diff --git a/doc/src/fix_add_heat.rst b/doc/src/fix_add_heat.rst
new file mode 100644
index 0000000000..3964c96b27
--- /dev/null
+++ b/doc/src/fix_add_heat.rst
@@ -0,0 +1,87 @@
+.. index:: fix add/heat
+
+fix add/heat command
+====================
+
+Syntax
+""""""
+
+.. code-block:: LAMMPS
+
+   fix ID group-ID add/heat rate values ...
+
+* ID, group-ID are documented in :doc:`fix <fix>` command
+* add/heat = style name of this fix command
+* rate = rate of heat flow (energy/time units)
+* zero or more keyword/value pairs may be appended to args
+* keyword = *overwrite*
+
+  .. parsed-literal::
+
+       *overwrite* = sets the heat flow instead of adding it
+
+Examples
+""""""""
+
+.. code-block:: LAMMPS
+
+   fix 1 all add/heat v_heat
+   fix 1 all add/heat 1.0 overwrite
+
+Description
+"""""""""""
+
+This fix adds heat to particles every timestep at a given rate. The rate
+can be can be specified as an equal-style or atom-style
+:doc:`variable <variable>`.  If the value is a variable, it should be
+specified as v_name, where name is the variable name.  In this case, the
+variable will be evaluated each time step, and its value will be used to
+determine the rate of heat added.
+
+Equal-style variables can specify formulas with various mathematical
+functions and include :doc:`thermo_style <thermo_style>` command
+keywords for the simulation box parameters, time step, and elapsed time.
+Thus, it is easy to specify time-dependent heating.
+
+Atom-style variables can specify the same formulas as equal-style
+variables but can also include per-atom values, such as atom
+coordinates.  Thus, it is easy to specify a spatially-dependent heating
+field with optional time-dependence as well.
+
+If the *overwrite* keyword is specified, this fix will effectively set
+the total heat flow on a particle, overwriting contributions from other
+pair styles.
+
+----------
+
+Restart, fix_modify, output, run start/stop, minimize info
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+No information about this fix is written to :doc:`binary restart files <restart>`.
+None of the :doc:`fix_modify <fix_modify>` options are relevant to this fix.
+No global or per-atom quantities are stored by this fix for access by various
+:doc:`output commands <Howto_output>`. No parameter of this fix can be used
+with the *start/stop* keywords of the :doc:`run <run>` command.  This fix is
+not invoked during :doc:`energy minimization <minimize>`.
+
+Restrictions
+""""""""""""
+
+This pair style is part of the GRANULAR package.  It is
+only enabled if LAMMPS was built with that package.
+See the :doc:`Build package <Build_package>` page for more info.
+
+This fix requires that atoms store temperature and heat flow
+as defined by the :doc:`fix property/atom <fix_property_atom>` command.
+
+Related commands
+""""""""""""""""
+
+:doc:`fix heat/flow <fix_heat_flow>`,
+:doc:`fix property/atom <fix_property_atom>`,
+:doc:`fix rheo/thermal <fix_rheo_thermal>`
+
+Default
+"""""""
+
+none
diff --git a/doc/src/fix_heat_flow.rst b/doc/src/fix_heat_flow.rst
index 1ca99a1686..aa2b3fbc06 100644
--- a/doc/src/fix_heat_flow.rst
+++ b/doc/src/fix_heat_flow.rst
@@ -1,7 +1,7 @@
 .. index:: fix heat/flow
 
 fix heat/flow command
-==========================
+=====================
 
 Syntax
 """"""
@@ -56,13 +56,19 @@ not invoked during :doc:`energy minimization <minimize>`.
 Restrictions
 """"""""""""
 
+This pair style is part of the GRANULAR package.  It is
+only enabled if LAMMPS was built with that package.
+See the :doc:`Build package <Build_package>` page for more info.
+
 This fix requires that atoms store temperature and heat flow
 as defined by the :doc:`fix property/atom <fix_property_atom>` command.
 
 Related commands
 """"""""""""""""
 
-:doc:`pair granular <pair_granular>`, :doc:`fix property/atom <fix_property_atom>`
+:doc:`pair granular <pair_granular>`,
+:doc:`fix add/heat <fix_add_heat>`,
+:doc:`fix property/atom <fix_property_atom>`
 
 Default
 """""""
diff --git a/doc/src/fix_rheo_thermal.rst b/doc/src/fix_rheo_thermal.rst
index 63d9f817ad..2ffb665bb7 100644
--- a/doc/src/fix_rheo_thermal.rst
+++ b/doc/src/fix_rheo_thermal.rst
@@ -109,7 +109,8 @@ Related commands
 
 :doc:`fix rheo <fix_rheo>`,
 :doc:`pair rheo <pair_rheo>`,
-:doc:`compute rheo/property/atom <compute_rheo_property_atom>`
+:doc:`compute rheo/property/atom <compute_rheo_property_atom>`,
+:doc:`fix add/heat <fix_add_heat>`
 
 Default
 """""""