This article presents an integrated thermal and dynamic model of Electric Vehicles (EV) to assess the effect of implementing a passive heating method on increasing the electric range of a typical light-duty electric vehicle in cold climates. By introducing passive thermal storage using phase change materials (PCM) temperature of the vehicle's compartment is maintained at certain set point for comfort. Thermal model uses the overall heat transfer coefficient from the compartment to the ambient in cold weather and assumes uniform temperature distribution in the compartment. We use real-world driving, parking and estimated probability of charging for more than 10 thousand daily duty cycles recorded in the city of Winnipeg, Manitoba, Canada. We simulate driving a typical light-duty electric vehicle (EV), with 24 kWh of battery storage over 44 million data points of the database in low temperatures ranging from 0°C to -20°C. While the EV is plugged in, PCM-based heat storage absorbs heat generated by an electric heater, also connected to the electric grid, to change phase. Based on the results of the simulation, inclusion of PCM in the seat cushions can help to maintain the temperature of vehicle's compartment constant at 15°C for an increase of the electric range up to 21%.