What Information Is Needed for an All-Electric Home Design Review?

The information required depends on the project, assessment scope and applicable residential compliance pathway.

For a proposed new home, an initial package commonly includes architectural drawings, site information, construction specifications, glazing details and information about relevant household energy systems.

Where a NatHERS Whole of Home assessment or BASIX assessment is required, the nominated heating and cooling, hot water, cooking, solar and other relevant systems may need to be documented.

Existing-home projects require a different evidence base, including information about the dwelling as built. The assessor should confirm the specific information needed before the review begins.

Before gathering detailed technical information, the project team should establish what type of review is being requested.

A proposed new dwelling may require a NatHERS thermal performance assessment, NatHERS Whole of Home assessment, BASIX documentation or another applicable compliance assessment.

An existing home may instead require an existing-home energy assessment to understand current modelled performance or inform improvement planning.

The initial project information should identify the site address, project type, jurisdiction, design stage and intended assessment outcome.

It is also useful to nominate the primary project contact and identify whether drawings and specifications are preliminary, coordinated or issued for a particular approval stage.

Architectural drawings provide the basis for understanding the proposed building geometry and layout.

Depending on the assessment, useful drawings may include site plans, floor plans, elevations, sections and relevant roof information.

Drawings should identify dimensions, room arrangements, openings, levels and other features needed to interpret the dwelling.

Site orientation and relevant shading conditions may also affect thermal performance modelling.

Where architectural drawings are still being developed, the assessor may be able to identify information gaps or assumptions requiring confirmation. However, the assessment cannot be more definitive than the information available to support it.

A coordinated drawing set with a clear revision number is generally more useful than multiple documents containing conflicting layouts or specifications.

Building fabric information helps establish the thermal characteristics of the dwelling.

Relevant details may include wall, roof, ceiling and floor construction, insulation locations and nominated insulation performance.

Where different construction systems are used across the dwelling, those variations should be identified.

The assessor may also require clarification of elements such as exposed floors, adjoining spaces, thermal boundaries or other construction conditions that affect modelling.

Generic statements such as "insulation to comply" may not provide sufficient information for an assessment that requires specific construction and thermal performance inputs.

Windows and glazed doors can have a significant influence on modelled residential thermal performance.

The design package should identify opening locations, sizes, orientations and relevant glazing specifications.

Depending on the assessment, the assessor may require information about glazing system performance, frame types and the characteristics of nominated products.

Fixed shading elements such as eaves, awnings, pergolas and other relevant building features should be clearly shown where they influence the assessment.

If glazing selections change after an assessment has been prepared, the project team should confirm whether the energy model or compliance documentation needs updating.

Where heating and cooling systems form part of the relevant assessment, the project team should identify the proposed technology and available system details.

For an all-electric home, this may include reverse-cycle air conditioning or other electric heating and cooling arrangements.

The information needed depends on the applicable methodology and may include system type, efficiency characteristics, configuration and areas served.

If exact equipment has not yet been selected, the assessor should be advised rather than given an unsupported product assumption.

An energy assessment may model nominated heating and cooling systems, but it does not determine the required equipment capacity or replace specialist mechanical design.

Hot water and cooking systems can form part of the household energy information required for relevant residential assessments.

The project team should identify whether hot water will be provided by a heat pump, electric resistance system or another proposed technology.

Where required by the assessment methodology, additional product or performance information should be provided.

Cooking information may include the proposed cooktop technology and other relevant details requested by the assessor.

The purpose is to document the nominated household systems accurately, rather than to substitute an energy assessment for specialist equipment selection or installation design.

For additional design context, see our guide to heat pump hot water in new homes.

Where rooftop solar or battery storage is proposed, the project team should identify the intended arrangement and available specifications.

Depending on the assessment, relevant information may include the proposed solar photovoltaic system capacity, orientation, configuration or other characteristics required by the methodology.

Battery information should be provided where relevant to the assessment scope and supported by the applicable modelling method.

Proposed electric vehicle charging should also be identified as part of wider project coordination, although its treatment in energy assessment software depends on the specific methodology.

