This book describes different control strategies adapted to heat pumps, at the purpose of increasing energy flexibility in buildings. It reports on the development of both simple rule-based controls (RBC) and advanced model predictive controls (MPC). These are tested and compared in both simulation and experimental setups. The book analyzes in detail all the different steps, including the development and tuning of the controllers, their testing in experimental settings and simulation studies.  Bridging between advanced control systems theory concepts and practical needs, and discussing the advantages and main challenges of MPC and RBC controllers in terms of efficiency of heat pump operation, electricity prices, emission values, and users'' comfort, this book offers an in-depth evaluation of innovative control strategies applied to energy demand management in buildings.