As low-carbon development progresses, integrated energy systems (IES) are increasingly vital for meeting emission reduction goals. A mathematical model for a community IES, based on an energy hub and incorporating energy storage, gas turbine power generation systems, and flexible loads, has been developed. This model thoroughly addresses the features of flexible loads on the user side that may be transferred, shifted, or reduced. Ultimately, an optimal day ahead scheduling model for IES supply and demand is developed to minimize overall operating costs. The economic advantages of independent electricity and thermal scheduling are compared. The simulation analysis of the example demonstrates that flexible scheduling of electrical and thermal loads can greatly lower system operating costs, decrease net load fluctuation between peak and valley, and alleviate peak load demand in the power system.