diff --git a/IBPSA/Resources/ReferenceResults/Dymola/IBPSA_ThermalZones_ReducedOrder_Examples_SimpleRoomTwoElementsNonConstantTGround.txt b/IBPSA/Resources/ReferenceResults/Dymola/IBPSA_ThermalZones_ReducedOrder_Examples_SimpleRoomTwoElementsNonConstantTGround.txt
new file mode 100644
index 0000000000..00558d83d5
--- /dev/null
+++ b/IBPSA/Resources/ReferenceResults/Dymola/IBPSA_ThermalZones_ReducedOrder_Examples_SimpleRoomTwoElementsNonConstantTGround.txt
@@ -0,0 +1,14 @@
+last-generated=2023-09-14
+statistics-initialization=
+{
+  "linear": "5"
+}
+statistics-simulation=
+{
+  "linear": "0, 3, 0",
+  "nonlinear": " ",
+  "number of continuous time states": "4",
+  "numerical Jacobians": "0"
+}
+time=[0e+00, 3.1536e+07]
+eqAirTemp.TEqAir=[2.789571533203125e+02, 2.813718017578125e+02, 2.7872587890625e+02, 2.807901184082031e+02, 2.835259521484375e+02, 2.823024597167969e+02, 2.827985473632813e+02, 2.822135131835938e+02, 2.784553283691406e+02, 2.797283508300781e+02, 2.843675231933594e+02, 2.796825317382812e+02, 2.830658447265625e+02, 2.863615112304688e+02, 2.829901916503906e+02, 2.81193115234375e+02, 2.834943542480469e+02, 2.822643676757813e+02, 2.849333984375e+02, 2.8688466796875e+02, 2.813687744140625e+02, 2.854065185546875e+02, 2.824746765136719e+02, 2.820121215820312e+02, 2.881613098144531e+02, 2.850013122558594e+02, 2.823730773925781e+02, 2.873432434082031e+02, 2.857710876464844e+02, 2.85406591796875e+02, 2.900100402832031e+02, 2.826182189941406e+02, 2.84790185546875e+02, 2.966639404296875e+02, 2.837040283203125e+02, 2.864047241210938e+02, 2.959377624511719e+02, 2.883143005371094e+02, 2.897021667480469e+02, 2.957674682617188e+02, 2.864564819335938e+02, 2.896947265625e+02, 2.955205017089844e+02, 2.871305236816406e+02, 2.91426025390625e+02, 2.9104345703125e+02, 2.86251953125e+02, 2.90456201171875e+02, 2.876586730957031e+02, 2.879760803222656e+02, 2.924863586425781e+02, 2.866445068359375e+02, 2.888368591308594e+02, 2.952922973632812e+02, 2.882718566894531e+02, 2.897318420410156e+02, 2.960734008789062e+02, 2.874204406738281e+02, 2.916609802246094e+02, 2.970692016601562e+02, 2.87395751953125e+02, 2.934731872558594e+02, 2.889349975585938e+02, 2.884504028320313e+02, 2.923549438476563e+02, 2.880719299316406e+02, 2.882120971679688e+02, 2.9177724609375e+02, 2.858329772949219e+02, 2.879469116210938e+02, 2.915469055175781e+02, 2.855946655273438e+02, 2.865959594726563e+02, 2.939826416015625e+02, 2.875797424316406e+02, 2.867238159179688e+02, 2.938005920410156e+02, 2.847250549316406e+02, 2.881406921386719e+02, 2.924451721191406e+02, 2.846399841308594e+02, 2.869987976074219e+02, 2.848623596191406e+02, 2.824324584960938e+02, 2.857318481445312e+02, 2.833520812988281e+02, 2.841896728515625e+02, 2.867588134765625e+02, 2.826075927734375e+02, 2.824429504394531e+02, 2.851797180175781e+02, 2.797426086425781e+02, 2.819598083496094e+02, 2.841822814941406e+02, 2.791549987792969e+02, 2.806098937988281e+02, 2.82980029296875e+02, 2.807776794433594e+02, 2.813313049316406e+02, 2.808358093261719e+02, 2.823453063964844e+02]
diff --git a/IBPSA/Resources/Scripts/Dymola/ThermalZones/ReducedOrder/Examples/SimpleRoomTwoElementsNonConstantTGround.mos b/IBPSA/Resources/Scripts/Dymola/ThermalZones/ReducedOrder/Examples/SimpleRoomTwoElementsNonConstantTGround.mos
new file mode 100644
index 0000000000..d9cef8cf7f
--- /dev/null
