diff --git a/four_levels_model.py b/four_levels_model.py
index 54b7d50..d820079 100644
--- a/four_levels_model.py
+++ b/four_levels_model.py
@@ -391,4 +391,4 @@ class HeatingGas:
         self.total_gas_heating = total_injected_power * (self.fc_pah/self.n_c) * 2.7e-4
         #2.7e-4 : elemental abundance of C relative to H (Tielens 2021)  
                 
-        return self.total_gas_heating, self.g_0 , self.gamma, self.t_gas, self.n_e, self.n_c
\ No newline at end of file
+        return self.total_gas_heating, self.heating_efficiency, self.g_0 , self.gamma, self.t_gas, self.n_e, self.n_c
\ No newline at end of file
--
libgit2 0.21.2