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How can I keep my baby warm at night without blankets?

Keeping your baby warm at night without using blankets can seem challenging, but is an important part of safe sleep practices. Babies should sleep alone, on their backs, and without any loose or soft bedding like blankets, bumpers, or stuffed animals, according to the American Academy of Pediatrics (AAP). This helps reduce the risk of suffocation, entrapment, and Sudden Infant Death Syndrome (SDS or SIDS). However, without blankets, you may worry about your baby getting cold during the night. There are several effective ways to keep your little one warm and comfortable without compromising their safety.

Use a sleep sack or wearable blanket

Sleep sacks, also called wearable blankets, are a great blanket alternative to keep babies warm at night. They are like little baby-sized sleeping bags that zip up over pajamas. Sleep sacks keep your baby’s chest and arms free while still providing warmth to the body and legs. Most are made from breathable fabrics like cotton or muslin. Some designs have sleeves while others are sleeveless. Many also have options for different levels of insulation based on the thickness of the material. Look for ones with an appropriately high TOG rating for the room temperature. Sleep sacks allow your baby to move freely while preventing kicking off loose blankets. As wearable bedding, they are considered safe for sleep by the AAP.

Types of sleep sacks

  • Swaddle sacks – These are designed to gently restrict movement and soothe newborns who sleep better swaddled. They usually have zip-off wings and can transition to a regular sleep sack when your baby is ready to stop swaddling, around 2-3 months.
  • Sleeveless sacks – These are lightweight for warm weather and help prevent overheating.
  • Short sleeve sacks – For cooler temperatures, short sleeve sacks provide a bit more insulation just on the upper body.
  • Long sleeve sacks – The most insulated style, long sleeve sacks are ideal for colder climates and seasons.

Considerations when choosing a sleep sack

  • Weight – Pick a TOG weight suitable for room temperature. Look for 1.0-2.5 TOG for summer and warmer climates. Choose 2.5-3.5 TOG for cooler temperatures.
  • Neck and arm openings – These should lay flat and not gape open so your baby’s limbs don’t slip inside where the fabric could bunch around their face.
  • Neck closure – A zipper is safest to prevent choking hazards. Avoid sleep sacks with openings that fasten with snaps or buttons at the neck.
  • Hip Healthy – Choose a sack with a design that allows plenty of leg movement to promote healthy hip development.
  • Non-slip – The sleep sack material should have a non-slip texture to keep your baby from sliding down in the crib.

Dress your baby warmly

Babies lose heat quickly from their heads, so be sure to put your baby to sleep wearing warm pajamas and socks under their sleep sack. For colder temperatures, consider:

  • Footed pajamas – Helps keep feet warm and covered.
  • Long sleeves – Provides more insulation for arms versus short sleeves.
  • Extra layers like onesies or sleepers under pajamas – Adds more warmth and thickness.
  • Wearable blankets or buntings over pajamas – Can add an extra layer of insulation.

However, do not overdress your baby or they may get uncomfortably hot and sweaty. A good rule of thumb is to dress your baby in about one more layer than you are currently wearing.

Recommended fabrics

  • Cotton – Breathable and helps absorb sweat if your baby gets hot.
  • Fleece – Provides insulation to maintain body heat.
  • Merino wool – Moisture-wicking, breathable, and thermal regulating. Retains heat when wet.
  • Polyester – Quick drying and holds less moisture than cotton.
  • Silk – Lightweight but very insulating.

Avoid loose fabrics like lace or crochet than can catch on fingers and toes.

Monitor the temperature

Use a room thermometer to help gauge the best sleep sack TOG rating and pajamas needed. Ideal room temperature for safe infant sleep is between 68-72°F (20-22°C). Babies cannot effectively regulate their body temperature, so it’s essential to dress them appropriately for the environment. Signs your baby may be too cold include feeling cool to the touch, red or blue skin, and restlessness. If your baby seems too hot, they may sweat heavily or feel warm and moist. Adjust their clothing layers and room temperature accordingly. You can also place a thermometer inside your baby’s crib to get an exact reading of conditions right where they sleep.

