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Maintain playbook

Solar System Producing Less Than Expected

Separate normal variation from a real performance issue using like-for-like periods, monitoring evidence and a structured site handover.

Sources listedReviewed July 2026Our methodology
Safety boundaryRead first

Performance review does not require opening equipment or going onto a roof. Electrical testing and rooftop inspection are licensed-person work.

Field runner

Compare like with like

Stage 1 of 30/9 checked
Evidence handoff

Keep the evidence with the job

These device-local checks are working state, not evidence. Save actual readings, observations and the outcome in a job record.

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01

Compare like with like

  1. Compare similar weather, season and time windows rather than a single day against an annual promise.
  2. Check whether consumption, export limiting or battery charging explains the apparent difference.
  3. Confirm the monitoring portal is receiving complete data rather than estimating missing intervals.
02

Build the evidence

  1. Export or screenshot daily generation for the affected period and a known-good comparison period.
  2. Note new shade, soiling visible from ground level, network events and any recent electrical work.
  3. Record whether the loss affects a particular inverter, MPPT, string or phase.
03

Escalate clearly

  1. Send the installer the comparison, site details and exact monitoring symptoms.
  2. Ask for the design expectation and the measurement method used to assess the shortfall.
  3. Treat persistent faults, damage, heat, smell or unusual noise as a stop-and-escalate condition.
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