Cormar Trinity (1.6 TOG) with Tredaire Ambience (2.37 TOG) gives a combined 2.97 in-situ TOG. Whether that passes the 2.5 TOG underfloor heating limit and what to do.
Updated 05 September 2026.
Cormar Trinity and Tredaire Ambience: combined TOG for underfloor heating
The combined TOG for Cormar Trinity over Tredaire Ambience, 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 Trinity (1.6 TOG) |
|---|---|
| Underlay | Tredaire Ambience (2.37 TOG) |
| Published sum | 3.97 TOG |
| UHMA in-situ correction | minus 1 TOG |
| Combined in-situ TOG | 2.97 TOG |
| Standard UFH limit | 2.5 TOG |
| Heat pump target | under 1.5 TOG |
Cormar Trinity is rated 1.6 TOG and Tredaire Ambience is rated 2.37 TOG. Laid together the combination is what the underfloor heating has to warm through.
The published TOG figures add to 3.97, and even after the UHMA 1 TOG in-situ correction the pair sits at 2.97 TOG, 0.47 TOG over the limit. The carpet is fine; the underlay is doing the damage. Keep Cormar Trinity and drop to a low-TOG underlay such as Duralay Heatflow for Carpet (0.75 TOG) or Duralay Technics 5 (0.56 TOG), which brings the combined figure back into range.
Questions and answers
Cormar Trinity and Tredaire Ambience: combined TOG for underfloor heating?
Combined in-situ TOG is 2.97, above the 2.5 TOG limit, so Cormar Trinity with Tredaire Ambience is not suitable for underfloor heating. Keep the carpet and switch to a low-TOG underlay.