Ideal temperature by age

Age Room Temperature Range
Newborn 72-76°F (22-24°C)
3-6 months 68-72°F (20-22°C)
6-12 months 65-70°F (18-21°C)

Use layers in the crib

There are a few additional layers that can be safely added to your baby’s crib under the fitted sheet that will help them stay warm without loose bedding:

  • Mattress warmer – Electric heating pads made to lie under the crib sheet. Automatically turns off after 1-3 hours.
  • Wool mattress pad – Provides insulation and moisture-wicking.
  • Fleece crib liner – Lines the crib rails and adds warmth.

Avoid products that go between the fitted sheet and mattress since these present a suffocation hazard. Only use mattress warmers with manufacturer instructions stating they are safe for baby sleep.

Keep their head warm

Since babies lose so much heat from their head, keeping their head cozy can help retain overall body warmth. Some options are:

  • Sleep cap – Hats made for sleeping keep the head warm without a safety risk.
  • Hooded pajamas – Built-in hoods help insulate the head.
  • Swaddle hoods – Attach to swaddle blankets to cover the head when swaddling.

Be sure hats and hoods fit securely but not too tightly. Avoid any ties, ribbons, or loose parts which can come undone and pose a strangulation hazard in baby’s sleep environment.

Warm the crib before bedtime

On cold nights, gently heating up your baby’s sleep space an hour before bedtime can keep them cozy longer. You can:

  • Place a hot water bottle in the crib, then remove it before putting your baby down.
  • Turn a crib heating pad on low, then turn off before bedtime.
  • Blow a hairdryer on low setting across the crib mattress to add some warmth.
  • Fill a rubber hot water bottle with warm water, wrap in a small blanket, and place under crib fitted sheet to maintain warmth.

Check that any heating devices raise the crib temperature only slightly so hot spots that could burn your baby are avoided. The crib should feel pleasantly warm, not hot.

Insulate the nursery

Taking steps to retain heat in your baby’s bedroom can help reduce nighttime chill. Try these nursery insulation tips:

  • Add an extra layer of window insulation like insulating cellular shades or plastic film tinting which helps prevent drafts.
  • Make sure all windows and doors seal tightly when shut.
  • Consider installing wall insulation if lacking for older homes.
  • Use area rugs on hardwood or tile to prevent cold from the floor.
  • Maintain a comfortable humidity level of 30-50% to retain heat.

However, do not over-insulate the room or your baby may get too hot. Maintain good ventilation and monitor room temperature.

Use a nightlight

Some studies suggest that nightlights may provide a small amount of heat. Placing a low-watt nightlight near your baby’s crib can minimally warm the nearby air and environment. Opt for an LED bulb that will not burn if touched. As an added benefit, the dim glow may help soothe your little one or make night feedings easier.

Consider safe supplemental heat

If you live in a cold climate or drafty home, supplemental heating may be needed as a backup on extra chilly nights. Some safe options include:

  • Portable space heater – Use an electric model that automatically shuts off if tipped and keep it at least 3 feet from baby’s crib.
  • Humidifier – The steam released can provide subtle warmth to the room. Do not aim vapors directly into the crib.
  • Central heat – Consider bumping up your thermostat at bedtime. But do not allow the room to get too stuffy.

Avoid leaving any heating devices unattended and monitor nursery temperature carefully with these methods.


While you should never use loose blankets in your baby’s sleep space, there are many effective ways to keep your little one warm at night without compromising safety recommendations. Using the right sleep clothing and bedding like sleep sacks combined with monitoring room temperature, safely adding some insulation to the crib, and dressing babies appropriately for the environment can help maintain a warm sleeping space. With the tips above, your baby can sleep comfortably and securely.