Phase change material (PCM ) can store heat at a constant temperature, which is beneficial to reduce building energy consumption. Herein, we fabricated a PCM board that can store 98-102 J/g heat at 26 °C. The PCM boards were paved as the floor in the real scale office to reduce power for temperature regulation, which led to the reduced energy consumption of 18.8% and 19.7% in winter and summer, respectively. A numerical model is validated by experimental data to evaluate long term performance. The experiment and simulation results both demonstrate the high performance PCM floor for effective reduction in electricity consumption of heating and cooling.