Home Electrification During Design: What Should Be Decided Early?

Home electrification is often approached as a decision about replacing gas appliances with electric alternatives. For new residential projects, however, the implications extend beyond the appliances themselves. Heating, cooling, hot water, cooking and future electricity demand can influence building layouts, service coordination, equipment locations and energy assessment documentation.

These requirements are generally easier to consider while a design remains flexible. Once architectural layouts, equipment specifications and construction documentation have progressed, changing a household energy system may involve additional coordination or redesign.

For architects, building designers, developers and homeowners, the useful starting point is to identify which electrification decisions affect the proposed dwelling and when those decisions should be resolved.

Early electrification planning is not about selecting every appliance immediately. It is about identifying the building and infrastructure decisions that become harder to change later.

Early design decisions should establish whether the dwelling will be all-electric, which household energy systems are proposed and whether those systems introduce requirements for equipment space, electrical infrastructure or building services.

Heating and cooling decisions should be considered alongside insulation, glazing, shading and other characteristics that influence thermal demand.

Hot water equipment locations, electrical supply requirements and opportunities for rooftop solar may also need to be coordinated before plans are finalised.

Relevant residential energy assessments, including NatHERS, NatHERS Whole of Home and BASIX for applicable NSW projects, should be considered alongside the proposed building and equipment specifications.

The objective is to identify important design constraints early while retaining flexibility for equipment choices that can reasonably be resolved later.

Technical and compliance note: Residential energy requirements depend on the applicable NCC edition, jurisdiction, building classification and assessment pathway. Energy performance assessments do not replace electrical design, equipment installation requirements or specialist heating and cooling system sizing. Electrical infrastructure and installation requirements should be assessed by appropriately qualified professionals.

Many electric household systems can be incorporated into conventional residential designs without unusual construction arrangements.

Difficulties are more likely when important equipment and infrastructure requirements are identified after relevant design decisions have already been made.

For example, changing from gas hot water to a heat pump system may require a different equipment location, additional installation clearances or revised electrical provisions.

A late change to heating and cooling equipment may affect outdoor unit locations, internal space allowances, service routes or architectural details.

These changes are not necessarily complex, but they can become more disruptive when equipment locations, external elevations and service arrangements have already been documented.

Considering electrification early allows project teams to identify relevant requirements while there is still flexibility to coordinate them.

One of the earliest decisions is whether the dwelling will use electricity for its normal household energy services or retain gas-powered equipment.

An all-electric strategy may involve reverse-cycle heating and cooling, electric hot water, induction cooking and other electrically powered household systems.

Rooftop solar, battery storage and electric vehicle charging may also form part of the proposed or future household energy arrangements, although they are not prerequisites for an all-electric home.

Confirming the intended approach helps the design team identify equipment requirements and coordinate assumptions between architectural, electrical and energy assessment documentation.

The broader relationship between household systems and energy performance is explained in the Home Electrification Knowledge Hub.

Different household systems create different design considerations. The following table identifies common areas for early coordination rather than prescribing a particular technology or installation arrangement.

Electrification does not remove the importance of thermal performance.

The heating and cooling energy required by a dwelling depends on characteristics including orientation, insulation, glazing, shading, air leakage and local climate conditions.

These characteristics influence the demand that the proposed heating and cooling systems must address.

For new homes, considering building fabric alongside the intended heating and cooling approach can help avoid treating mechanical equipment as a substitute for appropriate thermal design.

A NatHERS thermal performance assessment can help evaluate modelled heating and cooling energy requirements under standardised conditions.

This information is useful for understanding the building's thermal performance, but it does not replace the separate design and sizing of heating and cooling equipment.

Hot water system selection can affect more than the energy performance of a residential project.

Heat pump hot water systems can use substantially less electricity than conventional electric resistance systems under suitable conditions, but their installation requirements depend on the equipment selected.

Relevant considerations may include equipment dimensions, airflow clearances, noise, service access, electrical connections and the distance between the unit and hot water outlets.

Some installations may also benefit from considering how hot water operation could be coordinated with daytime solar generation.

Where hot water equipment is selected late, the proposed location may conflict with landscaping, access arrangements, external elevations or other building services.

Early planning does not require a final product selection in every case, but it should establish whether suitable space and infrastructure can be provided for the intended type of system.

An all-electric dwelling may require electrical infrastructure to support heating, cooling, hot water, cooking and ordinary household appliances.

Future electric vehicle charging, battery storage or equipment changes may introduce additional considerations.

The electrical requirements of these systems depend on their specifications, operating characteristics and the wider installation.

There is no single electrical supply or switchboard arrangement that applies to every all-electric home.

Electrical designers and appropriately licensed professionals should determine relevant supply capacity, maximum demand, circuits, protection and installation requirements.

For the wider project team, the early design task is to communicate the intended household systems and likely future requirements so electrical planning is based on realistic project assumptions.

Rooftop solar can support an all-electric home by supplying electricity to household loads during periods of generation.

The relationship between generation and demand depends on the household's operating patterns, equipment and available controls.

