Reiff · Winter Sleep Sack
Winter Sleeveless Wearable Blanket
2.5 TOG organic merino wool and cotton sherpa for cold-season sleeping. Full-side zip, German-made, GOTS certified.
Reiff has been crafting organic wool and natural textiles since 1939, when Adolph Reiff founded the company in Gömmingen, Germany. Over three generations, Reiff has evolved from a small baby-wear producer into a global leader in organic wool apparel. Today, under third-generation leadership, Reiff remains committed to ethical production: mulesing-free merino from South America (Patagonia), GOTS-certified organic processing, and nearly all manufacturing within Germany or the EU. Every piece is made to last—designed to be worn through multiple children and passed down.
Winter Sleep Sack for Cold Climates
This Reiff winter wearable blanket is designed for babies and toddlers sleeping in cold homes, cold seasons, and year-round in northern climates. The 2.5 TOG (thermal overall grade) rating makes it ideal for temperatures below 15-21°C (59-69°F). Unlike a lightweight sleep sack, this piece provides substantial warmth without the bulk of a traditional crib blanket—and without the safety risks of loose bedding.
The sleeveless design means it works over layers: wear it over a long-sleeve merino base layer on very cold nights, or over lightweight sleepwear for milder winter days. The full-length side zipper allows diaper changes without removing your child from the bag, making middle-of-the-night changes quick and warm.
Materials & Construction
Exterior: Merino Wool
100% organic merino wool, mid-weight knit. Wool sourced from certified organic, kbT-certified farms in Patagonia (mulesing-free). Knitted to a soft, breathable fabric that regulates temperature naturally.
Lining: Organic Cotton Sherpa
100% organic cotton with soft sherpa pile facing skin. GOTS-certified organic cotton adds softness and breathability to the interior. The sherpa brushing creates a plush, cozy layer without synthetic materials.
Certifications
GOTS (Global Organic Textile Standard) certifies organic fiber farming and the entire processing chain. kbT (kontrolliert biologische Tierhaltung) ensures merino livestock are raised under strict animal welfare and organic farming standards.
Made in Germany
Designed, cut, and sewn in Germany. Reiff has maintained European manufacturing for over 40 years, controlling every step of production quality.
Warmth Level & Temperature Guide
TOG Rating
2.5 TOG
This is a heavy-weight sleep sack, designed for the coldest conditions. TOG measures thermal resistance—higher TOG means more warmth.
Temperature Range
15-21°C (59-69°F)
Best suited for temperatures 59-69°F / 15-21°C. Worn over a long-sleeve base layer on very cold nights, or over light sleepwear in milder winter conditions.
How to use TOG guidance
Room temperature is the key variable. A 2.5 TOG sack works best in cold bedrooms; in warm homes, use a lighter TOG. A good rule of thumb: aim for your child to be warm but not sweating. Merino naturally regulates temperature, so slight over-layering is better than under-warming in winter.
Key Features
Full-Length Side Zip
Open from shoulder to hem on one side, making diaper changes fast and warm—no need to remove your sleeping child from the bag.
Temperature-Regulating Merino
Merino wool naturally absorbs and releases moisture, keeping your child warm without overheating. The fiber is also naturally odor-resistant, so it rarely needs washing.
Safe for Sensitive Skin
Merino at this micron count is soft enough for most babies and toddlers, and especially suitable for eczema-prone or sensitive skin. The organic certification means no synthetic dyes or chemical finishes.
Sleeveless Design
Works as a standalone piece or over layers. On very cold nights, layer a merino long-sleeve top underneath for extra insulation without bulk.
Durable & Lasting
Reiff's construction and fabric weight are designed for years of use and multiple children. These pieces often pass through three or four siblings.
GOTS & kbT Certified
Both certifications verify organic farming, ethical processing, and strict environmental and labor standards. You're supporting responsible textile production.
Sizing & Fit
| EU Size |
Age Range |
Height (cm) |
Height (inches) |
| EU 62–68 |
3–6 months |
62–68 cm |
24–27 in |
| EU 74–80 |
6–12 months |
74–80 cm |
29–31 in |
| EU 86–92 |
1–2 years |
86–92 cm |
34–36 in |
| EU 98–104 |
2–3 years |
98–104 cm |
38–41 in |
| EU 116 |
4–5 years |
116 cm |
45–46 in |
European sizing runs slightly slim
If your child is at the upper end of an age range or tall for their age, size up. The TOG rating and warmth won't change, but you'll have extra length for growth and comfort. A slightly roomy fit is better than a snug one for sleeping.
Honest Assessment
Best For
Babies and toddlers sleeping in cold homes, cold climates, or year-round in northern regions. Ideal for parents who want the warmth and longevity of German-made merino without synthetic insulation or filling. Works especially well for children with eczema or sensitive skin, and for families who keep bedrooms naturally cool (59-69°F).
