Start with the bills, the production data, and the agreement

If an existing solar system is not delivering the bill savings you expected, the answer is not automatically “add more panels” or “buy a battery.” Several different issues can produce the same disappointing bill. We begin by separating them before discussing equipment.

What we review

  • 12–24 months of utility bills, including annual true-up statements when applicable
  • Solar monitoring and inverter production records
  • Your current utility rate plan and export-credit rules
  • Loan, lease, PPA, or other financing obligations
  • Changes in household use, including EV charging, HVAC, pool equipment, additions, or new occupants
  • Known shutdowns, faults, shading changes, or equipment replacements

Questions the assessment should answer

  • Is the system producing as expected? Monitoring gaps, inverter faults, failed components, new shade, or soiling may reduce output.
  • Has electricity use changed? A system can perform normally while the home uses more energy than the original estimate assumed.
  • Did the rate plan or export compensation change? Production and bill savings are not the same measurement.
  • Were the original assumptions reasonable? Savings projections depend on future rates, usage, production, degradation, financing, maintenance, and tariff treatment.
  • Is there a contractual or warranty issue? The proposal, agreement, warranties, and promised production should be compared with the evidence.

A savings estimate is not a guarantee

We do not promise that solar will eliminate a utility bill, pay for itself, or keep a home powered during an outage. Grid-connected solar normally shuts down during an outage unless the system includes properly designed and commissioned equipment that is approved to operate in backup mode.

Any financial comparison should show its assumptions and use current customer, utility, equipment, and financing information. The California Public Utilities Commission specifically advises customers to ask how potential bill savings were calculated and notes that a savings estimate is not a guarantee.

The outcome: a staged improvement plan

After the evidence is organized, the next step may be monitoring repair, warranty follow-up, a rate-plan review, load management, equipment correction, storage, or no equipment purchase at all. Our rule is simple: preserve what works, correct what does not, and add only what moves you toward the outcome you actually need.

Your solar investment should work for you.

California Solar Consumer Protection Guide · U.S. Department of Energy Homeowner’s Guide to Solar

Reviewed August 8, 2026. Utility programs, tariffs, incentives, equipment availability, and regulations change; current details must be verified for each property.