Questions to ask your solar installer

Two quotes with the same kWp can differ in everything else: yield, equipment quality, what is included in the price and support after commissioning. These questions help you compare offers like for like — ask them of every installer, including us.

Sizing and yield

1. How did you determine the plant size? A good answer refers to your consumption (bills, hourly data), not just roof area.
2. What share of generation will we consume ourselves, and how much goes to the grid? Ask for a month-by-month estimate.
3. What is the estimated annual yield, and from which tool/simulation? Ask about the assumptions: orientation, tilt, shading, losses, degradation.
4. Have you accounted for our approved connection capacity and the prosumer rules in our entity?
5. How will the plant affect billed peak demand and power factor? Is reactive power compensation needed?

Equipment and warranties

6. Which panel and inverter manufacturer and model? Ask for datasheets.
7. What warranties apply? Distinguish the product warranty (defects) from the performance warranty (how much power a panel must retain after a given number of years). Who handles warranty claims in BiH if the manufacturer has no local presence?
8. What is the expected inverter life and what does replacement cost? Inverters usually last less than panels.
9. Which mounting system is used and how is it fixed — does it penetrate the roof covering? Who is responsible for waterproofing?
10. Has the roof structure been checked, or does that need to be ordered separately?

Documentation, permits and grid connection

11. What documentation is included? Design, grid-connection approval application, connection agreement, documentation for the building/use permit.
12. Who manages the process with the distribution system operator and supplier?
13. How long does the whole process take until connection, and what does it depend on?
14. How is protection handled — surge protection, earthing, isolation devices, fire-safety requirements?

Installation and delivery

15. Who does the installation — your own team or subcontractors? How is health and safety ensured?
16. What is the delivery time and what could extend it?
17. What are the payment terms, and what happens if the deadline is missed?
18. What is the workmanship warranty?

Monitoring, maintenance and support

19. What monitoring do we get? App or portal, multi-user access, fault notifications.
20. How do we report a fault and how quickly do you respond? Ask for the answer in writing.
21. What do you recommend for maintenance and cleaning, and do you offer a maintenance contract?
22. What references do you have? Ask for sites of similar size and type, ideally with a client contact.

Finances

23. How did you calculate savings and payback? What electricity price did you assume, and are output degradation and inverter replacement included?
24. Can you prepare documentation for the bank if we finance with a loan or lease?

Warning signs

• A quote with no review of your bills and no site visit (except for very small, simple systems).
• A promise of “guaranteed” savings or yield without stated assumptions.
• Unclear responsibility for the grid-connection process.
• Warranties with no clear way to claim them in BiH.
• Sizing well above annual consumption with no explanation of how surplus will be settled.

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SHPP has been building solar plants since 2011 and is happy to answer every question on this list. Request a quote or start with our pre-installation checklist.