Trade-Offs
This is a heavy-weight sleep sack designed for cold conditions. If your bedroom is warm or heated, you'll want a lighter TOG rating (1.0 or 2.5 instead). The price is higher than synthetic alternatives—this reflects the cost of certified organic merino, GOTS-certified cotton, German manufacturing, and durability designed to last through multiple children. Wool requires proper care: hand or delicate machine washing in cold water. It's easy once learned, but it's not "throw it in the dryer" simple.
Investment Case
A Reiff sleep sack often outlasts the child wearing it. Many parents pass these pieces to younger siblings, cousins, or friends—not because they wear out, but because the child outgrows it. Merino's natural durability, odor-resistance, and temperature regulation mean it functions beautifully after years and dozens of washes. If you plan to use this sack from newborn through age 4 or 5, or to pass it along, the per-wear cost drops significantly. This is a piece to keep, not to replace seasonally.
Care Instructions
Wash below 30°C Hand or delicate machine cycle Use wool wash detergent Do not bleach Do not tumble dry Dry flat only Lay flat to dry Merino rarely needs washing
Washing: Hand wash in cold water with a wool-specific detergent (such as Eucalan or Sonett wool wash), or use the wool/delicate cycle on your machine with cold water only. Fill the washer no more than half to three-quarters full—wool needs space to move. Do not soak. Press water out gently—never wring or twist. Lay flat on a clean towel to reshape and air dry away from direct heat or sunlight.
Frequency: Merino is naturally odor-resistant and rarely needs frequent washing. Spot-clean visible stains with a damp cloth, or air the sack between uses (outside or in a well-ventilated area). Wash every 5–10 wears, or when soiling requires it. Frequent washing is harder on the fiber than gentle spot-cleaning and airing.
Drying & Storage: Never tumble dry—the heat and agitation will felt and shrink wool. Lay flat to dry on a clean towel, pinning corners if needed to maintain shape. This takes 24–48 hours depending on humidity and air circulation. Store flat or loosely folded in a breathable container; avoid tight, airtight bags. A linen bag or cardboard box works well.
Why this care matters: Wool washed incorrectly (hot water, machine agitation, tumble drying) will felt and shrink irreversibly. Proper cold-water, gentle-cycle washing preserves the fiber's softness, elasticity, and warmth for years. It's simple once you know the rules—and the payoff is a piece that looks and performs like new after years of use.
Frequently Asked Questions
Is merino wool itchy on a baby's skin?
Fine merino at the micron count Reiff uses is soft enough for most babies and sensitive-skinned children. It's meaningfully different from coarse wool. That said, a small percentage of people are sensitive to any wool fiber. If your child has reacted to wool before, start with a wool/silk blend (which is the gentlest option) or test this piece over a light base layer first. The organic cotton lining on this sack helps—baby's skin touches soft cotton on the inside, not just wool.
What's the difference between TOG ratings? Which one do I need?
TOG (thermal overall grade) measures how much warmth a sleep sack provides. A 1.0 TOG sack is light (good for 18–24°C / 64–75°F). A 2.5 TOG is medium-heavy (good for 15–20°C / 59–68°F). A 3.5 TOG (this one) is the warmest (best for below 18°C / 64°F). Choose based on your room temperature: if you keep your bedroom naturally cool or cold, 3.5 TOG is right. If your home is heated to 70°F or warmer, pick a lighter TOG. Merino regulates temperature, so it won't overheat if it's slightly warm—but you want to avoid consistent overheating.
Why is this more expensive than synthetic sleep sacks?
This sack is made from GOTS-certified organic merino wool and cotton (more expensive than conventional), manufactured in Germany (higher labor and environmental standards), designed for multi-year durability and multiple children (not single-season use), and carries no markup for fast fashion or trend cycles. Reiff has maintained 3rd-generation family ownership and European production for over 40 years. The price reflects that commitment. Many families amortize the cost across multiple children or pass it along, making the per-wear cost quite reasonable.
Can I layer this with other pieces, or does it work alone?
Both. On very cold nights, layer a long-sleeve merino base layer underneath, then zip your child into this sack—you've essentially created a 3.5–4 TOG system. On milder winter nights, wear it over lightweight pajamas or a thin cotton sleep layer. The sleeveless design is meant for layering flexibility. You can also wear it alone over medium-weight sleepwear on nights around 15–21°C (59–69°F).
Does the side zip go all the way to the bottom?
Yes—the full-length side zip runs from the shoulder seam to the bottom hem on one side. This makes diaper changes quick without waking your child or removing the sack entirely. The zipper is designed for durability and safety, with no small parts that detach.
How long will this last? Can I pass it to a younger sibling?
Reiff pieces are commonly used by 2–4 children when cared for properly. The merino and cotton are naturally durable; the seams are reinforced; and the weight and construction are built for years. Many families keep these sacks until the fabric visibly degrades—often 5+ years of active use. After your child outgrows the size, wash it gently, lay it flat to dry, and store it in a breathable container. When the next child is ready, it's ready to go.
What if my baby is between sizes? Should I size up?
Yes. European sizing runs slightly slim. If your child is close to the top of a size range or is tall, size up for comfort and to allow for growth. A looser fit is better for sleeping—it allows layers and movement. You won't lose warmth by sizing up; the TOG rating stays the same.
