How to choose · Solar panels
How to choose a rooftop solar installer
Last updated 25 October 2026 · 2 sources listed · Reading time about 3 minutes
Short answer
Judge installers on certification, the quality of the site assessment, equipment transparency, warranty structure and who handles grid connection and paperwork. A good quote follows a roof inspection or detailed imagery, names components, explains shading and orientation losses, and states who supports the system if the installer closes. Schemes and rules vary by country, so check your energy agency's accreditation list.
Who this is for: A homeowner collecting quotes for rooftop solar and trying to separate competent installers from sales-led ones.
What to evaluate
Accreditation and licensing
Many jurisdictions require electrical licensing or scheme membership for grid-connected work, and some incentives depend on it.
How to check: Ask for the licence or scheme number and verify it on the official register run by the relevant agency.
Quality of the site assessment
A design built on a map view alone can miss shading, roof condition or switchboard limits.
How to check: See whether someone inspected the roof, the electrical board and the cable route, or used a detailed shading analysis.
Component transparency
Panel, inverter and mounting choices drive durability and support, and vague quotes hide substitutions.
How to check: Request the model names of panels, inverter and racking and confirm each has a current datasheet and local certification.
Warranty structure
Product, performance and workmanship warranties are separate, and only some survive an installer's closure.
How to check: Ask which warranty each party holds and whether there is insurance-backed cover for the workmanship.
Grid connection handling
Utilities often require approval before switch-on and may limit export or system size.
How to check: Ask who submits applications, what the approval timeline typically is, and what happens if the utility refuses.
After-sales monitoring and support
A system that quietly underperforms for years wastes the investment.
How to check: Find out how faults are reported, what monitoring is included, and the response expectation for a failure.
Comparison
| Installer type | Good when | Watch out for |
|---|---|---|
| Local specialist firm | You want accountable on-site staff and flexible design | Smaller balance sheet if a warranty claim arises years later |
| National retail installer | You value standard processes and brand backing | Sales pressure and subcontracted crews |
| Developer or builder package | Solar is bundled with a build or renovation | Limited choice of equipment and pricing opacity |
| Group-buy scheme | A community or council has vetted installers | Fixed designs that may not suit an awkward roof |
Decision worksheet
Rate up to three options against this guide’s own criteria. It runs in your browser and saves only on this device. It is a thinking aid, not a recommendation.
1. Have you checked each criterion?
0 of 6 criteria checked.
2. Compare options (0 = fails or unknown, 3 = meets it well)
| Criterion | |||
|---|---|---|---|
| Accreditation and licensing | |||
| Quality of the site assessment | |||
| Component transparency | |||
| Warranty structure | |||
| Grid connection handling | |||
| After-sales monitoring and support | |||
| Total (max 18) | 0 | 0 | 0 |
Questions to ask before you commit
- Who will physically install the system, employees or subcontractors?
- Which specific panel and inverter models are in the quote?
- What are the product, performance and workmanship warranties, and who stands behind each?
- Does the design account for shading from trees or neighbouring buildings through the seasons?
- Who applies for grid connection and any local permits?
- What happens if my switchboard needs upgrading, and is that included?
- How is the system monitored and who responds to faults?
- Can I speak to a customer with a similar system of some age?
Typical trade-offs
Choose the installer with the lowest quote
- Upside
- Reduces upfront outlay
- Downside
- May use lower-grade components or thin warranty support
Choose a long-established local firm
- Upside
- Stronger reputation and local service
- Downside
- Capacity limits may extend lead times
Accept a bundled finance offer
- Upside
- Convenient single process
- Downside
- Hard to compare the system cost separately from the credit terms
Common mistakes
- Signing on the day of a sales visit; ask for a written quote and compare at least two others.
- Accepting a quote without component model names, leaving room for substitution.
- Assuming the installer will cover grid approval without it being written into the contract.
- Ignoring roof age, so panels go on a roof that needs replacing soon afterward.
- Treating a monitoring app as a warranty; it only reports, it does not repair.
Related questions
How do I verify that an installer is properly accredited?
Ask for the licence or scheme registration number and check it on the official register of the agency or industry body that runs the scheme in your country. Some incentives and grid approvals depend on the work being done by a registered professional, so a mismatch can cost you later. If the installer cannot give a number or the register shows no match, treat that as a red flag.
Should the installer inspect my roof in person?
A site visit is better practice, because it can reveal roof condition, access, shading and the capacity of the electrical board. Remote designs from satellite imagery can be adequate for simple roofs but miss details. At a minimum, ask how the installer assessed shading and the switchboard, and whether the design will be revised after the inspection before installation.
What happens to the warranty if the installer goes out of business?
Manufacturer product warranties usually continue, but claiming may be harder without a local agent. Workmanship warranties depend on the installer unless there is insurance or a scheme-backed guarantee. Ask whether such cover exists and how to claim. Keep the contract, serial numbers and commissioning certificate in one place.
Are group-buy programmes safer?
They can reduce risk because someone has vetted installers and set standard terms, but you still need to check the contract. Designs may be generic, so confirm that your roof was assessed specifically. Look at who runs the programme, how complaints are handled, and what recourse you have if work is poor.
Sources and further reading
These pages were reachable when we last checked. They informed definitions and rules referred to above; they do not endorse this guide. Where rules differ by country, check the authority for your location.
- Homeowner's guide to going solar — U.S. Department of Energy, retrieved 27 October 2026
- Solar Energy — U.S. Department of Energy, retrieved 27 October 2026
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