The simplest way to explain it is this - a TOG rating is used for measuring the warmth levels of duvets and baby sleeping bags. The higher the number, the warmer it will be and the lower the number, the cooler or lighter it will be.
TOG stands for Thermal Overall Grade, and in more technical terms is used to measure the thermal resistance of a unit area (also known as thermal insulance). It is commonly used in the textile industry and was developed in the UK to explain warmth levels of duvets (doonas).
It is interesting to note, that in the UK, a Summer duvet is rated as between 3.0 - 4.5 TOG, while a duvet used for Spring/Fall is rated between 7.5 - 10.5 TOG, and a Winter duvet is rated between 12.0 - 13.5 TOG (wow, that's pretty high right).
So think about these numbers in the context of duvets used by adults or older children. Granted it is assumed that there are no other factors being considered, like room temperature or clothing used in bed.
For Babies however, please note: There are a number of other factors that should be considered when determining what TOG rating sleeping bag you should use for your baby. These include the clothing your baby is wearing, the room temperature of your baby's room, your baby’s health and other bedding/blankets you will be using.
And always check your baby regularly to ensure they do not overheat.
All our sleep sacks and sleep suits are TOG tested by by Bureau Veritas UK and have passed British Standard 8510: 2009 Clause 7 (Thermal Resistance) and we choose to use only natural fibres like cotton as this helps with thermal regulation by offering breathability and prevents sweating, which can cause fluctuations in temperature in the night.
Our sleep sacks are tested by Bureau Veritas UK and have passed British Standard 8510: 2009 Clause 7 (Thermal Resistance) and are TOG rated a follows:
SUMMER | 0.4 TOG - suitable for extreme hot Summer temperatures
ALL SEASONS | 0.7 TOG - suitable for all seasons (with appropriate clothing and bedding)
WINTER | 2.0 TOG - suitable for the colder Winter season
Figuring out which TOG rating to use
To figure out which TOG rating sleeping bag is right for your baby, you first need to determine the temperature of your baby’s room.
Many sleep experts recommend a room temperature between 68Fº - 72Fº is best for a baby's nursery.
Once you know your baby's room temperature, you can use the chart below to work out which TOG rating sleep bag and sleep clothing is appropriate for your baby. There are few things to keep in mind:
A baby sleeping bag surrounds the baby, providing insulation from both below and above, and also a warm pocket of air around the baby. This is the reason why the TOG rating for a baby sleeping bag is much lower than adult donnas (duvets). While adult donnas (duvets) may seem more thick and warm, it is recommended that baby’s sleeping bag be kept 'light weight' and should never be more than 3.5 TOG rating.
Layering your baby's sleep clothing underneath a sleeping bag allows greater flexibility in keeping babies warm and cozy without overheating. Keep in mind that each additional layer of clothing adds to overall TOG rating. Too many layers can result in overheating and may increase the risk of sudden infant death syndrome (SIDS) in babies.
Thicker fabrics does not equal more warmth - TOG measures how well a garment retains heat. Just because two fabrics feel the same, it doesn't mean both fabrics retain heat the same way. It all depends on the composition of the fabric as well as the layers and the fillings that make up the garment. That's why TOG rating is tested in a lab to show how well a fabric can retain heat.
How to dress your baby with a TOG rated sleep sack
It's important to use the TOG rating and suggested clothing only as a general guide.
Just like adults feel the temperature differently, your baby will too. For example, you might be fine with a sweater in 60°F degrees weather whereas someone else might be bundled up in a jacket on top of a sweater.
Your baby is your best gauge
Always check your baby regularly to ensure they do not overheat or are too cold.
Watch how your baby reacts to different TOG ratings to ensure your baby is warm or cool enough for sleeping. Here are some things to watch out for when dressing your baby for sleep:
Watch for signs of overheating:If your baby has damp hair, sweaty backs and chest, red ears, fevers, your baby may be too hot and needs to be dressed down. Take off a layer or use a sleep bag with a lower TOG rating.
Frequent wake-ups:If your baby is waking up crying or fussing, it may be a sign that your baby may be too hot or cold, or itmay be due toother developmental reasons (i.e. teething, growth spurt, dropping naps, etc). If your baby feels cold to the touch (back of the neck or chest/back) then add a layer or put on a higher TOG rating sleeping bag.