We compute the dissipation due to the drag of falling raindrops and cloud droplets, and find both to be significant sources of dissipation on Earth and possibly Titan. On other planets, they appear to be insignificant. We compare this dissipation with the latent heat transported by the drops and the thermodynamic efficiency with which it can be converted into work. This comparison suggests moist convection on Earth and Titan is similar, but on Jupiter latent heat alone does not provide enough work to lift the condensate against gravity.