Comparing solar panel companies means comparing the systems and contracts they are offering, not just the headline price. A cheaper proposal may use a different system size, assume different electricity rates, leave out electrical work, or rely on a less suitable financing arrangement. Ask each company to price the same basic project, then compare equipment, estimated production, installation responsibilities, warranties, payment terms, and the assumptions behind projected savings. The best fit is the proposal that works for your roof, electricity use, budget, and plans for the home, with responsibilities clearly set out in writing.
Before reviewing quotes, give each company the same information: recent electricity bills, your plans for changes in household electricity use, and any known roof or electrical issues. If you expect to add an electric vehicle, change heating equipment, or expand the home, mention it. A proposal based on today’s usage may not suit a home whose electricity needs are likely to change.
Ask for an itemised proposal that separates the system design from the price and financing. A quote that lists only a monthly payment or a total price is difficult to assess. Use the table below to identify the main points that should match across proposals.
| Proposal item | What to compare | Question to ask |
|---|---|---|
| System design | System capacity, panel layout, estimated annual production, and any battery | What roof, shading, and electricity-use assumptions shaped this design? |
| Equipment | Panel and inverter models, monitoring, and battery specifications if included | Are these exact models named in the contract, and can they be substituted? |
| Installation scope | Labour, electrical work, roof work, permits, inspections, and utility coordination | Which tasks are included, and what could be an additional charge? |
| Price and payment | Cash price, financed cost, fees, payment schedule, and applicable incentives | Does the quoted amount depend on an incentive or a separate financing offer? |
| Warranties and service | Equipment coverage, installation workmanship, roof penetrations, and service process | Who handles a problem, and what remedy is promised in writing? |
| Production and savings | Estimated electricity generation, utility-rate assumptions, and bill-credit treatment | Which parts of the estimate are assumptions rather than guarantees? |
Do not treat a higher system capacity as automatically better. Compare expected electricity production and how much of your household use it may cover, while accounting for the utility’s rules for exporting excess power. Those rules vary by location and can affect the value of a system’s output.
Ask each company to explain how it arrived at the proposed system size. The design should take account of your electricity use, usable roof space, shading, roof orientation and condition, and any likely changes in demand. A proposal that simply aims to cover a particular share of annual use may not reflect when your home uses power or how your utility values electricity sent to the grid.
Compare the estimated annual production in kilowatt-hours, not only the panels’ combined capacity. A company should be able to show the proposed panel layout and explain the inputs behind its production estimate. Ask whether the estimate accounts for shading, equipment and wiring losses, and other site conditions. If proposals differ substantially, ask each company to identify the reason rather than assuming the higher estimate is more accurate.
Roof work deserves attention before you sign. Ask whether the installer has assessed the roof’s condition and whether repairs or replacement are recommended before panels go on. Clarify who pays if hidden damage is found, whether removing and reinstalling panels for later roof work is included, and how the installation affects coverage for roof penetrations. Get any commitments about roof repairs in the contract.
If you are considering a battery, ask what it is intended to do: provide backup power, store solar energy for later use, or both. The answer depends on the system design and the equipment included. Confirm which circuits or loads the proposed setup can support, how it operates during an outage, and whether battery installation, controls, and any required electrical work are included in the quoted scope. Do not assume that adding a battery guarantees whole-home backup.
Proposals should identify the panel and inverter models, and any battery model, rather than describing equipment only in general terms. Compare the specifications that matter to the design and ask whether the quoted models can be changed before installation. If a substitution is allowed, find out whether you must approve it and whether the replacement must meet stated performance or warranty requirements.
| Component | Details to check | Trade-off to understand |
|---|---|---|
| Solar panels | Model, rated output, product coverage, and performance warranty | Panel ratings alone do not predict the production of a particular roof layout. |
| Inverter system | Model, system type, monitoring, warranty, and replacement process | Different designs can suit different roofs; ask why the proposed type was selected. |
| Battery | Model, usable capacity, operating mode, warranty, and backup configuration | Backup capability depends on system design and the loads connected, not just battery presence. |
| Monitoring | What production and system-status information you can access | Monitoring can help identify issues, but it does not replace service or repair commitments. |
Warranty documents can be easy to misread because equipment coverage and installation coverage are different. A manufacturer’s warranty applies to the equipment under its stated terms; the installer’s workmanship warranty concerns the installation. Ask who submits a manufacturer claim, who pays for labour or removal and reinstallation if needed, and how you can reach the responsible party if the installer is no longer available. Check exclusions, transfer terms, and the process for making a claim rather than comparing warranty length alone.
The company that sells a system may not be the company that performs every part of the work. Ask who will design the system, complete the electrical work, manage permits and inspections, and coordinate with the utility. If subcontractors will be involved, ask which parts they handle and who remains responsible for the finished project and any service request.
