diff --git a/doc/compute_heat_flux.html b/doc/compute_heat_flux.html
index 7d9915c100..d930637f3c 100644
--- a/doc/compute_heat_flux.html
+++ b/doc/compute_heat_flux.html
@@ -161,8 +161,11 @@ thermo	     $d
 fix       NVT all nvt temp $T $T 10 drag 0.2
 run       8000 
 </PRE>
-<P># -------------- flux calculation ---------------
+<P># -------------- flux calculation, switch to NVE if desired --------
 </P>
+<PRE>#unfix     NVT
+#fix       NVE all nve 
+</PRE>
 <PRE>reset_timestep  0
 compute   myKE all ke/atom
 compute   myPE all pe/atom
diff --git a/doc/compute_heat_flux.txt b/doc/compute_heat_flux.txt
index f843da6f65..3826b24a42 100644
--- a/doc/compute_heat_flux.txt
+++ b/doc/compute_heat_flux.txt
@@ -158,7 +158,10 @@ velocity  all create $T 102486 mom yes rot yes dist gaussian
 fix       NVT all nvt temp $T $T 10 drag 0.2
 run       8000 :pre
 
-# -------------- flux calculation ---------------
+# -------------- flux calculation, switch to NVE if desired --------
+
+#unfix     NVT
+#fix       NVE all nve :pre
 
 reset_timestep  0
 compute   myKE all ke/atom