BASIX, Solar and Batteries for a New Build in NSW: What the Certificate Needs, Sizing for an All-Electric Home, Timing With Your Builder and the Northern Rivers Exception

Checked and updated by our licensed electricians: October 2026

Every new home in NSW needs a BASIX certificate, and the solar, the hot water and the air conditioning you choose at plan stage decide whether it passes easily or expensively. The Northern Rivers has its own twist: our climate zones were left out of the 7-star standards that the rest of the state moved to in October 2023, so what your certifier asks for here is different from Sydney. This guide, written by local electricians who design solar and battery systems from builders’ plans, explains what the certificate needs, how rooftop solar and a heat pump score in it (and why a battery does not), how to size solar and a battery for an all-electric home, the single-versus-three-phase decision that has to be made before the slab, what to have the builder pre-install, and when in the build to quote, install and claim the rebates. The planner at the top turns your appliance choices into a solar size and a battery size in six taps. We are not BASIX certifiers; the builder and the assessor own the certificate, and we make the electrical design fit it.

On this page: The planner: solar and battery for your new home · What BASIX is and when you need it · The Northern Rivers exception to the 7-star rule · How solar, hot water and air conditioning score · The all-electric new build · Sizing: people, loads, winter, evening · Single or three phase: decide before the slab · Solar and battery ready: what the builder pre-installs · Timing with the builder, the certifier and the rebates · Questions we get asked

New build solar and battery planner

Six taps: people, hot water, cooking, heating and cooling, EV or pool, and single or three phase. The result shows on screen straight away, with the loads behind it and the list to give your builder; sending it to your phone is optional.

What BASIX is and when you need it

BASIX, the Building Sustainability Index, has been part of every NSW residential approval since 1 July 2004. A BASIX certificate is required for every new house and apartment, for alterations and additions with a construction cost of $50,000 or more, and for a swimming pool of 40,000 litres or more. It is generated online by the designer or an assessor, lodged with the development application or complying development certificate (within three months of issue), and its commitments are checked by the certifier before the occupation certificate. It has three parts:

• Thermal performance: how well the building shell keeps heat out in summer and in during winter, shown as NatHERS stars (or met by the simpler DIY method for standard designs).
• Energy: a required percentage cut in greenhouse emissions against a fixed benchmark of 3,292 kg of CO2 per person per year, worked out from the hot water system, heating and cooling, lighting, cooking, pool and spa equipment and any rooftop solar. The target varies with climate zone, dwelling type and floor area.
• Water: rainwater tanks, fixtures, landscaping and pool covers.

Since October 2023 the certificate also records the embodied emissions of the main materials, with no limit set yet. BASIX is not a solar rule and does not force a battery; it is a scorecard, and solar is one of the easiest ways to earn points on it.

The Northern Rivers exception to the 7-star rule

On 1 October 2023 NSW raised its BASIX standards to match the National Construction Code 2022: houses to 7 NatHERS stars (from an average of about 5.5 to 6), energy targets up by 7 to 11 per cent depending on location and dwelling type, a lower grid emissions factor (0.67 kg CO2 per kWh, a ten-year average to 2031) and efficient lighting assumed. Homes whose building contracts were signed before that date had until 30 September 2024.

Except here. The planning department excluded homes in the climate zones of north-eastern NSW, NatHERS zones 9 (Lismore), 10 (Byron Bay) and 11 (Coffs Harbour), along with apartment buildings of up to five storeys statewide, because the ACIL Allen cost-benefit modelling found the bill savings from the higher standard would not cover the extra build cost in our mild climate. Every Northern Rivers council area (Tweed, Byron, Ballina, Lismore and Richmond Valley) sits in zone 9 or 10, so a new home here keeps the pre-2023 thermal standard and the pre-2023 energy target, and dark roofs remain available under the DIY method. The department promised a fresh cost-benefit analysis before the next review; as at October 2026 the exception still stands, and the BASIX tool applies the right zone from the address. Two practical results: a Northern Rivers certificate is easier to pass than a Sydney one, and a design that does meet 7 stars anyway (orientation, eaves, insulation, breezes) needs a smaller battery to stay comfortable, which is money better spent.

