A motorized window treatment for controlling the amount of daylight entering a space through a window includes a covering material, a drive shaft, and a motor coupled to the drive shaft for raising and lowering the covering material. The window treatment also includes a spring assist unit for assisting the motor by providing a torque that equals the torque provided by the weight on the cords that lift the covering material at a position midway between fully-open and fully-closed positions to minimize motor usage and conserve battery life. The window treatment may comprise a photosensor for measuring the amount of daylight outside the window and temperature sensors for measuring the temperatures inside and outside of the window. The position of the covering material may be automatically controlled in response to the photosensor and the temperature sensors, or in response to an infrared or radio-frequency remote control.