Cormar Sensation Original and Duralay Durafit 650: combined TOG for underfloor heating
The combined TOG for Cormar Sensation Original over Duralay Durafit 650, worked against the UHMA underfloor heating rule.
Combined against the UHMA 2.5 TOG underfloor-heating limit. Under 1.5 also suits a low-temperature heat pump.
| Carpet | Cormar Sensation Original (1.7 TOG) |
|---|---|
| Underlay | Duralay Durafit 650 (1.1 TOG) |
| Published sum | 2.8 TOG |
| UHMA in-situ correction | minus 1 TOG |
| Combined in-situ TOG | 1.8 TOG |
| Standard UFH limit | 2.5 TOG |
| Heat pump target | under 1.5 TOG |
Cormar Sensation Original is rated 1.7 TOG and Duralay Durafit 650 is rated 1.1 TOG. Laid together the combination is what the underfloor heating has to warm through.
The published TOG figures add to 2.8. The UHMA rule subtracts 1 TOG because tests showed real in-situ resistance runs about a TOG below the paper sum, giving 1.8 TOG. On a heat pump running low flow temperatures the floor has less heat to push, so aim under 1.5 TOG and prefer the thinnest underlay in this range.
Sources: UHMA guidance on underfloor heating with carpet and underlay (combined-TOG rule) · How to calculate a combined TOG (UHMA formula, worked) · Cormar Carpets published carpet TOG values · Interfloor / Duralay Durafit 650 underlay datasheet