How solar, hot water and air conditioning score

The planning department’s own list of ways to meet the energy target is short: orientation and shading, an electric heat pump or solar hot water system, photovoltaic panels, and a 3-star or better reverse-cycle air conditioner. In practice:

Related: the hot water heat pump guide and sizing calculator and getting off gas: induction circuits and the all-electric home.

The all-electric new build

Most of the Northern Rivers has never had mains gas (only Tweed Heads and Banora Point are on the Allgas network), so a “gas” new build here means LPG bottles, a rental fee and deliveries for one or two appliances. Nearly every new home we design now is all-electric: a heat pump for hot water on a daytime timer, an induction cooktop on a 32 A circuit, reverse-cycle for the few cold weeks and the hot ones, an EV charger circuit to the garage whether or not the car has arrived, and solar with a battery to run it all. It removes the second account, it scores well in BASIX because the heat pump replaces the gas line, and in a blackout the battery keeps the cooking and the hot water going, which a gas bottle cannot do for the rest of the house.

The load side of that decision, appliance by appliance, is in our getting off gas guide; the car in our EV buyer’s guide for home charging and solar.

Sizing: people, loads, winter, evening

A new build is the one time the loads are a list rather than a bill, so we size from the list and then check it against the family’s habits. Typical daily figures we use: about 3 kWh plus 3.5 kWh per person for the household itself; heat pump hot water 1 kWh plus 0.5 per person; induction cooking 0.4 plus 0.3 per person; ducted reverse-cycle about 8 kWh a day averaged over the year (two to three splits about 4, one split about 2); an EV about 6.5 kWh a day at 250 km a week; a pool pump about 6. Then two rules:

1. Size the solar for winter. Each kW of panels makes about 3.8 kWh on an average Northern Rivers day and about 30 per cent less in June. If the roof cannot fill the battery on a winter day, the battery is the wrong size or the roof is.
2. Size the battery for the evening. About 55 per cent of a working household’s use happens after dark, less once the hot water, pool and EV are timed into the day. The battery carries that evening with margin; GoodWe ESA comes in 8 kWh modules (8 to 40 kWh) and Sigenergy in 9 kWh modules (9 to 45 kWh), and both take another module later.

Most new all-electric homes here land between 8 and 13 kW of solar with a 16 to 27 kWh battery. Background: how big a solar system do I need?, what size battery do I need? and the Northern Rivers home battery buyer’s guide.

Single or three phase: decide before the slab

The supply size is set in the connection application to Essential Energy and the consumer mains are run before the slab, so it is a plan-stage decision that is cheap to get right and expensive to change. Single phase (about 63 A) is normal and carries a typical home, a 10 kW hybrid inverter, a battery and a 7 kW EV charger. Three phase earns its keep when ducted reverse-cycle, an EV charger and a large battery all land on the same house, when a workshop or a pool heat pump is planned, when the block is long, or when a 22 kW charger or a three-phase battery system is wanted. The in-between option is load management: an EV charger that backs off when the house is busy, and the pool and hot water on daytime timers.

We give builders a one-page load estimate for the application at no cost. More in single phase vs three phase for solar and batteries.

Solar and battery ready: what the builder pre-installs

“Solar ready” means different things to different builders; some bundle the basics, others price every item, so have it defined in the contract. Our list, in the order it is cheapest to do:

1. Roof plan: a north to west plane at 10 to 30 degrees kept clear of flues, vents, skylights and the air conditioning condenser; shading from a second storey or trees raised while the plan can still move; the frame rated for the panel weight.
2. Conduit from the roof space to the switchboard (and to the battery position), capped at both ends.
3. Switchboard: spare ways, RCBO protection on every circuit as the Wiring Rules require, room for the battery breakers and a backup changeover, and a meter board the retailer’s smart meter installer will accept.
4. Battery wall: the location rules in AS/NZS 5139 and the makers’ manuals: not in a habitable room, not within 600 mm of an exit or an openable window into a habitable room, protected from vehicles, shaded, on a non-combustible or protected wall, and 500 m from the surf for the brands that require it. See where can a home battery be installed? and solar and batteries near the coast.
5. Dedicated circuits: 32 A to the cooktop, a heat pump circuit with a timer-ready point on the normal supply (not controlled load 1), a 32 A single-phase or three-phase run to the garage for the EV charger, and the pool pump on a timer circuit.
6. Data: an Ethernet point or strong Wi-Fi at the inverter and battery position; the monitoring, the backup app and any VPP depend on it.
7. Supply: single or three phase decided and applied for with the loads above in mind.

