Today, control, automation, and supervisory systems are essential components of HVAC systems for the benefits they offer in managing and optimizing resources. This paper intends to explore the identification of an optimal thermal control strategy that is responsive to the outdoor temperature distribution, and it is respectful of the features of the sub-systems interconnected to the indoor ambient, i.e. the heating system and the building walls. The underlying model returns the dynamic thermal response of a residential home. It exhibits the attractive features of being easy to understand and handle in order to anticipate the future behavior of the system. The main control objective is to reduce energy consumption while ensuring the desired thermal comfort of the occupants. The control action is realized by an open loop which determines the temperature of the hot water supply as a function of the outside temperature. This kind of regulation, as simple as it is, is easily implemented in existing facilities. Simulation results revealed the effectiveness of a suitable control strategy in saving energy without penalizing the occupants’ comfort.