This paper presents the smart control for variable speed pumps in building heating and cooling systems to enhance their energy efficiencies. The smart control method is a context aware algorithm for a variable speed pump without sensors. The context aware algorithm recognizes the circumstances through an inverter controller mounted to the pump without any differential pressure sensor. The smart control diagnose a whole system using the algorithm and adjust a variable speed pump to the system load. This paper described a control technology for verifying the algorithm under various environments. This smart control method of variable speed pumping system improve the efficiency of system such as building cooling and heating.