Manage Demand: Thermal Performance

The way that a building is designed and built has a huge impact on the amount of heat that flows in and out – and on how much heat is retained in the building fabric.  This impacts directly on the comfort of the building – how useable it is for residents/ users and for staff.  This also impacts directly on how expensive the building is to operate.

Thermal performance of a building covers four key areas:

  • Insulation: preventing or minimising heat from flowing through the walls, floors, ceilings
  • Glazing: preventing or minimising heat from flowing through windows and window coverings
  • Draught proofing: preventing air from flowing in and out of the building where it’s not wanted – while ensuring that the airflow does occur when it is wanted (ventilation)
  • Thermal mass: capturing heat when it’s wanted and reducing the rate of change of building temperature

Thermal performance is intrinsically linked to the building’s heating, cooling and ventilation systems.  As a building’s thermal performance is improved, its requirement for active heating and cooling is reduced.  In southern Victoria we have such a benign climate – most of the time – that a well designed and built building should need zero active heating or cooling.  An office building will probably need some cooling on the hottest days of summer.  But in a really well insulated, passive solar gain building, you should be able to avoid significant need for winter heating.

A key point in the above is “design”.  We regularly see buildings which meet modern design standards – they may even be “5 star” – but which simply don’t work very efficiently.  Many architects are fabulous at designing buildings which look great … but a long way from ideal in terms of thermal performance.  To make matters worse, short cuts taken during the building process may leave areas which have been specified to be properly insulated … only half insulated.  Rushed installs or shoddy workmanship may leave insulation batts lying in stacks rather than properly laid out and eliminating gaps.

Good thermal design.  Good attention to detail during construction.  Good checking before the roof and walls are sealed up.  It’s not hard but it does not happen often enough.