Models and observations indicate that the efficiency of driving energetic winds and the momentum fluxes of galaxy-scale outflows increases with AGN luminosity: indeed understanding the coupling between the nuclear energy output and the host galaxy is an issue particularly relevant for the most luminous quasars. We have analyzed the spectral energy distribution of the WISE/SDSS-selected hyper-luminous (log LBol > 47.3) quasar (WISSH) sample. Through multi component SED fitting we have been able to disentangle the different contributions of the nuclear source and of the host galaxy and derive relevant physical quantities such as extinction, AGN bolometric and monochromatic luminosities, Eddington ratios and SFR. I will present the results of this work, with particular focus on the 16 WISSH quasars for which a broad-band coverage is available up to the FIR thanks to the Herschel/SPIRE photometric data.