Timing with the builder, the certifier and the rebates

1. Plan stage: send us the drawings; we return a roof layout, a solar and battery size, the circuits list and the phase recommendation at no cost, and the designer puts the PV and the heat pump into the BASIX energy section.
2. Frame and roof on: the firm quote, once the roof planes, the switchboard position and the battery wall are real; the site visit is where the battery position and the switchboard are confirmed, so nothing is added on the day.
3. Lock-up to fit-off: install after the external walls, the meter and the permanent supply are in; the certifier may want the BASIX PV commitment in place before the occupation certificate, so book it with the builder’s program.
4. Grid connection and handover: we lodge the connection with Essential Energy, the retailer configures the smart meter for exports, and we set up the app and the backup circuits with you.
5. Rebates and finance: the federal Cheaper Home Batteries rebate and the solar STCs are set by the install date (the battery factor steps down for installs from 1 January 2027 and again from 1 July 2027), so a build that slips past New Year steps down with it; we build both into the design. The NSW Home Energy Saver 0% loan (up to $15,000 over up to 10 years, through Brighte, for eligible NSW homeowners with a combined taxable income of $210,000 or less) is for the home you own and live in, so it is applied for after handover; eligibility criteria apply, subject to lender approval, and you pay the same price either way.

Rebate detail: who qualifies and how the rebate is claimed and how the NSW 0% loan works. Tariff and meter changes that come with a new connection: smart meters, controlled load and time-of-use in the Essential Energy area.

Air conditioning is the load that sizes the solar, the battery and often the phase in a new home: see running air conditioning on solar and a battery.

Building a pool with the house? The running your pool on solar guide covers the BASIX commitments, the circuits and the solar a heat pump needs.

Questions we get asked

Do I need a BASIX certificate for a new home in the Northern Rivers?

Yes. Every new house and apartment in NSW needs a BASIX certificate lodged with the development application or complying development certificate, and so do alterations and additions costing $50,000 or more and swimming pools of 40,000 litres or more. The certificate sets commitments for thermal performance, energy (a percentage cut in greenhouse emissions against a fixed benchmark) and water, and the certifier checks them at the occupation certificate. The builder or the designer usually arranges it; the homeowner signs off on the design choices that go into it.

Does the 7-star rule apply in the Northern Rivers?

Not yet. The higher BASIX standards that took effect on 1 October 2023 (7 NatHERS stars for houses and energy targets lifted by 7 to 11 per cent) exclude homes in the climate zones of north-eastern NSW, NatHERS zones 9 (Lismore), 10 (Byron Bay) and 11 (Coffs Harbour), because the government’s cost-benefit modelling found the bill savings did not cover the extra build cost here. Homes in Tweed, Byron, Ballina, Lismore and Richmond Valley therefore keep the pre-2023 thermal and energy standards, and dark roofs stay available under the DIY method. A new cost-benefit analysis is due before the standards are next reviewed, so check the Planning Portal at design time.

Does solar count towards BASIX?

Yes. Rooftop photovoltaic panels are entered in the BASIX energy section and reduce the home’s modelled emissions, and the NSW planning department lists them among the ways to meet the energy target alongside a heat pump or solar hot water system, efficient reverse-cycle air conditioning and good orientation. Solar is often the cheapest way to close the last few points. A home battery does not currently earn BASIX energy credit, because the certificate models emissions, not when the energy is used; the battery’s case is your bills and blackouts, not the certificate.

How big a solar system does a new all-electric home need?

