Check qualifications and local fit
Ask who will survey, design and install the system, and what qualifications are required where you live. Verify licenses or registrations with the relevant local authority rather than relying on logos or a salesperson's assurance.
Ask whether the proposed design accounts for roof condition, shade, electrical equipment, utility connection and permitting. If a site survey has not happened, find out which details remain provisional and how they could affect cost or layout.
Compare written proposals line by line
Review system size and equipment model numbers, estimated production and assumptions, installation scope, exclusions, timeline, payment terms, warranties, monitoring and service responsibilities. Confirm who handles permits, inspection and interconnection.
Compare like with like. Ask how an alternative design changes the scope and request any verbal promise in writing. Read the complete contract, including cancellation and change-order terms, before signing.
Assess communication and aftercare
Notice whether questions receive direct, documented answers and whether there is time for independent review. Ask how to reach support after installation, who handles warranty claims and what records you will receive.
A trustworthy comparison does not depend on urgency. You can seek multiple bids, ask for references where available and research complaints through appropriate local channels. If the explanation does not match the contract, pause and clarify before proceeding.
This checklist is educational, not an endorsement of any provider or a substitute for checking local licensing, consumer-protection rules and contract terms.