Today, solar energy is considered to supply human thermal energy needs. One of these uses is getting help from solar energy to supply heating energy required for the building and the purpose of the facade collectors is providing this energy. In this study, the performance of two solar facade collectors has been investigated. The first study is performed on a flat plate solar collector model, which assumed natural and forced convection heat transfer. The working fluid of the solar collector model has been changed in each study. The fluids that considered in this study are water, water-ethylene glycol, water-nanoparticles and water-ethylene glycol nanoparticles. The results show that water-ethylene glycol mixture has the lowest heat transfer coefficient among the tested fluids. Natural and forced convection heat transfer coefficients of water-ethylene glycol mixture on average 20. 3 and 15.5 percent decreased with respect to water based fluid. Also addition of nanoparticles improved the heat transfer coefficient of the base fluid, as in the natural and forced convection 6.3 and 2.5 percent improvement is obtained in heat transfer coefficient respectively for nanofluids with 0.6 and 0.4 wt% silicon dioxide water based fluid. For nanofluid with water-ethylene glycol based fluid maximum improvement in heat transfer coefficient is 3.8% for 0.6% by weight silicon oxide. In continue of work the new form of solar facade collector was built and its performance was studied in different conditions. The facade collectors due to their influence on the external of buildings, their exterior architecture should be compatible with that. To fulfil this, absorber surface colour coating has been changed and the results show that the efficiency of the collector is related to the absorber colour coating. Among the colour coatings tested, black absorber had the highest thermal efficiency and blue coating had the lowest, in average efficiency of blue paint was 19.51 percent lower than the collector with black paint. Also the absorber plate tube pattern has been changed and the results show that the thermal efficiency of second pattern was 2.12 percent less than the first pattern. Finally steady state thermal model was proposed to predict the efficiency of the collector, the comparison of experimental results and theoretical model was determined which showed that the model is capable to predict the collector efficiency in different conditions. Keywords : Solar energy, Facade collectors, Nanoparticle, Absorber plate colour, Thermal model.