A wool rug on underfloor heating
Rug, underlay and parquet add up above underfloor heating. What manufacturers and laying rules say, and what to check before a project.
Can a wool rug be laid on underfloor heating? Yes, on one condition: that all the layers placed on the floor, floor covering, underlay and rug, remain below the thermal resistance allowed by the floor's manufacturer and by the heating installer. For a rug insulates, and the underlay adds to the rug. For carpet, the British maker Cormar recommends, drawing on research by the UK underfloor heating manufacturers' association, a combined value for the covering and its underlay of less than 2.5 tog. Some parquet instructions in France go further: Panaget's, for laying on heated floors, limits the combined thermal resistance of coverings to 0.13 m².K/W and prohibits rugs and low furniture. The answer therefore depends less on the rug than on the floor on which it is laid.
What thermal resistance measures
Thermal resistance says how much a layer slows the passage of heat. In France, it is expressed in m².K/W; in the United Kingdom, carpet makers readily speak in tog. The higher the value, the more the layer insulates. Underfloor heating spreads its heat through the surface of the floor: everything placed on it retains a share, and each layer adds to the others.
The rules do not all concern the same object. Cormar speaks of carpet, glued or stretched across the whole room. Panaget speaks of rugs and low furniture placed on a parquet: in both cases, it is a matter of what covers the floor and retains a share of its heat.
An underlay enters the calculation just as the rug does. Its material and thickness are therefore chosen with the heating in mind, as explained in our guide to the underlay.
The floor decides as much as the rug
Panaget's laying sheet recalls that, under basic conditions, the surface temperature of a finished floor must not exceed 28 °C. It refers to the texts governing underfloor heating in France: DTU 65.14 for hot-water systems, standard NF P 52-302 for electric cables embedded in concrete, and the CSTB technical specifications for electric radiant floors. The manufacturer warns that a rug can greatly reduce the system's performance and damage the parquet.
From one manufacturer to another, the thresholds change. The instructions for the floor covering, whether parquet, tiles or concrete, are the first document to read. The heating installer is the second point of contact, because he knows the power and setting of the system.
In a project, the question is settled before laying
For an architect or a decorator, the rug enters the floor calculation from the design stage. The format, the thickness of the pile and the underlay are decided at the same time as the covering, rather than once the site has been handed over. Our rugs hand-knotted in Nepal and hand-tufted in India do not have the same construction: the page on hand-knotting and the page on hand-tufting give their characteristics. For a specific place, our Studio, devoted to the projects of architects and decorators, is the point of contact for these exchanges.
Heat passes, or it does not. It is a matter of values, and these values are written in the floor's instructions.
Text written by the house of Diacasan Edition, Parisian publisher of artists' rugs, from the manufacturers' instructions and laying rules cited below, for the projects carried out with our architect and decorator clients, October 2026.
Sources: Cormar Carpets, Tog values; Panaget, laying sheet for heated floors (April 2024).
Questions fréquentes
Does a rug damage underfloor heating?
It can harm the system and the covering. The laying sheet of the parquet maker Panaget warns that a rug can greatly reduce the performance of a heated floor and damage the parquet, and it prohibits rugs and low furniture on its heated parquets. Other manufacturers allow a textile covering below a thermal resistance threshold. The applicable rule is that of your floor's instructions, to be confirmed with the heating installer before laying the rug.
What rug thickness on a heated floor?
There is no single thickness: what counts is the total thermal resistance of the layers placed on the floor. For carpet, the British maker Cormar recommends a combined value, covering and underlay, of less than 2.5 tog. A French parquet such as Panaget's limits the combined resistance of its coverings to 0.13 m².K/W. The thicker the rug and its underlay, the more they count in this total.
What surface temperature for underfloor heating?
Under basic conditions, the surface temperature of a finished floor must not exceed 28 °C, recalls Panaget's laying sheet, which refers to DTU 65.14 for hot-water underfloor heating. This limit applies to the floor, with or without a rug. A rug retains a share of the heat, which explains why some manufacturers regulate or prohibit its use. The installer knows the precise setting of your system.
Can an underlay be used on a heated floor?
Yes, if its thermal resistance is counted with that of the rug. An underlay also slows the heat, and manufacturers' recommendations concern the combined value of all the layers. Thin models limit this effect. Before laying, one must check the floor's instructions and the installer's advice, then choose the rug and its underlay together.