Solar energy companies can quote very different prices for systems that appear similar on paper. A lower quote may exclude roof work, grid-connection tasks, monitoring or battery-ready equipment, while an oversized system can cost more than your household needs. Compare complete proposals, not panel totals: check how each company assessed your roof and electricity use, what equipment it will install, who will do the work, how savings were estimated, and what support follows commissioning. In New Zealand, also ask how the provider will manage the connection process with your local electricity distributor. The right choice is the proposal you can understand and verify, not simply the cheapest one.
Before comparing solar energy companies, make sure each is quoting for the same basic outcome. One proposal might include a site assessment and a complete grid-connected installation; another may be based on limited information or leave important work as an extra. Ask for an itemised scope so you can see what is included, excluded and conditional.
| Proposal area | What a useful quote explains | Question to ask |
|---|---|---|
| System design | Proposed system size, panel layout and the assumptions behind the design | How did you account for my roof, shading and electricity use? |
| Equipment | Panel, inverter and battery models, if applicable | Can I see the model numbers and the relevant product warranties? |
| Installation | Included labour, mounting, electrical work, access needs and stated exclusions | What could trigger an additional charge? |
| Grid connection | Who submits the application and what connection-related tasks are included | Will you manage the application with my local electricity distributor? |
| Financial estimate | Expected generation, household use, exported electricity and stated assumptions | Which electricity prices and usage patterns did you use in the estimate? |
| Aftercare | Monitoring, handover documents, warranty contact and fault-response process | Who do I contact if the system stops reporting or producing as expected? |
A quote that leaves these points unclear is difficult to compare, even if its headline price is attractive. Ask each provider to revise its proposal or explain the gaps in writing before you choose.
A suitable design starts with your roof and your household’s electricity use, not a standard package selected from a brochure. The company should ask for recent electricity bills or other consumption information and discuss when your household uses power. Daytime use can affect how much solar electricity you use directly; evening-heavy use may make storage worth considering, but a battery is not automatically the right financial choice.
Ask the provider to show the proposed panel locations on a roof plan. The layout should take account of roof orientation, pitch, shading, usable space and any visible obstructions. If the salesperson has not inspected the roof or used reliable site information, ask how the design will be confirmed before installation. Also establish whether roof repairs, structural concerns or changes to the layout could alter the price.
System size should be explained in relation to your likely use, not presented as “the biggest system that fits.” A larger array may generate more electricity, but its value depends on how much you consume, how much can be exported and the terms available from your electricity retailer. Ask the company to explain why it selected that size and what a smaller or larger option would change.
Projected savings are estimates, not guaranteed bill reductions. They depend on system generation, your future electricity use, how much solar power you consume at home, electricity prices, export credit arrangements and system performance over time. Ask for the assumptions behind the calculation rather than relying on a single payback figure.
Separate estimated solar generation from estimated financial benefit. The first is an output forecast; the second depends on how the household uses that output and what it would otherwise pay for electricity. Find out whether the estimate assumes your current routine will remain unchanged, and whether it includes the cost of financing, maintenance or a future battery. If two companies forecast markedly different savings, ask them to reconcile their assumptions before comparing the results.
“Premium panels” or “a high-quality inverter” are not enough detail to make an informed choice. Your proposal should identify the equipment models so you can compare like with like and check which warranties apply. Panels, inverters and batteries have separate product terms, and a product warranty is not the same as a promise to cover labour, removal or a return visit.
Ask who handles a warranty claim and what happens if the original installer is no longer available. Clarify whether the company or the equipment manufacturer is your first point of contact, and whether any costs associated with diagnosing or replacing a faulty component are included. Get the warranty documents and any relevant limitations before signing.
Inverters convert the electricity produced by the panels for use in the home or connection to the grid. The design may use a central inverter, microinverters or another configuration; each has different implications for monitoring, layout and future servicing. Ask why the proposed type suits your roof and array. If you may add a battery later, confirm which equipment would be required and whether today’s design supports that plan. “Battery-ready” can mean different things, so request a clear description rather than assuming it includes the battery or all the necessary hardware.
