The Role of Insulation in Energy Efficient Design

Insulation is an important part of any home because it reduces the flow of heat into the home during summer and out of the house during the cooler months. This is particularly important in cooler temperate areas like coastal NSW and southern Victoria where there are generally longer cold periods and shorter hot periods.

There are two types of insulation – bulk & reflective.

Bulk Insulation

Bulk insulation reduces the flow of heat by creating a "flow barrier" which inhibits heat flow from the warm side to the cool side. This type of insulation includes fibreglass batts, etc.

Reflective Insulation

Reflective insulation reduces heat flow through a building's roof and walls by reflecting radiant heat on the warm side. Radiant heat only travels through air (or a vacuum) so reflective insulation must have an air space adjacent to the reflective surface. This type of insulation includes silver foil sisilation products, etc.

Additional Notes

(a)  Windows

Glass is a very poor insulator. Therefore a well insulated home must also have "insulated" windows since they are generally a large proportion of the external wall fabric. The way to improve the insulation efficiency of windows is to use double glazing.

(b)  Floors

There are basically two types of floors – timber on stumps, bearers & joists and a concrete slab.

In climates with very cold periods (e.g. Alpine areas) concrete slabs and timber floors should be totally insulated. In cool temperate regions (e.g. southern Victoria) at least the perimeter of a concrete slab should be insulated. Again the whole timber floor should be insulated.