diff --git a/src/geophires_x/SurfacePlantHeatPump.py b/src/geophires_x/SurfacePlantHeatPump.py
index 09316b65..34f72e1c 100644
--- a/src/geophires_x/SurfacePlantHeatPump.py
+++ b/src/geophires_x/SurfacePlantHeatPump.py
@@ -41,7 +41,7 @@ def __init__(self, model: Model):
 
         self.heat_pump_cop = self.ParameterDict[self.heat_pump_cop.Name] = floatParameter(
             "Heat Pump COP",
-            value=5,
+            DefaultValue=5,
             Min=1,
             Max=10,
             UnitType=Units.PERCENT,