How to hire a NatHERS energy assessor in Adelaide

The 10-step framework

1. STEP 1

   Confirm the NCC 2025 whole-of-home requirement

   Under the National Construction Code 2025, every new residential build in South Australia must demonstrate compliance with the whole-of-home performance requirements. NatHERS star rating (typically minimum 7 stars for the fabric) is one path to compliance; whole-of-home covers heating, cooling, hot water and pool pumping.

2. STEP 2

   Engage an accredited NatHERS assessor

   Only accredited assessors can issue NatHERS certificates. Accreditation is via one of three assessor accreditation bodies (ABSA, HERS, or DGP). Confirm accreditation before engagement.

3. STEP 3

   Book the assessor at working drawing stage

   The optimal engagement point is when working drawings are substantially complete but before building consent. Earlier engagement risks reassessment fees when design changes; later engagement risks discovering non-compliance too late.

4. STEP 4

   Provide the assessor with complete drawings

   The assessor needs: architectural plans (floor plans, elevations, sections), window schedule with sizes and orientations, wall and roof construction detail, insulation specifications, and the site plan showing orientation. Missing information delays the assessment.

5. STEP 5

   Understand the star rating scale

   Star ratings run from 0 (worst) to 10 (best net-zero energy). The NCC 2025 baseline is around 7 stars for the fabric. 8 stars represents meaningful uplift. 9 stars is significant. 10 stars is exceptional. Choose your target based on comfort ambition, not just compliance.

6. STEP 6

   Discuss whole-of-home vs fabric-only assessment

   A whole-of-home assessment covers appliances (heating, cooling, hot water, pool) as well as fabric. Fabric-only assessment is limited to the building envelope. Whole-of-home is now the compliance path under NCC 2025.

7. STEP 7

   Compare fees against scope

   A residential NatHERS assessment for a typical Adelaide new home ranges from a few hundred to just over a thousand dollars. Complex designs with unusual glazing or non-standard construction attract higher fees.

8. STEP 8

   Get a design-stage assessment before working drawings finalise

   Some assessors offer a design-stage advisory scope that identifies areas where the design can be optimised for star rating before working drawings lock in. Fees for advisory scope are modest and can save real money by catching issues early.

9. STEP 9

   Confirm the assessor reports the same specification the builder uses

   The star rating certificate is only valid if the built home matches the assessed specification. Any change to insulation, glazing or construction detail requires reassessment. Coordinate with the builder to ensure the built specification matches the assessed one.

10. STEP 10

    Understand the Passivhaus interaction

    For certified Passivhaus builds, the NatHERS assessment is still required for NCC compliance but is not the primary performance measure. Passivhaus uses PHPP modelling instead. Both certificates can coexist; discuss with your Passivhaus designer at engagement.

FAQs