Choosing among solar energy companies is easier when you compare the work each one is proposing, not just its projected savings. Ask every installer to price a system against the same electricity use, roof conditions and financing assumptions. Then check the estimated production, equipment models, installation responsibilities, warranty coverage and total payment obligation. Savings forecasts depend on factors such as utility billing rules, future electricity rates and incentives, so they are not a reliable substitute for a clear proposal. The right contractor is the one whose design fits your home and whose written terms explain what happens if installation, system performance or service falls short.
A proposal is only useful if you can tell what it includes. Request an itemised quote that identifies the system size, estimated annual production, equipment, installation work, payment terms and any exclusions. If one company has not inspected the roof or reviewed your electricity use, ask how it developed its design and whether the price could change after a site assessment.
| What to compare | Ask the company | Why it matters |
|---|---|---|
| System design | What is the system’s capacity, and how was its layout chosen? | Capacity alone does not show how much electricity the system is expected to produce. |
| Production estimate | What annual output is forecast, and what roof, shade and weather assumptions were used? | Two companies can forecast different output for similar equipment if their assumptions differ. |
| Equipment | Which panel, inverter and battery models are included? | Specific model information lets you verify compatibility, warranty terms and replacement options. |
| Installation scope | Who handles permits, utility paperwork, inspections and any roof work? | Work left out of the contract can become an unexpected cost or delay. |
| Price and financing | What is the cash price, and what is the total cost under the proposed payment plan? | A low monthly payment may not represent the lowest overall cost. |
Use the table as a starting point, not a scoring system. A lower-priced proposal may exclude work that another includes, while a larger system may not be suitable if it produces more electricity than you can use economically. Have each company explain differences in writing before comparing the bottom-line figures.
System size should be based on both your electricity use and the roof’s ability to produce power. Provide bills covering a full year if you have them, because seasonal changes can be significant. If your household is likely to use more electricity soon, explain why: an installer can then show how that possibility affects the design instead of assuming today’s usage will stay constant.
Ask how the proposed panel layout accounts for roof orientation, shading, usable roof space and any obstructions. Also ask whether the installer has assessed the roof’s condition. If repairs or replacement may be needed, clarify whether they are included, who will do the work and whether solar equipment would need to be removed for later roof work.
Look beyond the system’s stated capacity. The proposal should include an estimate of annual electricity production and explain the assumptions behind it. Compare the estimates from each company and ask about large differences. A forecast is not a production guarantee unless the contract specifically defines a guarantee, its measurement period and the remedy if it is missed.
Consider how the system will interact with your utility. The amount you can save depends partly on how electricity is credited when the system exports more than the home is using. Billing arrangements, fixed charges and export compensation vary by location and can change. Ask the company to identify the assumptions it used and check them against your utility’s current rules before relying on a savings estimate.
Marketing descriptions such as “premium panels” or “high-efficiency system” are not enough to compare equipment. Ask for the manufacturer and model of each major component, along with the product and workmanship warranties that apply. If a proposal allows substitutions, find out what can be changed, who approves the replacement and whether the price or warranty changes with it.
The inverter converts the panels’ direct-current electricity into the form used in the home. Inverter types and configurations differ, and the appropriate design depends on the roof layout and system plan. Ask the installer to explain why its proposed configuration suits your roof, what monitoring is included and who you contact if the system reports a fault.
A battery is a separate decision, not an automatic upgrade. It may suit a homeowner who wants backup during outages or who has a reason to store energy for later use, but the value depends on the system’s configuration, household needs and local electricity rules. Ask what the battery is intended to power, how it operates during an outage, what equipment is required and what the proposal assumes about its use. A battery’s stated capacity alone does not explain how long it can support your home.
Request separate pricing for solar-only and solar-plus-storage options. That makes the added cost easier to evaluate and helps avoid treating a battery as necessary when your main goal is reducing electricity purchases.
Find out who will actually perform the work. The company presenting the proposal may use its own crews, subcontractors or a mix of both. Ask who is responsible for the installation, who supervises the job and which company handles problems after commissioning. If several businesses are involved, their responsibilities should be clear in the contract.
Check that the written scope covers the work needed to complete the project, including system installation, electrical work, permitting, inspections and utility interconnection steps where applicable. Ask what is excluded, how unforeseen roof or electrical work is priced and whether you must approve a change order before additional work begins. Do not rely on verbal assurances that a detail will be “handled later.”
Separate the different warranty promises. Panels, inverters and batteries may have manufacturer warranties, while the installer may offer a workmanship warranty. Roof penetrations or other roof-related work may have separate terms. Ask who submits a claim, whether labour or removal and reinstallation is covered, and what process applies if the original installer is no longer available. Get the answers in the contract or warranty documents rather than relying on a salesperson’s summary.
