Give every supplier the same household brief
Prepare one description of the property, current solar equipment, electricity use and planned changes. State the main objective and the functions that are essential. Send the same information when seeking each proposal. If one supplier quotes for a future EV and another does not know it exists, their recommendations answer different questions even before price is considered.
Include representative bills and interval data where available, while removing information unnecessary for quoting. Describe the roof, known shading, any roof work planned and possible equipment locations. For an existing system, supply model details and known faults. A Pakenham address identifies the property area but does not explain the particular building, electrical installation or household schedule.
Set out practical constraints honestly. These might include limited side access, a finished garage wall, work-from-home hours or an installation sequence tied to renovations. Ask which items can be resolved remotely and which need a site assessment. A quote can be useful while some facts remain provisional, provided the unresolved items are clearly identified and a process exists to settle them.
Compare a system schedule, not a brand list
Build a simple comparison with one row for each major component. Record the exact panel, inverter, battery and control model where relevant, together with quantities and the intended arrangement. A brand may sell several products with different capabilities. Without model details, the homeowner cannot reliably compare compatibility, dimensions, monitoring or the functions that matter to the brief.
Ask for the roof layout and equipment positions to accompany the schedule. Two packages with the same panel capacity can use different orientations and shaded areas. Two batteries described by the same energy capacity can have different operating arrangements. The useful question is how the proposed combination meets the household's needs, not which brochure has the largest headline number.
Record allowed substitutions and the approval process. If stock changes, ask for a revised schedule before equipment is installed. The substitution should be assessed against fit, electrical design, compatibility and required functions. A statement that the alternative is equivalent needs an explanation tied to your brief. Keep the final accepted version so it can be compared with the installation at handover.
| Compare this | Evidence to request | Why it matters |
|---|---|---|
| Equipment | Exact model and quantity | A brand alone does not define the system |
| Roof layout | Drawing and shade assumptions | Panel count does not establish usable output |
| Site work | Included work and resolved exclusions | Package totals may cover different scopes |
| Functions | Backup, monitoring and controls | Marketing labels may conceal important limits |
| Handover | Documents, demonstration and account access | The owner needs to operate and support the system |
Read the performance estimate as a set of assumptions
Ask which consumption data the estimate uses and whether it reflects current household routines. Note any allowance for future appliances. A forecast based on a generic home is less specific than one using your records, but either should explain its assumptions. Do not treat precise-looking decimal places as evidence that the inputs are accurate.
Check the assumed generation, direct household use, export and battery operation separately. Ask how shading and seasonal variation were handled. If the estimate includes a battery, request an explanation of reserve settings, charging source and any operating arrangement that affects the result. These questions expose the design logic without asking the homeowner to recreate a technical model.
Use the same electricity-rate assumptions when comparing proposals. A favourable tariff in one estimate can make an otherwise similar design appear substantially better. Keep fixed charges, imported energy and export credits distinguishable. Ask what changes if household use is lower or if rates change. A useful estimate explains sensitivity; it does not present one future bill as a guaranteed result.
Turn exclusions into decisions before comparing totals
Read every line described as excluded, provisional, subject to inspection or by others. Some exclusions are reasonable, but they still affect the complete project. Ask whether the item is optional, a known required extra or a condition that cannot yet be assessed. Those categories should not be merged into a vague allowance that prevents a like-for-like comparison.
Common scope questions include roof repairs, access arrangements, switchboard work, cable routes, equipment relocation and making good surfaces. Ask who coordinates each item and whether the final installation depends on it being completed first. A cheaper equipment package may simply leave more work outside the quoted scope. Conversely, a larger scope may include work the household does not need.
Keep changes traceable. If a site visit resolves an uncertainty, request an updated quote rather than a verbal assurance that the team will handle it. Mark the revision date and discard superseded copies from the active comparison. This prevents an old exclusion from reappearing during installation because different people are working from different versions of the agreement.
Write important functions as observable outcomes
If backup matters, request a description of the circuits supplied, operating limits and behaviour when stored energy is low. If the goal is reduced evening imports, ask how monitoring will show that result. If an EV charger is included, explain when the car is home and its departure requirements. A product label does not settle these operating questions.