Providing this information does not remove the need for separate electrical design, network connection advice or installation approval where applicable.

Not every residential energy assessment uses the same information.

A NatHERS thermal performance assessment focuses on the dwelling's modelled heating and cooling requirements based on building design and thermal characteristics.

NatHERS Whole of Home separately considers specified household energy systems under the applicable methodology.

This means a design package that is sufficient for an initial thermal assessment may still need additional information about heating and cooling equipment, hot water, cooking or other relevant systems for a Whole of Home assessment.

The assessor should confirm the specific inputs required for the selected software and assessment pathway.

For applicable projects in New South Wales, existing BASIX documentation can provide important context for the assessment.

If a BASIX certificate or earlier assessment has already been prepared, the project team should provide the current version and identify any design changes made since its issue.

Differences between architectural drawings, nominated systems and existing compliance commitments may require clarification or reassessment.

For projects outside NSW, the relevant residential energy compliance pathway and documentation requirements should be established according to the applicable jurisdiction.

The objective is to ensure that the information used for the energy assessment corresponds with the design being submitted or constructed.

An existing-home energy assessment differs from a design-stage assessment because the dwelling has already been constructed.

Available plans, renovation records, insulation information, glazing details and equipment specifications may help establish the property's current characteristics.

However, documentation may be incomplete or may not accurately reflect the dwelling as built.

The applicable assessment methodology may therefore require an inspection, observations, measurements or other evidence collected by an appropriately qualified assessor.

Where electrification upgrades are proposed, it is useful to distinguish between existing equipment and future intended replacements.

See NatHERS Existing Homes for further information about the existing-dwelling assessment context.

Not every project begins with a fully resolved design package.

Where information is missing, the assessor may request clarification, identify provisional assumptions or explain which inputs are required before the assessment can proceed.

Some changes can affect modelled performance or compliance outcomes. Examples may include changes to glazing, insulation, building geometry or nominated household energy systems.

The project team should communicate material design changes and provide updated documentation where required.

Clear version control helps ensure that the energy assessment corresponds with the current design rather than an earlier superseded drawing set.

Consider a proposed all-electric home with reverse-cycle heating and cooling, heat pump hot water, induction cooking and rooftop solar.

The architect has completed the main drawings, but several equipment selections remain provisional.

The project team provides the latest architectural drawings, construction specifications, glazing information and the intended household system types.

The assessor reviews the information against the relevant assessment requirements and identifies which additional specifications are needed to complete the modelling.

As equipment selections are confirmed, the project team supplies updated information and checks that the assessment and design documentation remain aligned.

This illustrates how an organised information package can support assessment progress without requiring every specialist installation detail to be resolved at the outset.

Do I need completed construction drawings before requesting an energy assessment?

Not necessarily. An initial assessment may be possible using sufficiently developed design information. The assessor should confirm which drawings and specifications are required for the intended assessment stage and final deliverable.

Do I need to select every electric appliance before a Whole of Home assessment?

The required level of detail depends on the applicable assessment methodology. Where equipment selections are provisional, this should be disclosed so the assessor can identify suitable next steps and any information needed before finalisation.

Are electrical drawings required for a NatHERS assessment?

A NatHERS thermal performance assessment does not ordinarily require a complete electrical installation design. Information about relevant household systems may be required for Whole of Home modelling. Electrical design and capacity assessment remain separate professional responsibilities.

What if the hot water or heating system changes after assessment?

The project team should advise the assessor of the change. Depending on the assessment scope, methodology and applicable commitments, updated modelling or compliance documentation may be necessary.

Can an existing home be reviewed without original architectural drawings?

Potentially. Existing-home assessment methodologies may use observations, measurements and other evidence collected during an assessment. The required process depends on the particular rating or assessment service.

Can Certified Energy confirm what information is needed for my project?

Certified Energy can identify the information required for a relevant residential energy performance or compliance assessment once the project type and intended scope have been established. Separate specialist documentation may be required for electrical, mechanical, hydraulic or other design work.