diff --git a/src/thermophysicalModels/basic/heThermo/heThermo.C b/src/thermophysicalModels/basic/heThermo/heThermo.C
index 466640e15..0cc1354ff 100644
--- a/src/thermophysicalModels/basic/heThermo/heThermo.C
+++ b/src/thermophysicalModels/basic/heThermo/heThermo.C
@@ -736,7 +736,7 @@ Foam::heThermo<BasicThermo, MixtureType>::kappaEff
     const volScalarField& alphat
 ) const
 {
-    tmp<Foam::volScalarField> kappaEff(Cp()*alphaEff(alphat));
+    tmp<Foam::volScalarField> kappaEff(Cp()*(this->alpha_ + alphat));
     kappaEff().rename("kappaEff");
     return kappaEff;
 }
@@ -756,7 +756,11 @@ Foam::heThermo<BasicThermo, MixtureType>::kappaEff
             this->p_.boundaryField()[patchi],
             this->T_.boundaryField()[patchi],
             patchi
-        )*alphaEff(alphat, patchi);
+        )
+       *(
+           this->alpha_.boundaryField()[patchi]
+         + alphat
+        );
 }