International Journal of Electrical and Computer Engineering (IJECE) Vol. 12, No. 3, June 2022, pp. 3061~3071 ISSN: 2088-8708, DOI: 10.11591/ijece.v12i3.pp3061-3071  3061 Journal homepage: http://ijece.iaescore.com Functions of fuzzy logic based controllers used in smart building Ali M. Baniyounes 1 , Yazeed Yasin Ghadi 2 , Eyad Radwan 1 , Khalid S. Al-Olimat 3 1 Department of Electrical and Computer Engineering, Applied Science Private University, Amman, Jordan 2 Department of Software Engineering and Computer Science Programs, Al Ain University, Abu Dhabi, United Arab Emirates 3 Department of Electrical and Computer Engineering and Computer Science, Ohio Northern University, Ohio, Unites States America Article Info ABSTRACT Article history: Received Jun 13, 2021 Revised Oct 17, 2021 Accepted Nov 5, 2021 The main aim of this study is to support design and development processes of advanced fuzzy-logic-based controller for smart buildings e.g., heating, ventilation and air conditioning, heating, ventilation and air conditioning (HVAC) and indoor lighting control systems. Moreover, the proposed methodology can be used to assess systems energy and environmental performances, also compare energy usages of fuzzy control systems with the performances of conventional on/off and proportional integral derivative controller (PID). The main objective and purpose of using fuzzy-logic-based model and control is to precisely control indoor thermal comfort e.g., temperature, humidity, air quality, air velocity, thermal comfort, and energy balance. Moreover, this article present and highlight mathematical models of indoor temperature and humidity transfer matrix, uncertainties of users’ comfort preference set-points and a fuzzy algorithm. Keywords: Energy fifth keyword Fuzzy logic Indoor thermal comfort PID controller This is an open access article under the CC BY-SA license. Corresponding Author: Ali M. Baniyounes Department of Electrical and Computer Engineering, Applied Science Private University Al Arab St 21, Amman, Jordan Email: al_younes@asu.edu.jo 1. INTRODUCTION The integration of real-time events with indoor air temperature, humidity, the level of carbon dioxide (CO2) and indoor illuminance level are not a straightforward task using proportional integral derivative (PID) controllers. Thus, a multi-agent control system, are designed and reconfigured in this paper rather than using one multi controllers of each separate control signal. In addition, it is quite difficult to apply and design model free controller to real-time indoor environment control system based on surrounding real life event and real time thus modifying adaptability is included in this study in order to increase controller feasibility. Consequently, suitable mathematical models of controlled goals are essential throughout the design and testing phase, the proposed control strategies. Accordingly, this chapter discusses the mathematical models of the building’s indoor atmosphere including the model of indoor temperature, humidity, the concentration of CO2 level and the indoor illuminance level. The chapter also discusses the mathematical models of lighting and heating, ventilation and air conditioning (HVAC) system and systems’ energy usage and savings. The recent control methods that extensively employed in indoor thermal comfort control mathematical models. The current research, a fuzzy-logic-based controller is designed and modelled in order to control indoor temperature, indoor humidity, indoor air quality and indoor illuminances by integrating real life events such as the usage of ambient air and natural light (day-lighting) into the existing artificial indoor environment while using minimum energy.