Existing Home Energy Rating vs DTS | Certified Energy

A Home Energy Rating assesses an existing dwelling and helps describe its thermal performance, whole-of-home energy use, installed systems and current performance characteristics.

DTS, or Deemed-to-Satisfy, is an NCC compliance pathway. It is used where proposed building work follows provisions or recognised assessment methods that are deemed to satisfy the relevant Performance Requirements.

A Home Energy Rating certificate for an existing dwelling cannot be used as evidence that proposed building work complies with the NCC.

DTS documentation does not provide a general rating of how the retained existing home performs for comfort, energy use or upgrade potential.

A renovation may involve both pathways: one to understand the current home and another to demonstrate compliance for the proposed works.

 

 

A Home Energy Rating examines an established dwelling as it has actually been constructed and fitted out.

The assessment is not based solely on the original architectural drawings. Available plans may assist, but the rating needs to reflect the real home, including alterations, installed products and systems that may have changed since construction.

Depending on the assessment scope, relevant information may include:

• dwelling location, orientation and climate;
• roof, wall and floor construction;
• insulation levels and installation conditions;
• windows, glazing and frames;
• fixed external shading;
• heating and cooling systems;
• hot-water systems;
• lighting and major fixed appliances;
• solar generation and battery storage;
• observable comfort or performance issues; and
• potential areas for future improvement.

The resulting certificate can include information about thermal performance, predicted household energy use, renewable energy and the home’s likely comfort without mechanical heating or cooling.

Its role is to establish a clearer performance picture of the existing property. It is not an approval document for new construction.

Explore the full existing-home framework in the Home Energy Rating Knowledge Hub.

 

Deemed-to-Satisfy provisions are recognised ways of satisfying relevant NCC Performance Requirements.

The project team can use an applicable DTS pathway where the proposed building solution follows the relevant provisions, assessment method and jurisdictional requirements.

For residential energy efficiency, the compliance evidence may relate to matters such as:

• roof, wall and floor construction;
• insulation and thermal bridging;
• windows and glazed doors;
• external shading;
• building sealing;
• heating, cooling and service provisions;
• whole-of-home energy requirements; and
• other measures required by the applicable NCC edition or jurisdiction.

DTS is broader than one residential energy report. It describes a compliance approach used across the NCC.

Within residential energy compliance, an elemental DTS pathway may apply prescribed provisions directly to individual building elements. A recognised NatHERS pathway may also form part of a DTS Solution for eligible new homes or major renovations.

For the wider residential compliance framework, visit the Residential DTS Knowledge Hub.

 

The simplest way to distinguish the pathways is to identify the subject of the assessment.

A Home Energy Rating is concerned with the home that exists today. It asks how the dwelling performs with its current construction, windows, insulation, appliances and energy systems.

DTS compliance is concerned with a proposed building solution. It asks whether new or altered work follows the relevant prescribed provisions or recognised DTS assessment method.

This distinction remains important even when both assessments relate to the same address.

A homeowner may receive a Home Energy Rating for the existing dwelling and still need separate compliance documentation for an extension, upper-level addition, garage conversion or other approval-related work.

 

Yes. A renovation can involve an assessment of the existing dwelling and a separate compliance pathway for the proposed works.

The two pieces of work may inform each other, but they remain distinct.

The existing-home assessment may support better renovation decisions. The compliance assessment provides the evidence required for the proposed building work.

For more detail on the construction boundary, see Residential DTS for Alterations and Additions.

 

 

A Home Energy Rating does not replace compliance documentation

A strong existing-home rating does not establish that an extension, alteration or conversion complies with the NCC.

Where proposed work requires approval, the applicable compliance documentation must still be prepared through the correct jurisdictional pathway.

DTS compliance does not replace a Home Energy Rating

DTS evidence confirms that the proposed solution follows the applicable prescribed provisions or recognised DTS method.

It does not provide a complete performance assessment of the retained home, a whole-of-home certificate or a structured review of broader upgrade opportunities.

 

 

Start with a Home Energy Rating when the primary question is:

• How does this existing dwelling perform now?
• Why is the home difficult to heat or cool?
• What are the current thermal and whole-of-home energy characteristics?
• Which areas may deserve further upgrade investigation?
• Do I need a rating for a property, lending or portfolio program?

Start with a compliance pathway review when the primary question is:

• Does this proposed building work comply with the NCC?
• Can the design follow elemental DTS provisions?
• Does the project need NatHERS, BASIX or another pathway?
• What evidence is required for building approval?
• Which requirements apply to the proposed extension or alteration?

 

Is a Home Energy Rating an NCC compliance certificate?

No. A Home Energy Rating for an existing dwelling describes the home’s current energy performance. It cannot be used as evidence that proposed building work complies with the National Construction Code.

Is DTS a home energy rating?

No. DTS is a National Construction Code compliance approach. It confirms that a proposed building solution follows applicable prescribed provisions or recognised DTS methods. It does not provide a general performance rating of an established dwelling.

Can NatHERS be part of DTS compliance?

Yes. A NatHERS assessment for an eligible new home or major renovation can form part of a recognised residential DTS compliance pathway. This is different from a Home Energy Rating prepared for an existing dwelling.

Can a renovation require both assessments?

Yes. The owner may use a Home Energy Rating to understand the retained dwelling, while the proposed renovation follows a separate NCC compliance pathway for the new or altered work.

Does a Home Energy Rating require original architectural plans?

Original plans are helpful but are not always available for existing homes. Photos, property information, measurements, renovation records and details of installed systems may also support the assessment. The assessor can confirm what further information is needed.

Does DTS assess the comfort of the existing house?

Not as a general existing-home performance assessment. DTS documentation is prepared to demonstrate compliance for the relevant proposed building solution. It does not replace a structured assessment of the retained dwelling’s current comfort and energy use.

Does the whole existing home need to meet the current NCC during a renovation?

Not automatically. Current requirements commonly apply to new or altered work, although existing elements may need to be considered because of the jurisdiction, approval decision, project scope or selected assessment method.

What should I do when I am unsure which assessment applies?

Provide the property address, available existing information and any proposed renovation drawings. An initial review can then distinguish between an existing-home performance assessment and a compliance requirement for proposed building work.

Home Energy Rating Knowledge Hub

Understand how existing-home assessments review current thermal performance, whole-of-home energy use and property information.

What Is a Home Energy Rating?

Read the foundational guide to the purpose, scope and assessment of an established Australian dwelling.

DTS for Alterations and Additions

See how proposed extensions, conversions and altered work may interact with residential compliance requirements.