In view of the imminent publication/adoption of a revised and expanded section G6 of the NZBC it is timely to consider how accurately we can confirm the acoustical performance of buildings by objective measurement. An obvious extension of this is to consider how our measurements (and their associated accuracy) match up with our ability to subjectively detect changes in the quality of building insulation. This has implications for how we might advance from a concept of a simple pass/fail for buildings based on a minimum building performance (i.e. specified in G6) to a set of categories of acoustic comfort for guiding both designers and (with reliable verification) prospective occupiers. In research to develop techniques for screening the performance of buildings we consider the possibility of measuring the impact insulation of floors by an alternative to the standard tapping machine plus a full ISO 10140 procedure. The success of such techniques depends on the saving in measurement effort and the increase in uncertainty they involve.