Cormar Primo Plus TOG value and underfloor heating
The published Cormar TOG value for Cormar Primo Plus and the underlay budget it leaves over a heated floor.
Leaves 1.4 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.
| Range | Cormar Primo Plus |
|---|---|
| Construction | polypropylene twist |
| TOG rating | 1.1 TOG |
| Max underlay TOG for UFH | 2.4 TOG |
Cormar Primo Plus is a polypropylene twist with a published TOG value of 1.1. A hard-wearing Primo twist rated 1.1 TOG, low enough for most underfloor-heating underlays.
Using the UHMA rule, in-situ resistance is carpet plus underlay minus 1. To keep Cormar Primo Plus under the 2.5 TOG limit the underlay must be no more than 2.4 TOG.
TOG measures thermal resistance, so a low number means heat passes through easily. For a floor covering over underfloor heating that is what you want. A comfort underlay chosen for warmth underfoot does the opposite job and is the usual reason a heated floor underperforms after a carpet goes down.
Sources: Cormar Carpets published carpet TOG values · UHMA guidance on underfloor heating with carpet and underlay (combined-TOG rule)