A standard proposal for rating airborne sound insulation in buildings [ISO 16717-1 (2012)] defines the reference noise spectra. Since their shapes influence the calculated values of single-number descriptors, reference spectra should approximate well typical noise spectra in buildings. There is, however, very little data in the existing literature on a typical noise spectrum in dwellings. A spectral analysis of common noise sources in dwellings is presented in this paper, as a result of an extensive monitoring of various noisy household activities. Apart from music with strong bass content, the proposed "living" reference spectrum overestimates noise levels at low frequencies.