The simplest way to explain it is this - a TOG rating is used for measuring the warmth levels of doonas (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 doonas (duvets).
It is interesting to note, that in the UK, a Summer doona is rated as between 3.0-4.5 TOG, while a doona used for Spring/Autumn is rated between 7.5-10.5 TOG, and a Winter doona is rated between 12.0-13.5 TOG (wow, that's pretty high right).
So think about these numbers in the context of doonas 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,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 wearingunderneath the sleep bag, the room temperature of your baby's room, your baby’s health and other bedding/blankets you will be using.
TOG rating is not a mandatory testing requirement in Australia. However, we appreciate that the TOG rating system is widely understood by our customers as an indicator of warmth, and so we at Baby Loves Sleep have all our sleep bags and sleep suits tested by an accredited testing lab to determine the TOG ratings for our seasonal sleep bag and sleep suit range. We ensure our products stay true to the actual TOG rating test result which is the reason why our TOG ratings don't fall exactly as 0.5, 1.0, 2.5.
In addition, we choose to use only natural fibres such as Cotton which helps thermal regulation and is 100% breathable, prevents sweating, and reduces fluctuations in temperature in the night.
All Baby Loves Sleep sleep bags and sleep suits are TOG tested by Bureau Veritas UK and have passed British Standard 8510: 2009 Clause 7 (Thermal Resistance) and offer the following TOG ratings:
SUMMER 'Cool' | 0.4 TOG - an ultra light and breathable material that is best suited for extreme hot Summer temperatures and for homes where there may not be air conditioning or cool air.
ALL SEASONS | 0.7 TOG - suitable for all seasons (with appropriate clothing and bedding), best suited for baby's nursery that tend to stay moderate and comfortable or for homes where the air is conditioned by a heater or fan. Ideal for most climates, most of the year around, and where baby's nurseries are recommended to be kept between 18-22 °C.
WINTER 'Warm' | 2.0 TOG& 2.5 TOG - suitable for the colder Winter season (with appropriate clothing and bedding),andfor homes that don't have much heating in the room, suitable for chilly weather, and where baby's nurseries can fall below 18 °C.
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 18-22 °C be kept.
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 bag
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 jumper in 16°C degrees weather whereas someone else might be bundled up in a jacket on top of a jumper.
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.