The top solar companies are the ones that can explain why a particular system suits your roof, electricity use and budget—not simply those offering the largest savings estimate. For New Zealand homeowners, a useful comparison covers the design, equipment, installation team, grid connection process, contract and after-sales support. Ask each company to work from the same household information and spell out how its estimate treats electricity you use, export to the grid and buy from your retailer. That makes quotes easier to compare and helps expose assumptions that could affect the system’s value over time.
Start with the proposal, not a company’s headline claims. A credible provider should be able to show how it assessed your roof and electricity needs, explain its equipment choices, and identify what is and is not included in the installation price. It should also make clear who is responsible for electrical work, network connection arrangements and support if something goes wrong.
Use the same questions for every company. The table below gives you a practical framework for comparing proposals without relying on brand recognition or a single payback estimate.
| What to compare | A useful proposal explains | Check before accepting |
|---|---|---|
| System design | How roof conditions and household electricity use shape the system size and layout. | Whether shading, roof condition and future changes to your electricity use were considered. |
| Equipment | The panel, inverter and, if included, battery models and their roles. | Warranty terms, compatibility and what happens if a component needs replacement. |
| Installation | Who will do the work, what it includes and how grid connection will be handled. | Electrical credentials, switchboard work, exclusions, commissioning and handover documents. |
| Financial estimate | How the company estimates electricity savings and any export credits. | Retailer assumptions, financing costs, fees and whether savings are guaranteed or projected. |
| Support | Who to contact for installation issues, monitoring questions and warranty claims. | Which warranties cover equipment and which cover workmanship. |
A table can help you organise the comparison, but it cannot determine which system is right without your household details. A lower quote may exclude work another provider has included, while a larger system may produce more electricity than your household can use economically. Ask each company to explain the trade-offs in its own design.
A good design begins with the roof and your electricity use. Ask the company how it assessed the roof’s orientation, pitch, shading, usable area and condition. Trees, nearby structures, roof features and the condition of the roof can affect panel placement or installation planning. If the proposal was prepared without a site assessment, ask which details are still estimates and whether the price or design could change after inspection.
The system size should be connected to your actual consumption, not just the amount of roof space available. Share recent electricity bills and, if your retailer can provide it, interval usage data. Your pattern of use matters: a household that consumes more electricity while the panels are generating may use more solar power directly than one that mainly uses electricity in the evening. A company should explain how it has accounted for that difference.
Ask what the design assumes about future demand. An electric vehicle, heat pump, home extension or other planned change could affect consumption, but it does not automatically mean that a larger system is worthwhile. Have the company model the proposed system against a realistic usage scenario and explain the extra cost and likely benefit of any expansion.
The inverter converts the panels’ output into electricity your home can use. Compare the proposed inverter type and model, how it suits the panel layout, and what monitoring is included. If a company recommends a particular configuration, ask it to explain the reason in terms of your roof and system rather than relying on a brand name alone.
A battery is a separate decision, not an automatic addition to a solar system. It may be worth considering if you expect to use stored electricity later in the day, but its value depends on your usage, electricity plan, battery cost and system design. Ask for estimates both with and without storage so you can compare the difference. If you want backup power during an outage, confirm that the proposed battery and wiring provide that function; a battery connected for ordinary energy use does not necessarily keep the home powered when the grid is down.
Request the exact model names for the panels, inverter and battery, if applicable. “Premium panels” or “high-quality inverter” is not enough information to assess a quote. Compare equipment on the basis of suitability, documented warranty terms, compatibility and the company’s ability to explain how the components work together.
Separate equipment warranties from workmanship cover. A manufacturer’s warranty applies to its product under the stated terms, while an installer’s workmanship cover relates to the installation. Ask who handles a claim, what evidence you need to keep, and whether the company expects you to contact the manufacturer directly. Get the answers in writing rather than relying on a general assurance that the system is “fully covered.”
Also ask how the system will be monitored and what happens if monitoring shows a fault. Clarify whether monitoring is included, who reviews alerts and whether a service visit or replacement part could involve extra costs. A clear support process can matter long after installation, especially if the original sales contact is no longer your point of contact.
