Baby Sleep Sacks & Sleep Bags

Match TOG to room temperature, not to age or season. 0.5 TOG for 75–81°F. 1.0 TOG for 69–75°F. 2.5 TOG for 61–68°F. A nursery thermometer is the simplest investment in better sleep most households will make.

Sleep sacks (wearable blankets) are the AAP-preferred alternative to loose bedding in the crib. For newborns specifically, most families start in a swaddle and transition to a sleep sack with arms free at 8–16 weeks, when the baby shows signs of rolling. A correctly-sized sleep sack — snug at the shoulders, not loose at the neck — is safe for newborns once the arms-in swaddle phase ends.

Most families switch to a sleepsuit (separated legs) around 12–15 months, when the baby is walking confidently in the crib. The closed-leg sleep bag becomes a trip hazard at that point. Some children stay in sleepsuits through age 2–3; others transition to pajamas alone. There is no fixed age — the cue is mobility and the household's nursery temperature.

For sleep bags that get washed weekly, yes. Bamboo rayon is softer at first wash. TENCEL™ Lyocell is the same on the fiftieth wash. The fiber holds up to repeated laundering with less pilling and less thinning. For the 0.5 TOG muslin format, we use Tanboocel viscose-from-bamboo, which is a third-party-verified production process that's a step beyond generic bamboo viscose.

The under-layer fine-tunes the warmth math the sleep bag does. Short-sleeve bodysuit at the top of each TOG temperature band, long-sleeve in the middle, sleeper at the bottom. For a 1.0 TOG bag in a 72°F nursery, a long-sleeve TENCEL™ sleeper is the right pairing.