In this paper we applied multi-criteria methods of decision in order to establish the best encapsulation material to be used in
producing photovoltaic modules. The encapsulation materials play an important role in establishing the PV module performance,
especially if referring to their ability to increase their life time. For our study, we have considered the most widely used
encapsulation materials available on the market, such as Ethylene-Vinyl Acetate (EVA), Polyvinyl Butyral (PVB), Thermoplastic
Polyurethane (TPU), PolyDimethylsiloxane (PDMS), Ionomer. Amongst of their basic properties, we took into consideration the
light transmittance, refractive index, thermal conductivity, volume resistivity, and water vapor transmission rate. In the paper
herein, two multi-criteria methods, namely the Simple Additive Weighting method and ELECTRE (ELimination and Choice
Expressing Reality) method are applied in order to establish a hierarchy of the mentioned encapsulation materials. It is also
shown that the final hierarchy of materials depends on the importance given to the criteria involved. By considering all the
mentioned properties and the economical aspect, in particular the cost, the first position in the hierarchy is occupied by EVA. If
the cost is eliminated, the hierarchy changes and EVA becomes outranked by other materials, as PDMS and Ionomer.