September 15, 2026
Sleeping bagsTOG: choosing the sleeping bag for the coldest hour of the night
You dress the child at nine in the evening, with the room still warm from the day. They will be sleeping there until seven in the morning, and by five the room is three or four degrees colder. The bag's TOG must account for that time, not the time you put them to bed.
The room cools down while they sleep
An unheated room loses heat all night long and reaches its minimum just before sunrise. This is why the same bag that seemed right at bedtime feels insufficient in the early hours, when no one is awake to add an extra layer.
Example drawn to scale to show the shape of the curve. The degrees in your home depend on insulation, orientation, and heating.
Set the thermometer to the coldest hour
Drag the marker to the degrees the room reaches in the early morning. The recipe on the side changes with it.
Drag the thermometer
With 18 degrees in the room
- Underneath
- Long-sleeved pajamas.
- Design
- With or without sleeves, depending on whether they uncover their arms.
- In store
- Molis&Co 2.5 TOG Misty Rose
The recommended range for a sleeping baby is 16 to 20 degrees, which is the green mark on the thermometer. Below that, you increase the TOG and the clothing underneath, never the number of bags.
- Never use two sleeping bags on top of each other, regardless of how cold it is.
- Nothing loose in the crib: pillows, duvets, crib bumpers, positioners, and heavy bedding must be kept out.
- The neck opening must be snug so the child cannot slip inside the bag.
- Check by placing your hand on the nape of the neck or chest. Hot or sweaty skin means one layer too many. Cold hands and feet to the touch are normal.
The same number, three designs
The TOG printed on the label measures the bag's fabric. What it doesn't know is how much skin is left uncovered, and that changes the result as much as half a TOG point.
Where the number comes from
The TOG is a unit of thermal resistance, invented in 1946 by two physicists at the Shirley Institute in Manchester. One TOG equals 0.1 m²·K/W: with one watt of heat passing through each square meter, the fabric maintains a 0.1-degree difference between the inside and the outside. The scale is linear, so a 2.5 resists five times more than a 0.5.
The Lullaby Trust refuses to publish an exact TOG-to-degree match because materials and underclothing change the result. The ranges here are an honest starting point, and the confirmation is always a hand on the back of the neck.
Size counts just as much as TOG
A bag that is too big allows the child to slip inside. That is why sizes are given in centimeters of height: at Molis&Co, the categories range from 56 to 70 cm, 70 to 80 cm, 80 to 90 cm, 90 to 100 cm, and 100 to 110 cm, and at Lässig, models with legs cover 1-2 years and 2-3 years. Measure from shoulder to feet and choose the range they currently fit into.
What we have in stock, by category
Prices are as of the date of this article.
On order
Molis&Co 0.5 TOG, Ballons
Sleeveless and without socks, for rooms above 24 degrees.
€27.9560 to 110 cm
In stock
Molis&Co 1.0 TOG, Teddy
With snap-on sleeves and socks. The most used category of the year, from 20 to 24 degrees.
€42.9560 to 110 cm
In stock
Molis&Co 2.5 TOG, Misty Rose
With feet and sleeves, for those already walking and for rooms at the bottom of the range.
€44.9560 to 110 cm
In stock
Lässig 2.5 TOG with legs, Milky
Separate legs instead of a closed bag, for those who get up on their own at night.
€69.001 to 3 yearsIn our store, the warmest we carry is 2.5 TOG. If your room is below 16 degrees for a good part of the night, the conversation should start with heating and underclothing before looking for a thicker bag.
Don't buy in the dark.
Tell us the child's height and the room temperature, and we will choose the right TOG and design with you.
See the sleeping bags Talk to usAnd at your home, how many degrees does the room thermometer read at five in the morning? If you have never measured it, that is where the choice begins.
Sources: The Lullaby Trust, How to dress your baby for sleep, for the 16 to 20-degree range, underclothing, and what stays out of the crib. Definition of TOG: F. T. Peirce and W. H. Rees, Shirley Institute, 1946, 1 TOG = 0.1 m²·K/W. Prices, stock, and designs verified on gotu.pt on September 15, 2026.