Solar energy companies may offer a cash purchase, a loan, a lease or a power purchase agreement. These arrangements differ in ownership, payment structure and responsibility for equipment. Compare the total obligation and contract terms, not just the first monthly figure.
| Payment option | What to compare | Potential fit | Important limitation |
|---|---|---|---|
| Cash purchase | Installed price, included work and any separate service costs | Homeowners who can pay upfront and want to own the system | Requires the largest upfront payment; savings still depend on production and utility billing. |
| Solar loan | Interest rate, fees, term, payment schedule and total of payments | Homeowners who want ownership but prefer to spread the cost | Financing charges can make the total cost higher than the cash price. |
| Lease | Payment schedule, escalations, service responsibilities and transfer terms | Homeowners who prefer not to own the equipment directly | Contract terms can affect a home sale, system changes and roof work. |
| Power purchase agreement | Price paid for generated electricity, rate changes, term and production terms | Homeowners considering a third-party-owned system | The payment is tied to the agreement, so compare its full terms with utility costs and other offers. |
For a loan, ask for both the cash price and the financed total, including fees and any payment changes. For a lease or power purchase agreement, identify who owns the equipment, who is responsible for repairs and how the agreement can be transferred if you sell the home. Ask about any scheduled increases in payments and what happens if you need roof work.
Have the company show how incentives are treated in its quote. Eligibility and rules depend on the incentive and the homeowner’s circumstances, so do not treat a projected credit or rebate as guaranteed savings. Verify current requirements with the relevant government or utility source and, for tax matters, a qualified tax professional. Be cautious if a proposal assumes you will receive an incentive without explaining the conditions.
A projected savings number is a calculation based on assumptions, not a promise that your bills will fall by that amount. Ask the company to show the estimated system production, the portion expected to be used in the home, the value assigned to exported electricity and any assumed rise in utility rates. Make sure the estimate distinguishes electricity-bill savings from payments for the system.
Check whether the forecast includes utility charges that remain even after solar is installed. Ask how the model treats seasonal production, system degradation, equipment downtime and any battery. If two proposals use different assumptions about future rates or export credits, compare them using the same assumptions where possible. If a company cannot explain its calculations in plain language, its headline savings figure is difficult to evaluate.
Do not assume that a system designed to match annual household use will eliminate every bill. The timing of solar production and household consumption, along with local billing rules and fixed charges, affects the result. Ask for an estimate of what you may still owe the utility and which parts of that estimate can change.
Verify that the business and the people doing the work meet the licensing and insurance requirements that apply in your area. Ask for the installer’s legal business name, the name of any subcontractor and evidence of relevant insurance. You can also request references for projects with similar roof conditions or system features, rather than relying only on general testimonials.
Read the complete contract, including attachments and financing documents. Confirm the final system design, equipment models, price, payment schedule, installation scope, warranties and estimated production assumptions. Check how the contract handles cancellations, delays, design changes, failed inspections, utility approval and work that costs extra. The specific rights and procedures vary by location, so review the terms that apply where you live.
Pause if the salesperson pressures you to sign immediately, promises guaranteed savings without clear written terms, avoids naming equipment models or dismisses questions about total cost. A proposal should give you enough information to compare it with alternatives. If a claim about savings or incentives is central to the offer, ask for the calculation and verify the underlying assumption independently.
Keep the proposals and your comparison notes together. If one company changes its design or price after a site visit, ask for a revised written quote so you are not comparing an updated offer with an outdated one.
There is no fixed number, but comparing more than one proposal can reveal differences in design, assumptions and contract terms. Focus on proposals that use the same household information and clearly identify the installer and equipment. An extra quote is less useful if it cannot be compared on a consistent basis.
Not automatically. First check whether the proposals include the same equipment, installation work, warranties and financing assumptions. A low price may be a good fit if the scope is complete, but an unexplained price gap deserves clarification before you decide.
A company can provide a forecast, but actual savings depend on system output, household use, utility billing and other assumptions. If an offer includes a performance or production guarantee, read the contract for how performance is measured and what remedy applies. A forecast alone is not a guarantee.
No. A battery adds storage and may provide backup functionality when the system is designed for it, but it also adds equipment and cost. Compare a solar-only proposal with a separate storage quote and decide whether the battery’s stated purpose matches your household needs.
The answer depends on the agreement. A lease or power purchase agreement may require a transfer process, while a loan remains subject to its own repayment terms. Ask each company to explain the sale, transfer or payoff procedure in writing before signing.
Choose the proposal you can explain from system design through final payment. Before committing, make sure the equipment, production assumptions, installation duties and contract terms are clear, and verify the local utility and incentive details that affect your estimate. That comparison is more useful than choosing solar energy companies by a savings headline alone.
