  We have incorporated our experimentally derived thermal rate coefficients for
C + H$_3^+$ forming CH$^+$ and CH$_2^+$ into a commonly used astrochemical
model. We find that the Arrhenius-Kooij equation typically used in chemical
models does not accurately fit our data and use instead a more versatile
fitting formula. At a temperature of 10 K and a density of 10$^4$ cm$^{-3}$, we
find no significant differences in the predicted chemical abundances, but at
higher temperatures of 50, 100, and 300 K we find up to factor of 2 changes.
Additionally, we find that the relatively small error on our thermal rate
coefficients, $\sim15\%$, significantly reduces the uncertainties on the
predicted abundances compared to those obtained using the currently implemented
Langevin rate coefficient with its estimated factor of 2 uncertainty.
