TogCheck
Combined TOG result

Cormar Primo Naturals and Duralay Technics 5: combined TOG for underfloor heating

The combined TOG for Cormar Primo Naturals over Duralay Technics 5, worked against the UHMA underfloor heating rule.

1.52.5
0.96TOG in situ
Pass · limit 2.5
Published TOG stack (carpet + underlay)
carpet 1.4
underlay 0.56
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 0.96, under the 2.5 TOG limit, so Cormar Primo Naturals with Duralay Technics 5 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 Naturals (1.4 TOG)
UnderlayDuralay Technics 5 (0.56 TOG)
Published sum1.96 TOG
UHMA in-situ correctionminus 1 TOG
Combined in-situ TOG0.96 TOG
Standard UFH limit2.5 TOG
Heat pump targetunder 1.5 TOG

Cormar Primo Naturals is rated 1.4 TOG and Duralay Technics 5 is rated 0.56 TOG. Laid together the combination is what the underfloor heating has to warm through.

The published TOG figures add to 1.96. The UHMA rule subtracts 1 TOG because tests showed real in-situ resistance runs about a TOG below the paper sum, giving 0.96 TOG. That clears both the standard limit and the tighter heat-pump target.

Related checks
Cormar Primo Naturals TOG value1.4 TOGDuralay Technics 5 TOG rating0.56 TOGCormar Pimlico with Duralay Technics 50.56 TOG, passCormar Primo Textures Ribbed with Duralay Technics 50.56 TOG, passCormar Primo Textures Weave with Duralay Technics 50.46 TOG, passCormar Apollo Plus with Duralay Technics 50.66 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 Technics 5 underlay datasheet