diff --git a/exports/energy_systems/heat_pump_export.py b/exports/energy_systems/heat_pump_export.py
index 2b755d38..e5828608 100644
--- a/exports/energy_systems/heat_pump_export.py
+++ b/exports/energy_systems/heat_pump_export.py
@@ -157,6 +157,10 @@ class HeatPumpExport:
       constants_dict = yaml.load(file, Loader=yaml.FullLoader)
       for key, value in constants_dict.items():
         self._input_data[key] = value
+    # compute water to water HP specific values
+    if self._water_temp is not None:
+      self._input_data["HPDisactivationTemperature"] = self._input_data["HPSupTemp"] - 5
+      self._input_data["HPReactivationTemperature"] = self._input_data["HPSupTemp"] - 18
 
     # compute maximum demand. TODO: This should come from catalog in the future
     max_demand = self._compute_max_demand()
diff --git a/unittests/test_energy_systems_water_to_water_hp.py b/unittests/test_energy_systems_water_to_water_hp.py
index 9917a629..9517476b 100644
--- a/unittests/test_energy_systems_water_to_water_hp.py
+++ b/unittests/test_energy_systems_water_to_water_hp.py
@@ -47,10 +47,7 @@ class TestEnergySystemsFactory(TestCase):
       'FuelPrice': 0.12,
       'FuelEF': 1887,
       'FuelDensity': 0.717,
-      'HPSupTemp': 60,
-      # parameters below depend on HPSupTem
-      'HPDisactivationTemperature': 55,
-      'HPReactivationTemperature': 42
+      'HPSupTemp': 60
     }
 
     EnergySystemsExportFactory(self._city, user_input, 'ClimateMaster 156 kW', self._output_path).export('water')