solaRate specialises in thermal performance assessments (energy ratings) for all types of residential developments, including:

  • New homes
  • Extension to existing homes
  • Multi-residential developments

We are accredited in the use of FirstRate5 software for energy ratings

Energy Efficiency Performance requirement for residential buildings

The National Construction Code (NCC) provides a number of options to demonstrate compliance with Energy Efficiency performance requirements.

Class 1 Buildings

  • Deemed to Satisfy (DtS) - NCC Elemental Provision approach
  • Deemed to Satisfy (DtS) - Energy Rating approach.  New Class 1 buildings must achieve a minimum of 6 Star Rating and have either a rainwater tank or a solar water heater system installed.
  • Alternative Solution - Verification Method V2.6.2.2 using a Reference Building approach

Class 2 Buildings and Class 4 part of a building

  • Class 2 buildings must achieve an average of 6 Star Rating collectively for all sole-occupancy units (SOU) and not less than 5 Star Rating for each individual SOU.
  • Class 4, part of a building, must achieve a minimum of 6 Star Rating.

Residential Energy Compliance Approaches offered by solaRate

Deemed to Satisfy (DtS) - NCC Elemental Provision approach

DtS solution involves checking the individual elements of a building against a standard set of parameters (Performance Requirements) that meet the NCC requirements.  These elements are broken down into the following categories:

  • Building Fabric
  • Glazing
  • Air Movement
  • Sealing
  • Services

The DtS solution only looks at each building element in isolation and does not allow for “trade-offs” between building elements.  Such as increasing the insulation levels in the roof, walls and floor above the minimum Performance Requirement to allow the use of lower thermally performing glazing.

Deemed to Satisfy (DtS) - Energy Rating approach

The energy rating method requires a building to achieve an energy rating of a minimum of 6 Stars using software (FirstRate 5, Accurate or BERS Pro) accredited under the Nationwide House Energy Rating Scheme (NatHERS).

This provides a more flexible and innovative compliance path allowing “trade-offs” between building elements.  The following two categories Sealing and Services are not addressed by the energy rating software and their Performance Requirements should be satisfied by the Elemental Provision approach.


Alternative Solution - Verification Method V2.6.2.2 using a Reference Building approach

The intent of the Verification Method is to demonstrate that a Performance Solution meets the appropriate Performance Requirement(s) of the NCC.

The basic approach is that the annual heating load and/or cooling load (typically measured in MJ/m2/annum) of the proposed building must not be more than the annual heating load and/or cooling load target of a complying theoretical reference building using the DtS (Deemed to Satisfy) Provisions.

This establishes the theoretical annual heating load and/or cooling load that would have been generated by that house’s design had it been built to comply with the DtS Provisions. This sets a quantified target (benchmark) that must be achieved when modeling the Performance Solution.

This approach requires two modeling runs with software; the first to set the heating load and/or cooling load targets (i.e. using the reference building described above) and the second to demonstrate that the proposed building can achieve this minimum target. The same calculation method, commonly an energy rating tool, is used in both modeling runs to maintain consistency.

The Verification Method V2.6.2.2 allows certain “trade-offs” between different elements of the building fabric, such as a reduction of insulation in the walls whilst increasing the insulation in the roof or improving the thermal performance of the glazing. This method also allows for flexibility in the design of the glazing (size, openability and thermal performance), shading, the sealing of the building envelope (walls, floors and roof) and air movement.

This approach of compliance is particularly suited to designs which push the boundaries of normal design.


A software tool developed under the Nationwide House Energy Rating Scheme (NatHERS). FirstRate5 estimates your home’s future energy demands for heating and cooling.  The calculations consider your building’s orientation, thermal insulation and other major design attributes.  The higher the rating the less demand the building will have on mechanical heating and cooling therefore reducing operational energy demand.


  • The Building Designers Association of Victoria - BDAV
  • Association of Building Sustainability Assessors - ABSA
  • Nationwide House Energy Rating Scheme - NatHERS
  • Australian Building Codes Board - ABCB
  • Sustainability Victoria - SV
  • House energy rating software - FirstRate5
  • Window Energy Rating Scheme - WERS
  • Victorian Building Authority - VBA