Heusler-type Fe 2 VAl compound is a promising thermoelectric candidate with non-magnetic ground state. The present work investigates the Seebeck coefficient (S) of Fe 2 VAl in the temperature region 300 to 620 K with the help of experimental and theoretical tools. The experimental value of S is observed∼− 130 μV/K at 300 K. Afterthat, the magnitude of S decreases gradually as the temperature increases. At T= 620 K, the value of S is found to be∼− 26 μV/K. In order to understand the behaviour of the experimentally observed S value, the band-structure and density of states calculations are performed by using LDA, PBE, PBEsol, mBJ and SCAN within density functional theory. All the above mentioned exchange-correlation (XC) functionals (except mBJ) predict the semi-metal like behaviour of the compound, whereas the mBJ gives the indirect band gap of∼ 0.22 eV having the well agreement with experimentally observed value. The temperature dependence of S for Fe 2 VAl is also calculated with the help of all the five mentioned functionals individually. The best XC functional is investigated for searching the new thermoelectric materials by taking Fe 2 VAl as a case example through this study. The best matching between experimental and calculated values of S as a function of temperature is observed by setting the mBJ band gap with the band-structure of PBEsol or SCAN. Therefore, the present study suggests that the band-structure of PBEsol or SCAN with mBJ band gap can be used for searching the new thermoelectric materials.