The proposal should identify the work included from the roof installation through to commissioning and handover. Ask whether the quoted price includes any necessary switchboard or electrical work, system monitoring setup, testing and documentation. If extra work may be required, ask what could trigger a variation and how you will approve its cost before the work proceeds.
For a New Zealand installation, ask which registered electrical worker will be responsible for electrical work and how to verify their current practising licence with the Electrical Workers Registration Board (EWRB). Also ask the company to explain the connection process for your local lines company, including who submits any required application and when the system can be connected. Responsibilities and processes can vary, so do not assume these steps are included unless the proposal says so.
Find out who will actually install the system. A company may use its own employees or subcontractors; either arrangement can work, but you should know who is coming to your home and who is accountable for the finished job. Ask about the expected sequence of work, access requirements, how the site will be left, and what documents you will receive after commissioning.
A savings projection is an estimate, not a promise of a fixed bill reduction. Its result depends on how much electricity the system generates, how much you use directly, how much you export, your retailer’s charges and export-credit terms, and how those arrangements change over time. Ask each company to show the assumptions behind its calculation, rather than presenting a single payback period without explanation.
In New Zealand, compare the proposal’s assumed electricity purchase rate and export credit with the terms available from your own retailer. Retail plans and export arrangements can differ, so a projection based on one set of assumptions may not match your account. Ask the company to show how the estimate changes if you use less power during solar-generating hours or receive a different credit for exported electricity.
Check whether the estimate includes the full installed cost and any financing charges, and whether it accounts for optional equipment or work that is not in the base quote. If a battery is proposed, compare its cost and estimated effect separately. A confident answer should explain uncertainty and show what drives the result; it should not depend on a savings figure that cannot be traced back to clear assumptions.
Compare total costs on the same basis. Check whether each quote includes the same system capacity, equipment, installation work, monitoring and connection tasks. Ask for a written breakdown of exclusions, optional upgrades and possible additional charges. If one quote is substantially lower, find out whether it reflects a different design or whether some work has simply been left out.
If financing is offered, compare the complete payment obligation rather than only the initial payment or advertised instalment. Ask about fees, interest, payment duration, early repayment conditions and who owns the equipment during and after the agreement. If a company proposes a lease or another arrangement in which you do not own the system outright, clarify how the agreement may affect a home sale, maintenance responsibility and access to equipment warranties.
Pay attention to the contract’s cancellation terms, deposit requirements, installation timing and process for approving changes. Make sure the final design and equipment list are attached to the agreement, or otherwise clearly identified in writing. Do not sign based on a verbal promise that a particular component, service or connection step will be included later.
One concern does not necessarily prove that a company is unsuitable, but unresolved gaps make a quote difficult to evaluate. Ask for written answers and compare the revised proposal with the others before proceeding.
The right choice may not be the lowest quote or the company with the most recognisable equipment. Look for a proposal that fits your home, explains its limitations and makes responsibility clear from design through after-sales support.
No. A low price may reflect a smaller system, different equipment or work excluded from the quote. Compare the complete design and contract scope before deciding whether the price represents good value.
Choose a battery only if its cost and operating role make sense for your household. Ask for a comparison with and without storage, and confirm whether backup power during an outage is actually included if that is one of your aims.
Yes, but first check that the estimates use comparable assumptions about system output, household consumption, exported electricity and retailer terms. If the assumptions differ, ask each company to recalculate or explain the difference so you are not comparing unlike projections.
Identify the separate terms for panels, inverter, battery and installation workmanship. Confirm who receives a claim, what documentation you need and whether any service or replacement costs could fall to you.
The answer depends on how the system was purchased and any financing or lease agreement attached to it. Before signing, ask how ownership, outstanding payments, warranties and transfer arrangements would work if you sold the property.
To choose among top solar companies, compare complete, site-specific proposals rather than headline claims. The strongest option is the one that fits your roof and electricity use, sets out its costs and assumptions clearly, and gives you a practical plan for installation and support.
