Cosmological measurements are placing the best upper bounds on the sum of the neutrino masses. Even more, a detection is currently promised by experiments such as EUCLID, which is already taking data. However, these results are model dependent and are relaxed if new physics in the neutrino sector exists. In this context, we present a framework to disentangle the different effects on neutrino masses on cosmology in a model independent manner. Using this technology, we can quantitatively understand through which properties do neutrino masses modify the CMB. This allows us to understand better what do the present cosmological bounds mean, and implement a consistency check for the neutrino mass measurement in cosmology.