Cormar Silken Serenity (1.5 TOG) with Tredaire Brio (2.18 TOG) gives a combined 2.68 in-situ TOG. Whether that passes the 2.5 TOG underfloor heating limit and what to do.
Updated 05 September 2026.
Cormar Silken Serenity and Tredaire Brio: combined TOG for underfloor heating
The combined TOG for Cormar Silken Serenity over Tredaire Brio, 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 Silken Serenity (1.5 TOG) |
|---|---|
| Underlay | Tredaire Brio (2.18 TOG) |
| Published sum | 3.68 TOG |
| UHMA in-situ correction | minus 1 TOG |
| Combined in-situ TOG | 2.68 TOG |
| Standard UFH limit | 2.5 TOG |
| Heat pump target | under 1.5 TOG |
Cormar Silken Serenity is rated 1.5 TOG and Tredaire Brio is rated 2.18 TOG. Laid together the combination is what the underfloor heating has to warm through.
The published TOG figures add to 3.68, and even after the UHMA 1 TOG in-situ correction the pair sits at 2.68 TOG, 0.18 TOG over the limit. The carpet is fine; the underlay is doing the damage. Keep Cormar Silken Serenity 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 Silken Serenity and Tredaire Brio: combined TOG for underfloor heating?
Combined in-situ TOG is 2.68, above the 2.5 TOG limit, so Cormar Silken Serenity with Tredaire Brio is not suitable for underfloor heating. Keep the carpet and switch to a low-TOG underlay.