House Energy Ratings

To achieve an energy rating on a residential dwelling (Class 1), House Energy Rating Software (HERS) is best used for assessing the thermal performance for the job. The software will simulate a home and provide estimates for the energy needed to heat or cool that dwelling over the course of the year.

First Generation House Energy Rating Software has since been superseded, in 2009, by Second Generation software.

This Second Generation House Energy Rating Software has been tightened and improved, meaning that software has become more precise, accurate and powerful in it's responses.

The Second Generation software must now take into account more features and realistically model elements such as natural ventilation, the cooling effects of ceiling fans, under-floor heating and the effects of attached dwellings such as apartments.

It also zones the dwelling in to areas of use which helps identify the rooms that have the major heating and cooling problems.

Thermal Performance

The thermal performance in a residential building is a dwelling's ability to stay naturally cool in summer and naturally warm in winter. House Energy Rating Software evaluates the thermal efficiency of a new dwelling's design with the thermal comfort level set at around 20ºC to 22ºC for Australia.

The resulting Thermal Performance Assessment is then given a star rating between 0 to 10 stars, the higher the stars the better the thermal performance. Here are a couple of examples:
• If the assessment only achieves 3 stars then there is a greater need for the use of heating and/or cooling energy to achieve one's comfort level, more running costs to the owner.
• If the assessment achieves 6 stars plus then there is a lesser need for the use of heating and/or cooling energy to achieve one's comfort level, a lesser cost to the owner.



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