three to five wears under normal conditions. Light outdoor layers can go longer. Trust your nose over a schedule.

This matters environmentally as well as practically. Every wash cycle a synthetic garment goes through releases approximately 700,000 microplastic fibres into wastewater - fibres that pass through most treatment systems and enter waterways and oceans. Merino fibres are biodegradable and do not produce persistent microplastic pollution. Washing merino less frequently compounds that advantage. 

Before You Wash: Check the Care Label

Every Nui garment carries a care label specific to that product. Read it before washing - care requirements vary between product types, and the label supersedes any general guidance.

As a general rule:

- Merino thermals, merino silk, and most non-knit garments - machine washable on a gentle or wool cycle at or below 40°C

- Merino knits - hand wash only

Machine Washing Wool: What You Need to Know

The critical variable is water temperature.

Wool felts - shrinks irreversibly - when exposed to heat combined with agitation. The threshold is approximately 40°C. Most washing machines labelled "cold wash" still introduce some warm water to dissolve detergent, which means a cycle nominally set to cold may run warmer than expected.

To machine wash merino safely:

- Use the wool or delicate cycle - these use reduced agitation and slower spin speeds designed to protect natural fibres

- Set water temperature to 40°C maximum - cooler is better

- Use a mild, natural detergent - avoid enzyme-based detergents, which can break down protein fibres including wool and silk

- Turn garments inside out to reduce surface friction and minimise pilling

- Do not use fabric softener - it coats wool fibres and reduces their natural moisture-management and odour-resistance properties

- Use a mesh laundry bag for additional protection against agitation

What to avoid:

- Bleach or optical brighteners - these damage wool fibre structure

- High spin speeds - these cause felting and distortion

- Tumble drying - heat causes irreversible shrinkage

Hand Washing Wool: Step by Step

Hand washing is the recommended method for all wool fully fashioned knits and the preferred method for any merino garment where longevity is the priority.

Step 1: Fill a basin or sink with cool to lukewarm water - maximum 40°C. Do not use hot water.

Step 2: Add a small amount of mild wool detergent and allow it to dissolve fully before adding the garment.

Step 3: Submerge the garment and gently press it through the water. Do not rub, wring, or twist - these actions cause felting and distortion.

Step 4: Allow to soak for up to 10 minutes if needed.

Step 5: Drain and refill with clean cool water. Gently press the garment to rinse - repeat until water runs clear.

Step 6: To remove water, gently press the garment against the side of the basin. Do not wring. Lay it flat on a clean dry towel, roll the towel around the garment, and press firmly to absorb excess moisture.

Drying Wool: Always Flat, Never Hot

Lay flat to dry - this is non-negotiable for knits and strongly recommended for all wool garments.

Hanging wet wool causes the weight of water to stretch the garment out of shape, particularly at shoulders. Tumble drying causes heat-induced shrinkage. Neither is recoverable.

How to dry wool correctly:

- Reshape the garment gently while still wet - this is the point at which it can be eased back into its correct dimensions

- Lay flat on a clean dry towel, a white towel (colours can transfer to wet wool), or a purpose-made garment drying screen

- Dry away from direct sunlight, direct heat sources, or radiators - these cause uneven drying and can yellow wool

- Allow to dry fully before folding or storing - wool stored slightly damp is susceptible to mildew

On tumble drying: avoid it entirely for wool. Even a low-heat or air-only cycle introduces enough agitation to cause progressive felting over time.

The environmental case for skipping the dryer applies to all your laundry: air drying clothing for six months of the year eliminates approximately 700 pounds of CO2 emissions annually per household.

How to Deal With Pilling

Pilling - the small fibre balls that form on wool garment surfaces - is a normal characteristic of short-staple natural fibres and is not a sign of poor quality. It occurs when short fibres migrate to the surface through friction during wear and washing, then tangle together.

Pilling typically reduces after the first few washes as the short fibres work their way out. It can be removed cleanly with a fabric comb or electric fabric shaver - tools designed to lift and trim pills without damaging the underlying weave.

To minimise pilling:

- Turn garments inside out before washing

- Use the delicate or wool cycle with low agitation

- Wash similar weights together - heavy garments abrading lighter ones accelerates pilling

- Use a mesh laundry bag

Dry Cleaning Wool: When and How

Nui garments are designed to not require dry cleaning. If you do use a professional cleaner, specify wet cleaning or liquid CO2 cleaning rather than conventional dry cleaning.

The primary solvent in conventional dry cleaning - perchloroethylene (PERC) - is classified as a probable human carcinogen, linked to liver and kidney damage with repeated exposure, and is a significant groundwater contaminant. Wet cleaning uses water as the primary solvent and is appropriate for most wool garments. It substantially reduces both toxicity and the CO2 footprint of garment care.

Washing Synthetic Garments: Reducing the Damage

If your wardrobe includes synthetic garments, the following practices reduce microplastic release during washing:

- Wash less frequently and only when genuinely needed

- Use a microfibre-catching laundry bag (such as a Guppyfriend bag) - these capture a portion of shed fibres before they enter wastewater

- Wash on cold, short cycles with low agitation - heat and friction increase fibre shedding

- Wash full loads - less inter-garment friction means less shedding

- Skip the dryer - tumble drying significantly increases fibre shedding compared to air drying

These are partial measures. The most effective reduction in microplastic laundry pollution is replacing synthetic garments with natural fibre alternatives over time - not because perfection is the goal, but because each substitution permanently removes a source of ongoing pollution from your household. 

Wool Care Summary

Care instructions for every Nui garment are on the product page and care label. Explore the merino collection - made to last, easy to care for.