diff --git a/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C b/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C
index 6fa334158a..36ff9f4cad 100644
--- a/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C
+++ b/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C
@@ -324,6 +324,8 @@ void reactingOneDim::solveEnergy()
     (
         fvm::ddt(rho_, h_)
       - fvm::laplacian(alpha, h_)
+      + fvc::laplacian(alpha, h_)
+      - fvc::laplacian(kappa(), T())
      ==
         chemistrySh_
       - fvm::Sp(solidChemistry_->RRg(), h_)