Thermal modelling was carried out for typical new houses to identify the conditions under which the higher than Code schedule method insulation levels are cost-effective in new housing.
Generally, current Code levels are considered cost-optimal, but a number of situations were identified where extra insulation is worthwhile. These included polystyrene insulation under the concrete slab and the provision of a thermal mass wall with whole-house heating.
The type of heating appliance was found to have a significant effect on the cost-effectiveness of additional insulation. The base case heating schedule was 21°C from 5pm to 10pm during winter in the living/family rooms and spaces open to them (i.e. open-plan living, kitchen and dining room).