Most new all-electric Northern Rivers homes land between 8 and 13 kW of solar with a 16 to 27 kWh battery, but the answer comes from the loads you choose: people, heat pump hot water, induction, the type of air conditioning, an EV and a pool. Each kW of panels makes about 3.8 kWh on an average day here and about 30 per cent less in winter, so we size for a winter day that still fills the battery. The planner on this page does the arithmetic; the firm design comes from a site visit once the roof plans are final.

Should I ask the builder for three-phase power?

Ask the question early, because it is cheap at the slab stage and expensive later. Three phase is worth it when the house will have ducted reverse-cycle air conditioning plus an EV charger plus a large battery, or a workshop, or a long run from the street; a single-phase supply of about 63 A can run short when those stack up. For a smaller home with splits and a single EV, single phase with a 10 kW hybrid inverter is normal. Essential Energy approves the connection size; your electrician and we can advise before the application goes in.

What should the builder pre-install so the house is solar and battery ready?

Conduit from the roof space to the switchboard, a switchboard with spare ways and room for the battery’s breakers and a backup changeover, a planned battery wall that meets the location rules (not a habitable room, 600 mm from doors and openable windows, protected from cars, shaded), a 32 A circuit to the induction cooktop, a dedicated circuit and timer-ready point for the heat pump, a 32 A circuit (or three-phase) to the garage for an EV charger, data or Wi-Fi at the battery position, and a roof plane facing north to west left clear of flues, vents and skylights. Get “solar ready” defined in the contract; some builders bundle it, others price each item.

When should I get the solar and battery quoted during the build?

Twice. At the plan stage, so the roof layout, the switchboard, the battery wall and the circuits are designed in (we do this from the plans at no cost). Then a firm quote when the roof is on and the switchboard is fitted, with the install booked for after the external walls and the meter are done and before the occupation certificate if the certifier wants to see the BASIX PV commitment in place. The federal rebate and the STCs are set by the install date, so a build that runs over New Year steps down.

Can I use the NSW 0% loan or the battery rebate on a new build?

The federal Cheaper Home Batteries rebate and the solar STCs apply to a new build exactly as to an existing home: taken off the price at the point of sale, set by the install date (the battery factor steps down for installs from 1 January 2027 and again from 1 July 2027). The NSW Home Energy Saver 0% loan of up to $15,000 over up to 10 years, through Brighte, is for eligible NSW homeowners with a combined taxable income of $210,000 or less, for the home they own and live in, so it is applied for after handover rather than through the builder; eligibility criteria apply, subject to lender approval, and you pay the same price with us either way.

Should a new build in the Northern Rivers have gas at all?

Most of the region has no mains gas (only Tweed Heads and Banora Point are on the Allgas network), so “gas” means LPG bottles with rental and delivery. An all-electric new build with a heat pump, induction and reverse-cycle, run on solar with a battery, avoids the second account altogether and is what most of our new-build customers now choose. It also removes the gas appliances from the BASIX energy modelling in favour of the heat pump, which scores well. Our getting-off-gas guide covers the circuits each appliance needs.

Sources

NSW Planning Portal “BASIX standards” (updated 10 March 2025) and “Climate zones” pages; NSW Department of Planning and Environment “Residential building sustainability: BASIX FAQ” (September 2023: scope, the 1 October 2023 increases, the north-eastern NSW climate zone exclusion, ways to meet the energy target); sample BASIX certificates on the Planning Portal (2024-25); Clean Energy Regulator Cheaper Home Batteries Program and solar battery pages (read 24 October 2026); Australian Government energy.gov.au; NSW Climate and Energy Action Home Energy Saver page; AS/NZS 3000, AS/NZS 4777 and AS/NZS 5139 as applied by licensed electricians; Essential Energy connection process; industry practice notes on solar-ready provisions (Energy Matters, Cleantech Controls, builder pages). Load figures from our own calculators and guides. Full list in our research note. Checked October 2026.

More from Sun Connect Solar

• All our free solar and battery calculators
• How big a solar system do I need?
• Single phase vs three phase for solar and batteries
• Hot water heat pump buyer’s guide and sizing calculator
• Getting off gas and the induction cooktop switchboard checker
• Northern Rivers home battery buyer’s guide
• Residential solar in the Northern Rivers