NatHERS 6 Star Energy Ratings can only be done on a whole of house modelled design, meaning that they are not ideal for additions and alterations where only the new and/or altered part of the building needs to comply with current building standards.
There is no requirement to upgrade existing areas of the dwelling or to construct the additions and/or alterations to a level where the whole house now achieves a 6 Star Energy Rating.
For this reason, the DTS Elemental Provisions are the usual go-to option for compliance reporting for additions and alterations.
In Western Australia, a performance solution protocol has been created called the WA Additions and Alterations Protocol. It is a two-part protocol, one part which can be done using the DTS Elemental Provisions and the other using a HERS modelling option.
The Protocol calculates the thermal requirements based on an area-weighted average between the existing dwelling and the new and/or altered part of the dwelling, taking into account the energy efficiency requirements at the time the existing building was constructed.
To find out more about compliance reporting for additions and alterations, or to arrange compliance reporting for your property, contact us below.