Confirm that the people performing the work hold the licences and insurance required for the work in your area. Ask the company to explain how it handles issues after installation, including the best contact for a fault, a monitoring alert, or a warranty claim. A sales contact may not be the right person to resolve a service problem, so get the service process in writing.
References can help you understand how a company manages communication and follow-up. Ask for examples of residential projects with features similar to yours, such as a comparable roof layout or a battery installation. References are not a guarantee of your own experience, but a conversation may reveal whether the company explains delays, answers questions, and stays involved after the installation.
A complete contract should describe the system being installed, the work included, the payment terms, and what happens if the project changes. Check that the equipment models and system design match the proposal you accepted. Make sure any verbal promise about a particular panel, roof repair, production estimate, or service response appears in the written documents.
Look for clear responsibility for permits, inspections, utility interconnection, and any required electrical or roof work. Ask whether panel removal for roof repairs, trenching, service-panel changes, or other site work is included or excluded. If an inspection identifies extra work, find out how the company will explain the cost and get your approval before proceeding.
Also review the project schedule and its dependencies. Installation may rely on approvals, inspections, equipment availability, or utility steps that the installer cannot control. Ask what milestones trigger payments, what happens if the schedule changes, and who will update you. Read the contract’s cancellation, change-order, dispute, and system-ownership terms; applicable consumer rules differ by location, so do not assume a sales explanation replaces the written terms.
First compare the cash price, if one is provided, before comparing monthly payments. A low advertised payment can depend on a particular loan structure, fees, a payment schedule, or assumptions about incentives. Ask for the full financing documents and compare the total amount payable, interest and fees, payment timing, and any conditions that could change the amount due.
| Payment option | What to examine | Points to verify before signing |
|---|---|---|
| Cash purchase | Total project price and payment milestones | What is included in the price, and how are added costs approved? |
| Solar loan | Interest, fees, term, payment schedule, and total repayment | Does the payment change, and is any payment reduction based on a separate action? |
| Lease | Payment structure, term, service obligations, and transfer provisions | Who owns the equipment, and what happens if you sell the home or end the agreement? |
| Power purchase agreement | How the energy charge is calculated and whether it can change | How are excess production, transfers, and early termination handled? |
Ownership affects who may qualify for available incentives and who is responsible for equipment obligations. Incentives and tax treatment depend on location, eligibility, and the arrangement you choose. Ask the company to identify which incentives it has included in its calculation and whether you must qualify or take a separate action to receive them. Verify eligibility independently before treating an incentive as a guaranteed reduction in your cost.
Projected savings are estimates, not promises unless the contract explicitly provides a defined guarantee and remedy. Ask for the assumptions behind the estimate: expected system production, electricity prices, utility charges, export credits, system degradation, and any battery operation. Compare proposals using consistent assumptions. If one company assumes faster electricity-price increases or more favourable bill credits than another, its savings figure may look better without the system itself being better.
Review a bill or savings estimate that distinguishes charges the solar system may reduce from charges that could remain. The effect depends on your utility’s billing rules, your consumption pattern, and system output. Ask the company to show how it calculated the estimate and what happens if actual production is below its forecast. Do not compare a loan payment directly with an estimated bill reduction without considering the full loan cost and the parts of the bill that may remain.
Be cautious if a company pressures you to sign before you can review the documents, will not identify the equipment, or presents estimated savings as certain without explaining the assumptions. A credible proposal should make its scope and uncertainties understandable, even when it cannot predict every utility or site outcome.
Not without checking what the quote includes. Compare the system design, equipment, installation scope, financing, warranties, and production assumptions first. A lower price can still be a good offer, but only if the proposals cover comparable work and the contract makes responsibilities clear.
There is no fixed number that suits every project. The useful goal is to obtain enough independent proposals to see whether system size, production estimates, scope, and financing assumptions are consistent or whether differences need explaining.
Production and savings estimates depend on factors such as weather, system performance, household use, and utility billing rules. Treat a savings figure as a projection unless the written contract defines a guarantee, its conditions, and the remedy if it is not met.
A panel warranty comes from the equipment manufacturer and covers the product under its stated terms. An installation or workmanship warranty comes from the installer and concerns the work performed. Ask who handles claims and whether labour, removal, or reinstallation is covered.
Review how the agreement treats a home sale, including transfer requirements, buyer approval, fees, or any option to pay off or end the arrangement. These terms vary by contract and financing type, so ask the company to point to the relevant clauses before signing.
Before choosing among solar panel companies, make sure you can explain what system you are buying, what the installer is responsible for, how the project is financed, and which assumptions support the savings estimate. If a proposal leaves those points unclear, ask for a revised written version before signing.
