The paper deals with falling film heat transfer across horizontal copper tubes at different tube surface geometries, mass flow rates, heat fluxes and weight percentage of salt in water salt solution at atmospheric pressure. The falling film heat transfer coefficient is significantly affected by heat flux, film Reynolds number and water salt solution for three types of augmented tubes viz. spiral, splined and smooth. This paper considers the influence of operating parameters on heat transfer coefficient using Fuzzy-Topsis applications. The experimental results reveal that falling film heat transfer has been greatly enhanced in case of spiral tube when compared with splined and smooth tubes. The spiral tube shows significant heat transfer performance than other two tubes for a given heat flux and Reynolds number as heat flux increases surface temperature also increases and increment in surface temperature of smooth tube is greater than spiral and spline tube for given heat flux and Reynolds number. As mass flow rate increases, surface temperature of all three tubes decreases but for a given heat flux and Reynolds number smooth tube has more surface temperature than other two tubes.