About the Houses
The test houses were specified with R2.0 wall insulation plus reflective foil laminate (RFL) and R5.0 ceiling insulation.
Although the insulation is in excess of the current NCC requirements, these insulation levels were implemented so that non-window heat transfer would be minimised, thus accentuating the sensitivity of the houses to window performance.
The results would not be credible if the houses were under-insulated to start with. Except where noted, all houses had concrete slab-on-ground floors, brick veneer external walls and plasterboard internal partitions. It is well known that, for a given house, its annual energy performance for heating and cooling depends on its orientation. To account for this, each house was simulated four times with the house rotated progressively around the four cardinal directions. This yielded an average performance for the climate zone.