+++ b/IBPSA/Resources/Scripts/Dymola/ThermalZones/ReducedOrder/Examples/SimpleRoomTwoElementsNonConstantTGround.mos
@@ -0,0 +1,12 @@
+simulateModel("IBPSA.ThermalZones.ReducedOrder.Examples.SimpleRoomTwoElementsNonConstantTGround", tolerance=1e-6, stopTime=3.1536e+007, numberOfIntervals=0, outputInterval=3600, method="CVode", resultFile="SimpleRoomTwoElementsNonConstantTGround");
+createPlot(id = 1,
+ position = {55, 50, 697, 502},
+ x = "time",
+ y = {"eqAirTemp.TEqAir"},
+ autoscale = true,
+ autoerase = true,
+ autoreplot = true,
+ grid = true,
+ color = true,
+ leftTitleType = 1,
+ bottomTitleType = 1);
diff --git a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/PartialVDI6007.mo b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/PartialVDI6007.mo
index f83dc4253f..c49578f4ee 100644
--- a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/PartialVDI6007.mo
+++ b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/PartialVDI6007.mo
@@ -10,7 +10,8 @@ partial model PartialVDI6007
   parameter Real wfGro(unit="1")
     "Weight factor of the ground (0 if not considered)";
   parameter Modelica.Units.SI.Temperature TGro
-    "Temperature of the ground in contact with floor plate";
+    "Constant temperature of the ground in contact with floor plate"
+    annotation(Dialog(enable=not TGroundFromInput));
   parameter Modelica.Units.SI.CoefficientOfHeatTransfer hConWallOut
     "Exterior walls convective coefficient of heat transfer (outdoor)";
   parameter Modelica.Units.SI.CoefficientOfHeatTransfer hRad
@@ -18,6 +19,9 @@ partial model PartialVDI6007
   parameter Boolean withLongwave=true
     "Set to true to include longwave radiation exchange"
     annotation(choices(checkBox = true));
+  parameter Boolean TGroundFromInput=false
+    "Set to true to use TGro_in input connector instead of TGro constant"
+    annotation(choices(checkBox = true));
 
   Modelica.Units.SI.Temperature TEqWall[n] "Equivalent wall temperature";
   Modelica.Units.SI.Temperature TEqWin[n] "Equivalent window temperature";
@@ -61,6 +65,24 @@ partial model PartialVDI6007
     extent={{-20,-20},{20,20}},
     rotation=-90,
     origin={0,120})));
+  Modelica.Blocks.Interfaces.RealInput TGro_in(
+    final quantity="ThermodynamicTemperature",
+    final unit="K",
+    displayUnit="degC") if TGroundFromInput
+    "Temperature of the ground in contact with floor plate"
+    annotation (Placement(
+        transformation(
+        extent={{-20,-20},{20,20}},
+        rotation=90,
+        origin={0,-120})));
+
+protected
+  SourceSelector TGroSouSel(final useInput=TGroundFromInput, p=TGro)
+    "Input selector for ground temperature" annotation (Placement(
+        transformation(
+        extent={{-10,-10},{10,10}},
+        rotation=90,
+        origin={8,-40})));
 
 initial equation
   assert(noEvent(abs(sum(wfWall) + sum(wfWin) + wfGro) > 0.1),
@@ -80,6 +102,8 @@ equation
     TEqWall=TDryBul.+delTEqSW;
   end if;
 
+  connect(TGro_in, TGroSouSel.uCon)
+    annotation (Line(points={{0,-120},{0,-51}}, color={0,0,127}));
   annotation (  Icon(coordinateSystem(preserveAspectRatio=false,
   extent={{-100,-100},{100,100}}),
   graphics={
@@ -120,6 +144,12 @@ equation
   revisions="<html>
   <ul>
   <li>
+  May 5, 2023, by Philip Groesdonk:<br/>
+  Added an option for non-constant ground temperature from an input connector.
+  This is for
+  <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/1744\">#1744</a>.
