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How to Choose Your Baby’s Sleep Bag

How to Choose Your Baby’s Sleep Bag

In this post, you'll learn the differences between a baby sleep bag and a swaddle sleep bag, the best sleep bag for your baby based on factors such as TOG and your baby’s age, and how to dress your baby when you use a sleep bag.

As a new parent, you might be wondering how to keep your baby warm at night without using a blanket. While doing your research, you may have come across baby sleep bags (also called sleep sacks). The options for baby sleep bags seem endless. Every baby sleep bag design looks different but also the same.

In this post, we take a closer look at a couple of popular swaddle sleep bag designs and compare them to Nest Designs’ swaddle sleep bags. You’ll also learn the differences between a baby sleep bag and a swaddle sleep bag, the best sleep bag for your baby based on factors such as TOG and your baby’s age, and how to dress your baby when you use a sleep bag. We hope that this post will provide you with a good foundation so you can best decide how to dress your little one for nap time and bedtime. After all, a good night’s rest for your baby means a good night’s rest for you too.

What is a baby sleep bag?

Nest Designs Baby's Sleep Bag

A baby sleep bag (or a baby sleep sack) is a wearable blanket like a sleeping bag for your baby. To keep your baby’s sleep space safe, it is not recommended to use any loose blankets since it is associated with SIDs (Sudden Infant Death Syndrome). A baby sleep bag keeps your baby’s temperature regulated, helps them stay warm and comfortable, and ensures that they’re safe as they sleep at night. 

Why do babies need swaddle sleep bags?

Nest Designs Baby's Sleep Bag

Prenatal nursing classes prepare you for swaddling your newborn, but do you know why? A snug – but not too snug – wrap helps calm them down and makes falling and staying asleep easier. Think of it as replicating the warmth and safety your baby is accustomed to in the womb – familiarity brings security, which makes it easier to relax.

Tiny bubs also have a startle reflex for the first couple of months after birth, causing them to spring awake by flailing their arms unintentionally. A swaddle hugs your baby, keeping them nice and cozy in the same position and preventing the baby from startling themselves awake. 

A swaddle is a wonderful tool for the first few months, one that you’ll appreciate as much as your little one. Between 3 and 6 months is when you’ll want to transition out of swaddles when babies start to roll over.

What to look for in a swaddle sleep bag

Nest Designs Baby's Sleep Bag 

As a parent, you are well aware of how a baby’s sleeping habits affect your own sleep. The more they wake, the more you do too.

A well-researched and thoughtful swaddle sleep bag design actually plays in your favour. Each detail, design element, and fabric choice impact the comfort and safety of this wrap. The right design also helps your child stay asleep with fewer unnecessary interruptions.

Swaddling with or without swaddle sleep bags (using a swaddle blanket) should be done using breathable material that helps regulate your little bubs’ temperature, like cotton and bamboo. 

When shopping for the best swaddle sleep bag for an infant, you’ll want to look at the function and structure of the design, so you understand the value the baby sleep bag offers. 


Nest Designs Baby's Sleep Bag

Swaddle sleep bags for babies are usually made of lightweight, breathable materials like cotton and bamboo. At Nest Designs, we use GOTS certified organic cotton because it is gentler on your baby’s delicate skin and better for the planet. For colder weather, we use Sorona®️ fill to insulate our sleep bags, footed sleep bags, and quilted blankets. Sorona®️ is soft but breathable and dries quickly if it gets wet - helpful for accidents that happen during diaper changes.


Nest Designs Baby's Sleep Bag

Wearable blankets like swaddle sleep bags usually come with a TOG (Thermal Overall Grade) rating. This tells you the warmth of the wearable blanket and how well insulated it is. The higher the TOG rating, the warmer the swaddle sleep bag is. 

Before buying a swaddle sleep bag, you’ll want to consider the following factors to determine the right TOG for your baby: 

  • The temperature of your baby’s nursery.
  • The clothing they’ll be dressed in at nap time/bedtime.
  • Your baby’s overall temperature. 

Nest Designs swaddle sleep bags come in a variety of TOG from 0.25 TOG for the Spring/Summer to 2.5 TOG for the Fall/Winter. 

Read our TOG Guide to learn more about choosing the right TOG rating


Usually, swaddle sleep bags are used until your baby's natural startle reflex disappears. This is usually when your baby is around three to six months old. You’ll find swaddle sleep bags available for newborns to when they're six months of age. 

