So, what does TOG actually stand for?
TOG stands for 'Thermal Overall Grade'. It is a measure of thermal resistance of a unit of area, also known as thermal insulance. Essentially it is a measurement that can show how much a particular fabric insulates.
Baby sleep bags / wearable blankets are a popular alternative to traditional blankets and sheets and remove the need for additional bedding when sleeping in a cot or similar product.
TOG ratings were introduced in an effort to reduce the incidence of Sudden Infant Death Syndrome, known as SIDS or 'Cot Death'. They are designed to keep children of 4 kg or more at a comfortable temperature through the nights and, as opposed to adult sleeping bags, they are intended for indoor use only.
Baby sleep bags are given a TOG rating according to the warmth they provide.
The higher the TOG value, the greater is the thermal insulation provided.
Whilst a TOG value is directly related to mass per unit area and thickness, the relationship is not linear. It does not therefore follow that an increase in weight or thickness will result in a proportional increase in thermal resistance.
To help parents understand which sleep bag TOG values are right for differing room temperatures, a set of guidelines has been established as per below:
< 1.0 TOG - room temperature 24 °C to 27 °C
1.0 to 2.0 TOG - room temperature 20 °C to 23 °C
2.0 to 3.5 TOG - room temperature 10 °C to 20 °C
The BS 8510 standard describes the TOG test method for baby sleep bags - whose purpose is to ensure that the product prevents babies from overheating during their sleep.
Please note: It is really important that you take into account all external factors when determining which TOG rating sleeping bag should be used. These external factors include but are not limited to: The type and quantity of clothing that the baby has on, the baby's general health and wellbeing, the temperature of the babies bedroom and if this may change throughout the night or day. All these factors may vary in the same way as it does for adults.
It is important to check your baby regularly to ensure that they are comfortable and that they do not overheat.