Baby Sleep Sacks & Swaddles: TOG Ratings Explained & Seasonal Cost Comparison

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The American Academy of Pediatrics Safe Sleep Guidelines strictly advise against loose blankets, quilts, or pillows in an infant's sleep space due to the risk of SIDS and suffocation. Wearable blankets and sleep sacks have become the universally recommended alternative to keep infants warm and comfortable throughout the night.

However, understanding TOG ratings (Thermal Overall Grade) and sizing transitions can be confusing for new parents. Here is our scientific temperature guide and product comparison.

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1. Nursery Temperature & TOG Rating Chart

Nursery Room Temp	Recommended TOG Rating	Layering Guide Beneath Sleep Sack
75°F – 80°F+ (24°C+)	0.5 TOG (Ultra-light cotton/bamboo)	Short-sleeve onesie or diaper only
69°F – 74°F (21°C – 23°C)	1.0 TOG (Standard all-season cotton)	Long-sleeve cotton footie pajamas
61°F – 68°F (16°C – 20°C)	2.5 TOG (Padded winter fleece/quilted)	Long-sleeve onesie + footie pajamas
Variable 64°F – 75°F	Woolino Merino Wool (Microclimate thermoregulating)	Standard cotton pajamas year-round

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2. The One-and-Done vs Size-by-Size Economics

• Standard Cotton Sacks (Halo / Kyte Baby): Cost $24 to $38 per sack. Because babies require multiple sizes (Small, Medium, Large) across multiple seasons (0.5 TOG summer, 2.5 TOG winter), a parent typically purchases 6 to 8 sacks over two years (~$180 – $260 total).
• Woolino 4-Season Merino Wool Sleep Bag: Retails for $109. Sized from 2 months to 24 months in a single universal garment with natural temperature-regulating Australian merino wool. While the upfront price tag is steep, buying two Woolino sacks ($218 total) covers all four seasons for two full years with zero size obsolescence.