This work investigates the reduction of power consumption in Networks-on-Chip through the reduction of transition activity using data coding schemes. Power macromodels for NoC and encoding modules were built, allowing the estimation of the power consumption as a function of the transition activity at each module input. Power macromodels are embedded in a system model and a set of simulations are performed, analyzing the trade-off between the power savings due to coding schemes versus the power consumption overhead due to the encoding and decoding modules.