diff --git a/src/fix_heat.cpp b/src/fix_heat.cpp
index dfe1a356a1..c9b361a9f8 100644
--- a/src/fix_heat.cpp
+++ b/src/fix_heat.cpp
@@ -34,6 +34,11 @@ FixHeat::FixHeat(LAMMPS *lmp, int narg, char **arg) : Fix(lmp, narg, arg)
 {
   if (narg < 4) error->all("Illegal fix heat command");
 
+  scalar_flag = 1;
+  scalar_vector_freq = 1;
+  extscalar = 0;
+  r = 1.0;
+
   nevery = atoi(arg[3]);
   if (nevery <= 0) error->all("Illegal fix heat command");