Carpet Tog Ratings & Underfloor Heating Guide

Underfloor heating (UFH) is becoming a standard in new builds and renovations. Many people think this means they can't have carpet. That is a myth.

The Science: Carpets and underlay act as insulators. If they insulate too much, the heat from the floor gets trapped and can't warm the room (and might overheat your system).

The Magic Number: To work efficiently, the combined Tog rating of your carpet and underlay should not exceed 2.5 Tog.

The Carpet: Most carpets have a Tog rating between 1.0 and 2.0. Wool is naturally more insulating (higher Tog) than synthetic. You need to check the spec sheet.

The Underlay: This is where you make the savings. Standard luxury underlay is often 2.5 Tog on its own—too high! You must use a specialized 'Low Tog' or 'Underfloor Heating' underlay, which typically has a rating of 0.8 to 1.0 Tog.

Calculation: Carpet Tog (e.g. 1.2) + Underlay Tog (e.g. 0.8) = 2.0 Tog. This is under the 2.5 limit and perfectly safe.