For monitoring, ask who owns the account and what data it displays. Generation-only monitoring differs from a system that also measures household consumption and grid exchange. Confirm any ongoing service or subscription requirements for the features relied upon in the proposal. The homeowner should understand which functions remain available if an optional service is not continued.
For future expansion, replace general readiness language with specific conditions. Ask which equipment can be retained, what additional hardware might be required and what compatibility or connection checks would still apply. An expansion path can be valuable even when not guaranteed forever. The key is knowing what has actually been allowed for in the current installation.
Compare support responsibility as carefully as equipment
A list of warranty periods does not explain the experience of getting a fault investigated. Ask who receives the first report, who decides whether a site visit is needed and which party coordinates equipment support. With a retrofit, identify responsibility for the boundary between retained and new equipment. The homeowner should not have to diagnose that boundary before anyone accepts the enquiry.
Read the actual product and workmanship documents supplied with the proposal. Ask how the stated terms address labour, access, transport and replacement where those matters are relevant. Avoid assuming that every cost is included because a headline period is long. Equally, do not infer that a particular cost is excluded without reading the applicable document. Record unresolved questions rather than filling gaps with guesses.
Check the supplier's identity and relevant credentials through the appropriate current records before proceeding. Do not rely on a badge copied into a brochure or an old accreditation label as the whole check. Ask who performs the work and who issues the applicable installation records. This guide does not certify any business; the comparison should retain the evidence used for the actual contractor selected.
A proposal comparison that changes the decision
Hypothetical example: a Pakenham family receives two similarly sized solar-and-battery proposals. The first includes a detailed roof plan but leaves battery placement provisional. The second confirms placement but describes monitoring only as an app. The family initially prefers the first package, then realises neither proposal yet answers the complete brief.
It sends targeted clarification requests. The first supplier is asked to assess the preferred wall and include the resulting site work. The second is asked what monitoring measures and who receives account access. Both are asked to use the same consumption record and backup circuit requirement. The revised proposals can now be compared on a consistent basis, rather than on a mixture of confirmed and assumed functions.
The family may still select either supplier, but the reason becomes explainable. It might value a clearer layout, a better-supported operating arrangement or fewer unresolved site conditions. If a supplier cannot answer a material question, the uncertainty remains a reason to pause that proposal. It should not be silently scored as equivalent to a documented answer.
Plan handover while there is still time to specify it
Ask what documents, drawings, manuals and installation records will be delivered. Include the final equipment schedule and relevant connection information. Request homeowner access to the monitoring account and a demonstration of the ordinary functions included in the scope. If backup was specified, agree how the installer will demonstrate it safely and record the result.
Have the person who will use the app attend handover where practical. Ask them to explain the main measurements back in their own words so misunderstandings can be corrected. Save support contacts and the first useful operating record. A system can be physically complete while the household still lacks the information needed to understand an alert or question a bill.
After handover, compare the installed equipment and arrangement with the final accepted proposal. Raise differences using the drawings and model list rather than memory. Keep unresolved items in a written list with the responsible party and next action. The downloadable brief below helps identify the most useful clarification questions before committing, when they are easiest to resolve.
Create a small acceptance record with three columns: promised item, evidence received and unresolved question. For equipment, the evidence may be the model label and final schedule. For monitoring, it may be access to the homeowner account and an explained daily report. For a site-work item, it may be the agreed finished cable route or completed reinstatement. This keeps acceptance focused on the actual proposal. It also prevents a general statement that the system is running from being mistaken for completion of every promised feature.
Separate an information gap from a physical defect when raising an issue. Missing documentation may need an administrative response, while a discrepancy in installed equipment needs the responsible supplier to investigate. Describe the observation without guessing the cause. Attach the relevant page of the accepted proposal and a clear photograph or screenshot where useful. Ask for the next action and the person responsible, then keep the reply with the project records. A precise request is easier to resolve than a broad complaint that combines unrelated matters.
When several household members take part in the purchase, nominate one person to maintain the current document set. Others can still ask questions, but model changes, location decisions and exclusions should be reflected in the same accepted revision. This avoids a telephone agreement with one person conflicting with an older email held by another. The final comparison becomes a practical project record rather than a spreadsheet that stops being useful once a supplier is selected.