Transfer Function of thermal model

Hi, I'm an amateur, I'm just learning and I have a problem. I want to examine the operation of MPC in Simulink on a ready project from: https://www.mathworks.com/help/simulink/slref/thermal-model-of-a-house.html

I have a problem with determining the transmittance of this system. I understand that transmittance will be a heater and a house in a row? As far as I know, I have to save this transmittance in the matlab's command window and then import it to the MPC Toolbox. I think well?