Hot water heating may be scheduled to coincide with solar production where the system permits it, while heating, cooling and vehicle charging may follow different demand patterns.

Battery storage may allow some generated electricity to be used later, although its suitability depends on installation costs, tariffs, demand and system configuration.

Early design considerations may include available roof area, orientation, shading, equipment locations and whether future system additions should be accommodated.

These considerations do not replace specialist solar or battery design. They help establish whether the building layout and service arrangements preserve practical options for future household energy systems.

Home electrification and residential energy compliance are related, but they are not the same.

A home can be designed as all-electric without automatically satisfying the energy performance requirements applicable to the project.

For new Australian residential projects, the relevant assessment requirements depend on the jurisdiction, building classification and compliance pathway.

NatHERS Thermal Performance

NatHERS thermal assessments model the heating and cooling energy required by the dwelling under standardised conditions. They help evaluate the influence of the proposed building design on thermal demand.

NatHERS Whole of Home

NatHERS Whole of Home models specified household energy systems, including heating, cooling, hot water, lighting, relevant appliances, solar generation and battery storage. Proposed equipment selections can influence the modelled assessment outcome.

BASIX in New South Wales

For applicable NSW residential projects, BASIX establishes sustainability requirements and commitments that may be affected by hot water, heating, cooling and solar selections.

Early coordination can help maintain consistency between architectural plans, equipment specifications and the assumptions used in relevant energy assessments. These assessments have distinct purposes and should not be treated as substitutes for electrical or specialist equipment design.

Not every electrification decision needs to be finalised at the same stage.

Some decisions affect building space, infrastructure and documentation and are more difficult to change later. Others can remain flexible until detailed design or procurement.

For example, a project may need to establish the intended hot water technology and installation location before finalising the building layout, without necessarily selecting the final equipment brand at that point.

The appropriate distinction depends on the project, but identifying these dependencies early can help avoid unnecessary commitments or late changes.

Consider a proposed new home where the preliminary design assumes a gas hot water system.

During detailed design, the owner decides to pursue an all-electric household energy strategy and considers replacing the proposed gas system with heat pump hot water.

The change may affect the equipment location, airflow clearances, electrical provisions and service access.

It may also require review of the hot water assumptions used in relevant residential energy assessment documentation.

If the change is identified while equipment space and service arrangements remain flexible, the design team can consider suitable options before the documentation is finalised.

This example illustrates the value of coordination. It does not mean a heat pump system will be suitable for every proposed location or that a late equipment change will always require substantial redesign.

Early electrification planning is most useful when the agreed decisions are reflected in the relevant project documentation.

Architectural plans, equipment schedules and energy assessment inputs should describe consistent building and household system assumptions.

For example, if an assessment relies on a particular hot water system type or heating and cooling specification, subsequent equipment changes may need to be reviewed for their effect on the assessment outcome.

Changes during detailed design or construction should not automatically be assumed to have no effect on previously prepared documentation.

Clear coordination helps project teams understand which decisions have been assessed, which remain provisional and when updated information may be required.

• Confirm whether the dwelling will be all-electric or retain any gas systems.
• Identify the proposed heating and cooling approach.
• Consider heating and cooling demand alongside building fabric design.
• Identify the intended hot water system type.
• Allow suitable equipment space, access and installation clearances.
• Consider the location and requirements of electric cooking equipment.
• Communicate expected electrical loads to the electrical designer.
• Consider potential future electric vehicle charging requirements.
• Review rooftop solar opportunities and relevant roof constraints.
• Consider whether future battery storage provisions are appropriate.
• Identify applicable NatHERS, Whole of Home and BASIX requirements.
• Confirm that relevant equipment assumptions are reflected in energy assessments.
• Coordinate architectural, electrical and mechanical design responsibilities.
• Identify decisions that must be resolved before construction documentation.
• Review later equipment changes for potential documentation implications.

When should electrification be considered in a new home design?

Ideally, during early design when the intended household energy strategy, equipment locations and infrastructure requirements can be coordinated before layouts and construction documentation are finalised.

Does every appliance need to be selected before design begins?

No. The important early decisions are those that affect building space, services, electrical infrastructure and assessment requirements. Some final equipment selections can remain flexible where appropriate allowances have been made.

Can an all-electric home still require changes to its energy assessment?

Yes. Changes to specified household systems may affect relevant modelled energy performance or compliance commitments. The implications depend on the applicable assessment and the equipment information used.

Does NatHERS determine which heating and cooling equipment should be installed?

No. NatHERS thermal performance assessments model heating and cooling energy requirements under standardised conditions. Detailed equipment selection and sizing require separate specialist consideration.

Should solar and battery storage be included in early design planning?

They may be relevant where the project intends to install these systems or preserve opportunities for future installation. Roof layout, shading, equipment space and electrical provisions can influence later options.

Can Certified Energy assess electrical supply capacity for an all-electric home?

Residential energy performance assessments do not replace electrical infrastructure assessment or design. Electrical supply capacity, switchboard requirements and installation safety should be addressed by appropriately qualified electrical professionals.