TogCheck
Combined TOG result

Cormar Primo Tweeds and Tredaire King (Duralay King): combined TOG for underfloor heating

The combined TOG for Cormar Primo Tweeds over Tredaire King (Duralay King), worked against the UHMA underfloor heating rule.

1.52.5
1TOG in situ
Pass · limit 2.5
Published TOG stack (carpet + underlay)
carpet 1.2
underlay 0.8
limit

Combined against the UHMA 2.5 TOG underfloor-heating limit. Under 1.5 also suits a low-temperature heat pump.

Carpet TOGUnderlay TOGPassMarginalFail
Combined in-situ TOG is 1, under the 2.5 TOG limit, so Cormar Primo Tweeds with Tredaire King (Duralay King) is suitable for a standard underfloor heating system. It is also under 1.5 TOG, so it suits a low-temperature heat pump run.
The combined-TOG calculation
CarpetCormar Primo Tweeds (1.2 TOG)
UnderlayTredaire King (Duralay King) (0.8 TOG)
Published sum2 TOG
UHMA in-situ correctionminus 1 TOG
Combined in-situ TOG1 TOG
Standard UFH limit2.5 TOG
Heat pump targetunder 1.5 TOG

Cormar Primo Tweeds is rated 1.2 TOG and Tredaire King (Duralay King) is rated 0.8 TOG. Laid together the combination is what the underfloor heating has to warm through.

The published TOG figures add to 2. The UHMA rule subtracts 1 TOG because tests showed real in-situ resistance runs about a TOG below the paper sum, giving 1 TOG. That clears both the standard limit and the tighter heat-pump target.

Related checks
Cormar Primo Tweeds TOG value1.2 TOGTredaire King (Duralay King) TOG rating0.8 TOGCormar Pimlico with Tredaire King (Duralay King)0.8 TOG, passCormar Primo Textures Ribbed with Tredaire King (Duralay King)0.8 TOG, passCormar Primo Textures Weave with Tredaire King (Duralay King)0.7 TOG, passCormar Apollo Plus with Tredaire King (Duralay King)0.9 TOG, pass

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 Tredaire King underlay datasheet