+  </li>
+  <li>
   July 11, 2019, by Katharina Brinkmann:<br/>
   Renamed <code>alphaRad</code> to <code>hRad</code>,
   <code>alphaWinOut</code> to <code>hConWallOut</code>
diff --git a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/SourceSelector.mo b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/SourceSelector.mo
new file mode 100644
index 0000000000..4bc00b72fa
--- /dev/null
+++ b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/SourceSelector.mo
@@ -0,0 +1,51 @@
+within IBPSA.ThermalZones.ReducedOrder.EquivalentAirTemperature.BaseClasses;
+block SourceSelector
+  "Block that selects as its output either a parameter value or its input"
+  extends Modelica.Blocks.Interfaces.SO;
+  parameter Boolean useInput "Use input (if true) or parameter value (if false)"
+    annotation(Evaluate=true);
+  parameter Real p "Parameter value";
+  Modelica.Blocks.Interfaces.RealInput uCon if useInput
+    "Input signal from input connector"
+    annotation (Placement(transformation(extent={{-140,40},{-100,80}}),
+        iconTransformation(extent={{-120,70},{-100,90}})));
+equation
+  if not useInput then
+    y = p;
+  end if;
+  connect(uCon, y);
+  annotation (
+  defaultComponentName="souSel",
+Documentation(info="<html>
+<p>
+Block that produces at its output the input value <code>uCon</code>
+or the parameter value <code>p</code> depending on the parameter value
+<code>useInput</code>.
+</p>
+</html>", revisions="<html>
+<ul>
+<li>
+June 28, 2023, by Philip Groesdonk:<br/>
+First implementation.
+</li>
+</ul>
+</html>"),
+    Icon(graphics={
+      Rectangle(
+          extent={{-100,100},{100,-100}},
+          fillColor={210,210,210},
+          fillPattern=FillPattern.Solid,
+          borderPattern=BorderPattern.Raised),
+        Line(points={{12,0},{100,0}},
+          color={0,0,127}),
+        Line(points={{-100,80},{-38,80}},
+          color={0,0,127}),
+        Line(points={{-40,80},{8,0}},
+          color={0,0,127},
+          visible=useInput,
+          thickness=1),
+        Ellipse(lineColor={0,0,255},
+          pattern=LinePattern.None,
+          fillPattern=FillPattern.Solid,
+          extent={{2,-8},{18,8}})}));
+end SourceSelector;
diff --git a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/package.order b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/package.order
index 609fb4d171..52fe857587 100644
--- a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/package.order
+++ b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/BaseClasses/package.order
@@ -1 +1,2 @@
 PartialVDI6007
+SourceSelector
diff --git a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007.mo b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007.mo
index 8608ffa605..370394150d 100644
--- a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007.mo
+++ b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007.mo
@@ -9,10 +9,16 @@ initial equation
 
 equation
   delTEqLWWin=delTEqLW;
-  TEqAir = TEqWall*wfWall + TEqWin*wfWin + TGro*wfGro;
+  TEqAir = TEqWall*wfWall + TEqWin*wfWin +  TGroSouSel.y*wfGro;
   annotation (defaultComponentName = "equAirTem",Documentation(revisions="<html>
   <ul>
   <li>
+  May 5, 2023, by Philip Groesdonk:<br/>
+  Added an option for non-constant ground temperature from an input connector.
+  This is for
+  <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/1744\">#1744</a>.
+  </li>
+  <li>
   September 26, 2016, by Moritz Lauster:<br/>
   Moved calculations to <a href=\"modelica://IBPSA.ThermalZones.ReducedOrder.EquivalentAirTemperature.BaseClasses.PartialVDI6007\">
   IBPSA.ThermalZones.ReducedOrder.EquivalentAirTemperature.BaseClasses.PartialVDI6007</a>.
diff --git a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007WithWindow.mo b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007WithWindow.mo
index 0375605f4e..0797b2d722 100644
--- a/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007WithWindow.mo
+++ b/IBPSA/ThermalZones/ReducedOrder/EquivalentAirTemperature/VDI6007WithWindow.mo
@@ -21,11 +21,17 @@ initial equation
 
 equation
   delTEqLWWin=(TBlaSky - TDryBul)*hRad/(hRad + hConWinOut);
-  TEqAir = TEqWall*wfWall + TGro*wfGro;
+  TEqAir = TEqWall*wfWall +  TGroSouSel.y*wfGro;
   TEqAirWin = TEqWin*wfWin;
   annotation (defaultComponentName = "equAirTem",Documentation(revisions="<html>
   <ul>
   <li>
+  May 5, 2023, by Philip Groesdonk:<br/>
+  Added an option for non-constant ground temperature from an input connector.
+  This is for
+  <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/1744\">#1744</a>.
