The rule: compare the written scope, not the headline price
A lower headline price can describe a different battery size, output, backup arrangement, cable route, switchboard treatment, certificate assumption or variation position. A more expensive quote can have gaps too.
The ACCC recommends comparing like with like and checking the contract, warranty, finance and installation details before you sign.[1] The useful comparison is not “Which quote is cheaper?” It is: “What is actually being supplied, designed, installed, certified and excluded?”
Use the worksheet below with each proposal. Where the quote is silent, write not confirmed and ask for a written answer.
The solar and battery quote-comparison worksheet
Save or print this worksheet: use your browser’s print or save-to-PDF option, then complete the same prompts against each written proposal. The worksheet is a buyer aid—not a technical approval, quote or provider ranking.
1. System identity
Write the exact model information—not only the brand.
- Quote A: solar panels / battery / inverter / controller or Gateway / monitoring / EV equipment:
- Quote B: solar panels / battery / inverter / controller or Gateway / monitoring / EV equipment:
- Ask: Is every model number, capacity and firmware-dependent feature specified in the final proposal?
Why it matters: product families can include different capacities, outputs, warranties and phase arrangements. A brand name alone is not an installation scope.
2. Capacity and power are different
- Quote A usable battery capacity (kWh):
- Quote A continuous and surge output (kW or kVA):
- Quote B usable battery capacity (kWh):
- Quote B continuous and surge output (kW or kVA):
- Ask: Which stated household loads and runtime assumptions were used?
A battery’s kWh describes stored energy; kW or kVA limits how much can run at once. The Australian Government advises that capacity, battery management, household demand and the intended operating mode all affect the real outcome.[2] Do not compare kWh alone.
3. Solar-only, battery storage or actual backup design?
- Quote A blackout scope: no backup / selected circuits / one phase / broader design / not confirmed
- Quote B blackout scope: no backup / selected circuits / one phase / broader design / not confirmed
- Ask: What will operate during an outage, what will not, and what output, phase, transition and operating limits apply?
Grid-connected solar-only systems normally stop during an outage for anti-islanding safety. A battery may provide backup only when the proposed system is designed and configured for it.[2] A phrase such as “backup ready” is not enough—ask for the intended loads and limits in writing.
For a three-phase home, also ask whether the proposal covers one phase, selected circuits or a designed three-phase/broader backup arrangement. See our three-phase home battery guide.
4. Existing solar and inverter treatment
- Quote A existing equipment: stays / replaced / new role / not confirmed
- Quote B existing equipment: stays / replaced / new role / not confirmed
- Ask: What manufacturer compatibility evidence, warranty position, communications/protection changes and AC/DC-coupling architecture apply?
Adding a battery to existing solar is possible on many properties, but compatibility and retained equipment are not automatic. NSW guidance recommends confirming battery/inverter compatibility and notes that switchboard work may be required.[3]
5. STCs and other incentive assumptions
- Quote A pre-STC price:
- Quote A current certificate calculation / pass-through basis:
- Quote B pre-STC price:
- Quote B current certificate calculation / pass-through basis:
- Ask: Which rules, equipment listing, capacity, installation timing, accreditation and contract assumptions support the calculation?
The Clean Energy Regulator’s current battery pathway uses Small-scale Technology Certificates (STCs) subject to conditions for eligible equipment, configuration, capacity, installation and evidence.[4] It is not a fixed cash rebate for every quote. Compare the pre-STC scope first, then the dated calculation and written pass-through terms.
6. Electrical and site work
For each quote, list whether it includes or excludes:
- switchboard, meter, protection and compliance work;
- battery location preparation, clearances, mounting and physical protection;
- cable routes, trenching, roof access, scaffolding or difficult access;
- removal, relocation or modification of existing electrical equipment;
- network connection application, export settings and commissioning; and
- fire, structural, strata, heritage, engineering or distributor requirements where relevant.
A quote can be technically sound and still require site-specific scope. The correct question is whether the variation pathway is visible before you accept, not whether a provider can promise that no variation will ever arise.
7. Connection, export and operating controls
- Quote A distributor / export position:
- Quote B distributor / export position:
- Ask: Which distribution network, connection application, meter/export setting and control requirements apply to this address?
Network approval is separate from a certificate calculation. Connection and export rules depend on the applicable distributor, installation, inverter and approved design. Do not treat an example export figure from another network area as a promise for your property.[4]
8. Warranty and support documents
- Quote A product warranties / workmanship terms / monitoring or support scope:
- Quote B product warranties / workmanship terms / monitoring or support scope:
- Ask: Who is responsible for manufacturer warranty, workmanship, monitoring access, commissioning records and future support?
Compare the actual documents, term, exclusions and claims process—not just a warranty headline. The ACCC’s consumer guidance is a useful prompt to read the contract and warranty terms before committing.[1]
9. EV charging and V2H are separate items
- Quote A EV equipment: AC charger / DC charger / bidirectional equipment / not included
- Quote B EV equipment: AC charger / DC charger / bidirectional equipment / not included
- Ask: Is the exact vehicle, model year, manufacturer support/warranty position, charger, software, phase arrangement and electrical protection confirmed?
A home battery does not automatically make an EV charger bidirectional, and an ordinary EV charger is not automatically a vehicle-to-home system. Treat V2H as a separate, compatibility-checked pathway.[5]
10. Finance is a second decision
- Quote A cash price and finance product are shown separately: yes / no / not confirmed
- Quote B cash price and finance product are shown separately: yes / no / not confirmed
- Ask: What are the lender, rate, fees, repayment, term, total amount repayable, eligibility and approval conditions?
A technical proposal and a credit application answer different questions. Read the current lender disclosure and contract; finance approval does not prove system suitability, future bill savings or incentive eligibility.[1]
How to make a fair final comparison
Once the worksheet is complete, put both proposals into one of three groups:
- Comparable now: equipment, capacity/output, backup scope, electrical/site work, STC assumptions and warranties are stated clearly enough to compare.
- Needs clarification: a material item is missing, ambiguous or described only in marketing language.
- Different pathway: the proposals solve different problems—for example, storage-only versus backed circuits, retained inverter versus replacement, or a staged electrification design versus an immediate package.
Ask the same written question of each provider. That is fairer than trying to force unlike scopes into one price comparison.
A concise message you can send before signing
Please confirm the exact equipment models; usable kWh; continuous/surge kW or kVA; supply phase and intended backed loads; existing-inverter treatment and compatibility evidence; switchboard/meter/cable/site inclusions and exclusions; distributor/export pathway; current STC calculation and pass-through basis; warranties; variation process; and any finance terms. Please identify anything not included in the stated price.
A confident next step
Cable Co’s Energy Assessment can help you organise bills, existing equipment, future loads and resilience priorities before a site review. It does not compare or approve another provider’s quote, determine technical suitability, grant eligibility, finance approval, price, savings, payback, backup or V2H outcome.
Sources and review date
Reviewed on 26 September 2026 using current Australian Government, NSW Government, Clean Energy Regulator and ACCC guidance. Equipment listings, certificate rules, network conditions, finance products, warranties and site conditions can change. Confirm the current position for the exact property and final contract before proceeding.
Sources & references
- ACCC, Solar panel systems and home batteries. ↩
- Australian Government Solar Consumer Guide, Batteries. ↩
- NSW Government, Guide to owning a battery. ↩
- Clean Energy Regulator, Solar batteries. ↩
- Cable Co, Whole-home battery backup and compatible V2H in NSW. ↩