Concerns over the impact of the environment on the massive usage of fossil fuels, combined with soaring energy prices, triggered increased interest in the use of solar energy. Solar energy is abundant, provides an important saving to the consumer, and contributes to a personal comfort without environmental damage. One of the most attractive applications of solar energy is for hot water usage in ... [Show full abstract] the public and commercial sector. The available building surface for the residential, commercial and industrial sector is approximately 110,000,000 m 2 . Hence, the potential for solar heaters for Malaysia is 75 GW(thermal). There are over 100 hospitals and hotels throughout the nation that the existing hot water system can be converted to solar assisted system and hence increase the market of the solar energy systems. Hospitals and hotels utilized over 30 % of the total energy consumption for water heating. A case study of such facilities is the Hospital Universiti Kebangsaan Malaysia (HUKM)) was presented. Presently, cold water enters the calorifiers directly, which are heated by LPG boilers. Boiling time is relatively long, hence larger amount of LPG is used and much amount of greenhouse gases is released. The hot water system for the hospital is provided by a boiler with a capacity of 2.1 million kcal/hr. The fuel used is LPG. A total of eight calorifiers are used. Each calorifier has a capacity of 13,500 litre/hr. The unit is running 24 hours a day. The average solar radiation for Kuala Lumpur is 16.92 MJ / m² / day. The evacuated tube collectors with all the required controls system have been proposed. Simple calculations on the energy output, savings on LPG and reduction of CO2 have been conducted. Prelimanary results indicated that the saving on LPG based on proposed system was more than 20%. With a prospect of 100 hospitals and hotels throughout the nation, this project shall improve public awareness in energy conservation in the hot water production of their buildings and increase the market of the solar energy systems.