Ask whether the company uses its own installation team or subcontractors, and who is responsible for the project from site confirmation through commissioning. The answer should identify a contact for scheduling, site questions and problems after installation. If several businesses are involved, find out which one is contractually responsible for the finished work.
For a grid-connected system, clarify who submits the connection application to your local electricity distributor and whether the proposal includes that work. Distributor requirements and export arrangements can vary by location, so do not assume that a system can be connected or export electricity on identical terms everywhere. Ask what approvals or steps must be completed before the system can operate and who will keep you informed.
Confirm how the installation will be checked and what you will receive at handover. Useful documents may include the final system layout, equipment details, operating instructions, warranty information and records of commissioning or connection. The company should explain how to view system performance and whom to contact if the monitoring platform shows an issue. Do not treat a monitoring app as a substitute for a clear support process.
Review the total price and the scope line by line. Look for exclusions such as roof repairs, electrical upgrades, difficult access, additional cabling, monitoring equipment or work required after an on-site assessment. An exclusion does not necessarily make a quote poor, but you need to know about it before comparing totals. Ask how changes will be priced and approved if unexpected work is identified.
If financing is offered, compare the total amount you would pay over the agreement, not only the regular payment. Check fees, interest, payment term, any deposit, early-repayment conditions and who owns the equipment during the agreement. A finance plan can make the initial cost easier to manage while increasing the total cost, so compare it with the cash price and any alternative finance you are considering.
Do not base your decision on an incentive or rebate mentioned in a sales conversation alone. Ask the provider to identify the programme, confirm whether you appear eligible and show how the estimate changes if the support is unavailable. Check the terms independently before relying on an incentive in your budget.
Look for specific, consistent answers rather than a polished sales presentation. A provider should be able to explain trade-offs, including why it recommends a particular system size or inverter, and should give you time to review the contract. Ask for references or examples of comparable residential work if you want additional reassurance, while recognising that another homeowner’s experience cannot guarantee the same outcome at your property.
This process is more useful than ranking providers by a single feature. A company with a clear design and support plan may suit a homeowner who values predictable project management; a lower-cost proposal may be suitable if its scope, equipment and service arrangements are equally clear. The comparison should turn on what each provider will actually deliver at your home.
Pause before accepting a quote if it promises a specific saving without explaining the assumptions, recommends a battery without asking about your usage, or avoids identifying the equipment models. Be cautious if the price is conditional on decisions you are pressured to make immediately, or if verbal promises do not appear in the written proposal.
Other reasons to ask for clarification include a roof layout that does not reflect your home, unclear responsibility for grid connection, vague warranty language, and a contract that leaves significant work open-ended. These issues do not prove that a provider is unsuitable, but they need resolution before you commit. If the company cannot give a clear written answer, compare another proposal.
There is no fixed number, but comparing more than one proposal helps reveal differences in design, scope and assumptions. Make the comparison useful by giving providers the same household information and asking for the same key details.
Not necessarily. It may be good value if it covers the same work, uses equipment that suits your needs and provides clear installation and support terms. First check for exclusions, different system sizes or assumptions that make the headline prices unlike-for-like.
That depends on your electricity-use pattern, the value of using stored power, your budget and the battery’s full installed cost. Ask for separate estimates with and without storage, and have the company explain the assumptions rather than presenting a battery as essential.
Be wary of treating a savings projection as a guaranteed outcome. Generation and bill savings depend on factors such as weather, household use, electricity prices and export arrangements, some of which can change. Ask exactly what a guarantee covers and how it would be measured.
Ask for the final system and equipment details, operating and monitoring instructions, warranty documents, and records relevant to commissioning and grid connection. You should also know who to contact for faults, warranty claims and questions about system performance.
When comparing solar energy companies, judge the whole project: design, equipment, installation, connection, financing and aftercare. Request written answers to any unresolved questions, then compare the final proposals on the same assumptions. A well-explained system that fits your roof and electricity use is a more dependable basis for a long-term decision than a low panel quote alone.
