  Heusler type compounds have long been recognized as potential thermoelectric
(TE) materials. Here, the experimentally observed TE properties of Fe$_{2}$VAl
are understood through electronic structure calculations in the temperature
range of $300-800$ K. The observed value of $S$ is $\sim-$138 $\mu$V/K at 300
K. Then, the $|S|$ decreases with increase in temperature up to the highest
temperature with the value of $\sim-$18 $\mu$V/K at 800 K. The negative sign of
$S$ in the full temperature window signifies the dominating $n$-type character
of the compound. The temperature dependent of electrical conductivity, $\sigma$
(thermal conductivity, $\kappa$) exhibits the increasing (decreasing) trend
with the values of $\sim$1.2 $\times$ 10$^{5}$ $\Omega^{-1}$m$^{-1}$
($\sim$23.7 W/m-K) and $\sim$2.2 $\times$ 10$^{5}$ $\Omega^{-1}$m$^{-1}$
($\sim$15.3 W/m-K) at 300 K and 800 K, respectively. In order to understand
these transport properties, the DFT based semi-classical Boltzmann theory is
used. The contributions of multi-band electron and hole pockets are found to be
mainly responsible for the temperature dependent trend of these properties. The
decrement of $|S|$ and increment of $\sigma/\tau$ $\&$ $\kappa_{e}/\tau$
($\tau$ is relaxation time) with temperature is directly related with the
contribution of multiple hole pockets. Present study suggests that DFT based
electronic calculations provide reasonably good explanations of experimental TE
properties of Fe$_{2}$VAl in the high temperature range of $300-800$ K.
