  We study the radiation of gravitational waves by self-gravitating binary
systems in the low-energy limit of Horava gravity. We find that the predictions
for the energy-loss formula of General Relativity are modified already for
Newtonian sources: the quadrupole contribution is altered, in part due to the
different speed of propagation of the tensor modes; furthermore, there is a
monopole contribution stemming from an extra scalar degree of freedom. A dipole
contribution only appears at higher post-Newtonian order. We use these findings
to constrain the low-energy action of Horava gravity by comparing them with the
radiation damping observed for binary pulsars. Even if this comparison is not
completely appropriate - since compact objects cannot be described within the
post-Newtonian approximation - it represents an order of magnitude estimate. In
the limit where the post-Newtonian metric coincides with that of General
Relativity, our energy-loss formula provides the strongest constraints for
Horava gravity at low-energies.
