  In this paper, we study the preheating duration modeled by an e-folding
number $N_{\rm pre}$ and an effective equation-of-state parameter $\omega_{\rm
pre}$. We show that a preheating equation-of-state parameter $\omega_{\rm pre}
= 0$ implies more post-inflationary e-folds of expansion. Considering the Higgs
and polynomial potentials, we conclude that the chaotic and the Higgs models
show good compatibility with the observational data according to the Planck
2018 results.