+  </li>
+  <li>
   July 11, 2019, by Katharina Brinkmann:<br/>
   Renamed <code>alphaWinOut</code> to <code>hConWinOut</code>
   </li>
diff --git a/IBPSA/ThermalZones/ReducedOrder/Examples/SimpleRoomTwoElementsNonConstantTGround.mo b/IBPSA/ThermalZones/ReducedOrder/Examples/SimpleRoomTwoElementsNonConstantTGround.mo
new file mode 100644
index 0000000000..9375751936
--- /dev/null
+++ b/IBPSA/ThermalZones/ReducedOrder/Examples/SimpleRoomTwoElementsNonConstantTGround.mo
@@ -0,0 +1,60 @@
+within IBPSA.ThermalZones.ReducedOrder.Examples;
+model SimpleRoomTwoElementsNonConstantTGround
+  "Illustrates the use of non-constant ground temperature for equivalent air temperature calculation"
+  extends Modelica.Icons.Example;
+  extends IBPSA.ThermalZones.ReducedOrder.Examples.SimpleRoomTwoElements(eqAirTemp(
+      wfWall={0.15,0.35},
+      wfGro=0.5,
+        TGroundFromInput=true));
+
+
+
+  Modelica.Blocks.Sources.Trapezoid TGroTrapezoidSource(
+    amplitude=10,
+    rising=7884000,
+    width=7884000,
+    falling=7884000,
+    period=31536000,
+    offset=280.15,
+    startTime=5184000) "Trapezoid-shaped source for ground temperature"
+    annotation (Placement(transformation(extent={{-42,-52},{-22,-32}})));
+equation
+
+  connect(TGroTrapezoidSource.y, eqAirTemp.TGro_in)
+    annotation (Line(points={{-21,-42},{-14,-42},{-14,-16}}, color={0,0,127}));
+  annotation ( Documentation(info="<html>
+<p>
+This example shows the application of
+<a href=\"IBPSA.ThermalZones.ReducedOrder.RC.TwoElements\">
+IBPSA.ThermalZones.ReducedOrder.RC.TwoElements</a>
+in connection with equivalent air temperature calculation in
+<a href=\"IBPSA.ThermalZones.ReducedOrder.EquivalentAirTemperature.VDI6007WithWindow\">
+IBPSA.ThermalZones.ReducedOrder.EquivalentAirTemperature.VDI6007WithWindow</a>,
+where the ground temperature is not a constant, but has a trapezoid source.
+Apart from that, it is identical to <a href=\"IBPSA.ThermalZones.ReducedOrder.Examples.SimpleRoomTwoElements\">
+IBPSA.ThermalZones.ReducedOrder.Examples.SimpleRoomTwoElements</a>.
+<h4>References</h4>
+<p>VDI. German Association of Engineers Guideline VDI 6007-1
+March 2012. Calculation of transient thermal response of rooms
+and buildings - modelling of rooms.</p>
+</html>",   revisions="<html>
+<ul>
+<li>
+June 29, 2023, by Philip Groesdonk:<br/>
+First implementation.<br/>
+This is for
+<a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/1744\">IBPSA, #1744</a>.
+</li>
+</ul>
+</html>"),
+  experiment(
+      StopTime=31536000,
+      Interval=3600,
+      Tolerance=1e-06,
+      __Dymola_Algorithm="Dassl"),
+  __Dymola_Commands(file=
+  "modelica://IBPSA/Resources/Scripts/Dymola/ThermalZones/ReducedOrder/Examples/SimpleRoomTwoElementsNonConstantTGround.mos"
+        "Simulate and plot"),
+    Diagram(coordinateSystem(extent={{-100,-120},{100,100}})),
+    Icon(coordinateSystem(extent={{-100,-100},{100,100}})));
+end SimpleRoomTwoElementsNonConstantTGround;
diff --git a/IBPSA/ThermalZones/ReducedOrder/Examples/package.order b/IBPSA/ThermalZones/ReducedOrder/Examples/package.order
index d0f4429ce2..36115c644e 100644
--- a/IBPSA/ThermalZones/ReducedOrder/Examples/package.order
+++ b/IBPSA/ThermalZones/ReducedOrder/Examples/package.order
@@ -3,3 +3,4 @@ SimpleRoomFourElementsTraceSubstance
 SimpleRoomOneElement
 SimpleRoomThreeElements
 SimpleRoomTwoElements
+SimpleRoomTwoElementsNonConstantTGround