This paper presents a novel integrated solar collector-storage (ICS) system which incorporates both the collector and the tank in one unit. The system makes use of a transparent insulation, made of narrow horizontal channels filled with a gas of low thermal conductivity e.g., Krypton or Argon, and surrounds the tank. The inner and the outer plate surfaces of the panel is coated using low-e and heat mirror layers respectively. The system is formed of a truncated cone and is provided with a baffle plate that divides the storage water into two parts, an inner part which contains the bulk of the storage water and an outer part, where solar absorption takes place. The baffle acts as insulation in order to prevent heat loss at low insolation and during the night. Two vents were provided at the top and bottom of the baffle to enable circulation of the water between the solar collector section and the bulk of the storage water. Results of numerical analysis have shown that a heat loss coefficient of 0.56 Wm⁻²K⁻¹ for top insulation and 0.63 Wm⁻²K⁻¹ for side insulation could be achieved using a transparent insulation of an overall thickness of 28 mm when coated with a low-e and heat mirror material.