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Improving home energy star ratings


I am familiar with the Star Rating on appliances, is the Star Rating of my home similar?

Yes, it is similar. The Star Rating on the appliance relates solely to that appliance.

The Star Rating of your home assesses how much energy is used to cool and heat your home to keep it comfortable all year long. Understandably, the Star Rating of your home involves a significant number of variables and computer simulations are used that calculate the temperature of the air in every room of the entire dwelling for every hour of every day for an entire year.

The computer simulations identify which rooms get hotter and colder than others and pinpoints any problem areas where improvements can be made.

The Star Rating of homes can range from 0 to 10 stars.

What is an Energy Rating Assessment?

An energy rating assessment looks at how effective the building fabric is at maintaining a comfortable living environment in a house or other type of residential dwelling.

The building fabric of a dwelling includes its roof, ceiling (including ceiling lights), walls and floor. It is the fixed elements of the dwelling which are measured rather than things such as appliances, taps, shower heads etc.

The orientation and climate zone of the dwelling are also taken into consideration.

The energy efficiency of a dwelling is represented as a Star Rating. This rating is based on the amount of energy required to heat or cool the home to a comfortable temperature all year long.

What information do I need to provide for the energy assessment to be done for my new home?

The minimum design documentation to enable a rating assessment to be done is –

  • Site Plan (including details of adjacent buildings)
  • Floor Plans including floor coverings
  • Elevations
  • Sections
  • Lighting Plan (including details of recessed luminaires)
  • Location and type of (operable or not) exhaust fans
  • Window schedule including window types (sliding, awning or specialised glass)
  • Details of construction materials
  • Clear North point
  • Helpful additional information would include roof colour, insulation (floor, walls, ceiling and roof), solar panels, ceiling fans, roof space ventilation etc.

If information such as adjacent buildings or lighting layout plans are not provided, then worst case scenarios are required to be modelled which may adversely affect your rating.

It is always better to provide as much detail as possible. Please ask us about detailed Checklist.

Who is able to provide an Energy Rating Report?

A Thermal Performance Assessor (NatHERS Assessor) certified by ABSA is required to confirm the energy rating of a house and legally provide the required documentation to the relevant authorities.

How long will the Assessment take?

For Thermal Performance Assessments of new single dwelling, dual occupancy and town house developments, our turnaround is normally one week depending upon current workload and the complexity of the design. Rush jobs are available for an additional investment – please contact us if you need a priority turnaround to meet a certain deadline.

With assessments of existing dwelling, a site inspection and measure-up is required, so our turnaround is slightly longer at 10 working days.

What are the benefits of having a Thermal Performance Assessment undertaken on my home?

A Thermal Performance Assessment gives you valuable information on the amount of energy used to cool and heat your home to keep it comfortable all year long. The computer simulations identify which rooms in your home get hotter and colder than others. With this information, you are in a strong position to make informed decisions on exactly where to invest most effectively in your home to make your home more comfortable, cheaper to run and better for the environment.