Types of swaddle sleep bag designs

Design #1: Nest Designs Swaddle Sleep Bag

 Nest Designs Baby's Sleep Bag

The Nest Designs’ Swaddle Sleep Bag incorporates practical construction and cozy materials to grow with your baby and keep them secured while they sleep. Babies can be hugged by the soft fabric with arms down or hands by their faces.

Featuring an uncomplicated design, the Nest Designs sleeping bag is made with a handy two-way zipper for changing, a zipper flap to protect little faces, and detachable swaddle wings that fasten easily with baby-safe Velcro.

Our swaddle sleep bag is versatile and intended to grow with your child. Once little ones start rolling, it’s unsafe for them to sleep in a swaddle. Instead of investing in a new baby sleep bag, parents can remove the swaddle wings, and continue using the sleep bag until their little one outgrows it because of their size (instead of their skill development).

One thing that sets Nest Designs apart is choice and being very upfront with information about our sustainable, quality materials. You may have to hunt around for this information with competitors’ products, or in some cases, you’ll find vague descriptions. We offer our swaddle sleep bags in GOTS certified organic cotton or bamboo, with TOG ratings of 0.25, 0.5, 1.0 and 2.5. Having options ensures little ones are wrapped in a healthy fabric that suits the temperature of the room and climate.  

Design #2: A Sleep Bag with an Attached Swaddle

Nest Designs Swaddle Sleep Bag

Popular in Europe, a leading style of swaddle sleep bag uses a sleeveless sleep bag with an integrated swaddle. With this style, you can wrap your little one three ways, arms by their sides, arms up toward their face, or leave one or both arms free. The baby sleep bag itself is roomy for little legs to move as needed. 

The leading brand in this style uses adjustable swaddle fasteners, an inverted zipper for diaper changes, and a zipper cover for protection. Usually offered in neutral designs and made of 100 percent cotton fabric, this swaddle does the job of keeping little ones comfortable, but only comes in a 1.5 TOG rating.

Design #3: The Wingless Swaddle

Nest Designs Swaddle Sleep Bag

Another recognizable sleep swaddle design is a zipper-free option with a hook and loop closure. What makes this design different is the open bottom for diaper changes. To close off the bottom and keep the swaddle in place, there’s an elastic loop in the lower corner that wraps the swaddle blanket right under the little one’s feet, making them look like they’re sleeping in a giant peapod. 

The most well-known makers of this design use moisture-wicking fabric with a 0.8 TOG rating. These are built to grow with little ones, using a staggered loop design on the right side to accommodate growing babies.

Which sleep bag to choose based on age

Nest Designs Baby's Sleep Bag

Finding the best sleep bag for your baby depends on how old they are. At Nest Designs, we believe that there is no one-size-fits-all approach for safe and comfy sleep. That’s why we designed the Nest Designs Sleep System that considers your bubs’ age, what they’re doing developmentally, and what will keep them safe as they sleep at night.

During the fourth trimester when your bubs is a newborn to about six months, you’ll want to use either a swaddle sleep bag or a startle stop sleep bag. 

Nest Designs Baby's Sleep Bag

After the newborn phase, your bubs will start to move and will never want to stop. This happens between three to six months when they outgrow their startle reflex. At this point, you’ll need to stop swaddling them to keep them safe. You can keep your bubs safe and cozy at night with a sleep bag. We’ve designed ours with short sleeves, long sleeves, and removable sleeves! 

Once your bubs starts walking, climbing, and even running, a sleep bag can become a tripping hazard. That’s when Nest Designs footed sleep bags (previously called sleep suits) come in! These are wearable blankets but with leg holes for your bubs’ little feet so they can move safely. 

Once your bubs reach big kid status, they’ll outgrow wearable blankets and can move onto a regular blanket like our quilted blankets

What should a baby wear under a sleep bag

Nest Designs Baby's Sleep Bag

A question we often get from parents is, “What should my baby wear under their sleep bag?”. Remember, babies cannot regulate their temperatures as well as adults. A general rule of thumb is to dress your baby in one extra layer than what you’d be comfortable with wearing. 

This could be a onesie, footed PJs, or footless PJs under their sleep bag. How you dress your baby will depend on the TOG (Thermal Overall Grade) of the sleep bag, the temperature of our child’s room, and your little one’s overall temperature. 

Baby Sleep Bags for the Win

A well-rested baby means well-rested parents. The right baby sleep bag or sleep sack will keep your little one cozy and content for their nap and throughout the night. Choosing the right one will depend on factors such as how old your bubs is, your baby’s nursery temperature, and what you’re dressing your baby in under their sleep bag. 

Get a good night’s rest and dress your bubs’ in one of our swaddle sleep bags, sleep bags, or footed sleep bags