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TOG Rating Guide

The word Tog is thrown around a lot in textile related industries, but the precise meaning and usage of the word is still a mystery to many people. If you can’t currently make an informed choice between high or low tog underlay, or want to understand the specific attributes of the flooring selection that you have made, this article is perfect for you!

What is a tog?

A tog is a unit of measurement for the thermal resistance of a material, originally developed by the  Shirley Institute. Put simply, the higher a material’s tog rating, the more heat that it will retain, and the better it will be as an insulating material. A material with a high tog value would make an excellent winter coat, as it would retain a large proportion of your body’s heat while wearing it, while a coat manufactured from a low tog rated material would be better suited for use in warmer seasons, as it would allow a far greater amount of your body’s heat to radiate away while being worn.

In more  technical terms, a tog equates to ten times the temperature difference, measured in °C, between two surfaces of a given material, when the flow of heat is equal to one watt per square meter. Therefore, in the case of a flooring underlay, the tog rating refers to the difference in temperature between the top and bottom layers.

Why is tog rating important in the selection of flooring?

As a measurement of the insulation and heat resistant properties of a particular material, it should be clear at this point that tog ratings have a large impact on the decision of which flooring material should be chose in a particular situation, depending on the area of floor to be covered, the environmental conditions of the building in which the the flooring in question is situated, and the personal preference of the property’s resident. 

There are two main choices when it comes to tog rating in regards to flooring underlay and material, with said choices revolving around budget, and whether underfloor heating is present. Underfloor heating requires low tog rated underlay and flooring material, to ensure that as much heat as possible makes it into the room above; maximising the comfort of residents, and minimising energy costs. 

Conversely, optimum comfort for residents without underfloor heating is best achieved through the use of high tog rated underlay and flooring material, ensuring that minimal heat is able to leech through flooring and away from the room, therefore minimising wasted energy. The final choice of flooring material will obviously be made in regards to budget as much as any other practical considerations; but the closer you can get to the optimum tog rating for your needs, within the budget you have set for yourself, the better value for money you will have received!

In general, this means that wooden flooring, some varieties of vinyl flooring, and thin carpeting are most useful as a flooring option if underfloor heating is used, while thicker carpeting and vinyl provide optimum insulation for rooms or buildings that lack such a feature, and which are particularly susceptible to cold.