kWh daily versus monthly
Daily charts expose shading events; monthly totals smooth emotional noise. Use daily to debug; monthly to budget.
Fields in your inverter app
DC volts/amps per string, AC power, event logs — each answers different questions. Spikes without clouds might be cloud edge enhancement; flatlines might be communication drops, not zero generation.
Seasonal expectation bands
Compare winter against prior winter, not against July — seasonal normalization keeps mental health intact.
When to raise an alarm
Weeks of 50% underperformance versus model with clear skies warrants a ticket — intermittent dips may be weather. Photography helps engineers pre-diagnose.
CT clamps versus meter truths
Monitoring CTs occasionally disagree with fiscal metering — treat app totals as directional, not forensic accounting. Cross-check quarterly against supplier data when debugging “missing” kWh.
After inverter replacement, recalibrate monitoring if offered — firmware defaults sometimes assume old hardware personality traits.
Nameplate kWp vs real-world kWh
A “5 kWp” array rarely sustains 5 kW AC output for long — clipping, temperature, wiring losses and horizon shading chip peaks. Monthly kWh should track installer forecasts within reasonable bands, not sit at nameplate maths multiplied by sunlight wishes.
Per-string comparisons for shade detectives
If one string chronically underperforms a parallel string on identical orientation, suspect partial shading, connector resistance or a weak module. Symmetrical dips on both often mean weather, not fault — context saves unnecessary truck rolls.
Cross-check export against supplier reads
Inverter dashboards show inverter-relevant data; fiscal export credits follow meter registers your supplier reads. Quarterly reconciliation catches CT clamp orientation mistakes before they become twelve-month tax of confused spreadsheets.
Degradation curves and year-two psychology
Manufacturers promise slow annual % loss — early years can look flat, then a modest step appears. Compare year-one July versus year-three July, not July versus December, when diagnosing existential dread about “dying panels.”
Professional cleans after pollen tsunami weeks sometimes recover a few percentage points — log before/after production to see if fees were worthwhile or merely emotionally soothing.
Inverter error codes: photographed, not paraphrased
Support engineers adore photos of exact codes — “beeping sadly” wastes everyone’s Tuesday. Note grid voltage at fault time if displayed; DNO quirks masquerade as panel failures occasionally.
Annual benchmarks that survive marital debate
Agree one reference number: expected annual kWh ±10%. Revisit after year one with actual shade notes — models improve when fed reality.
Firmware updates: blessing and curse
Updates fix bugs and occasionally introduce logging pauses — read release notes like grown-ups, schedule updates outside holiday export weeks if paranoid.
Talking to relatives about your graphs
Relatives will glance at July peaks and declare genius or disaster — teach them seasonal baselines before Christmas arguments cite incomplete screenshots. A printed annual summary beats improvising numbers after mulled wine.
When string graphs diverge, note time of day — shade moves; if divergence holds all day across weeks, escalate with photos rather than hope.
Keep a simple spreadsheet: month, fiscal generation total, app generation total, notes — two seasons of data trains intuition free from vendor UI whims.
Supplier portals versus inverter apps
Monthly statements from utilities show credited export — reconcile against inverter totals knowing timing differs. A £14 export line might aggregate weeks your app shows separately — mismatch is not always theft, sometimes lag.
Export can appear on a different page than import — humans miss tabs; print-friendly PDFs beat phone browsers during phone calls with offshore call centres.
When generation looks fine but credits do not
Metering registration delays export payment despite healthy kWh on roof — escalate politely with dates, MCS numbers and DNO confirmation emails. Paper trails beat tone.
If you upgraded meter types mid-year, expect one chaotic statement — flag anomalies early rather than absorbing mystery rounding.
Understanding clipped summer peaks
Flat-topped midday curves often mean inverter limiting — not panel death — compare AC limit against DC nameplate. Occasional clipping can be economically rational; constant clipping might suggest mismatch worth discussing.
Log one sunny week annually as “reference healthy” — five years later you will treasure that innocence when comparing degradation trends politely with manufacturers.
If you add batteries, learn new dashboard tabs — import/export net views differ from gross DC production; arguments with partners require shared vocabulary.
Irradiance benchmarks without religion
Local benchmark years differ — compare your roof against installer promises using the same weather reference, not against cousin Dave’s “perfect” Bournemouth holiday home stats unless your postcode magically teleported south.
Reserve engineer visits for sustained anomalies — intermittent wobbles often trace to passing cloud edge effects your eyes forgot noticing.
CSV exports for nerds and accountants
Many inverters allow CSV downloads — yearly archives beat screenshots when warranty teams request longitudinal evidence politely.
Store files with naming like 2026-04-generation.csv — future you searching laptops will whisper thanks.