FAQ
TL;DR: A 50 % self-consumption rate is “everything is correct” [Elektroda, 3301, post #17047684]; inverter totals usually read 1–5 % higher than revenue-grade meters [NREL, 2020]. Track 1.8.0 (imports) and 2.8.0 (exports) daily, subtract to catch errors.
Why it matters: Early comparison prevents six-month billing shocks and lost kilowatt-hours.
Quick Facts
• Inverter-to-meter deviation: typical 1–5 % [NREL, 2020]
• Self-consumption example in thread: 50 % [Elektroda, 3301, post #17047684]
• Add-on three-phase Orno meter cost: PLN 170 new, PLN 100–110 used [Elektroda, Jan_Werbinski, post #17052436]
• Reactive energy (Q1–Q4) not billed until approx. 2026 [Elektroda, cuuube, post #18171654]
• Phase-balancing test: 0.5 h, >⅓ load on one phase, watch 1.8.0 [Elektroda, 3301, post #18043981]
Why does my inverter show more kWh than the bidirectional meter exports?
The inverter counts every watt it produces, but the meter logs only what flows through it. Energy used instantly by appliances never reaches the meter, so exported 2.8.0 is lower. A 31 kWh gap on 62 kWh production matched 196 kWh household use in the thread [Elektroda, marcinbbb, post #17047628]
How do I calculate real household consumption?
Use: Consumption = Inverter production + 1.8.0 (imports) – 2.8.0 (exports) [Elektroda, Jan_Werbinski, post #17051898] This sums what was generated, adds grid energy taken, and removes what you sold back.
Is 50 % self-consumption considered good?
Yes. Grid operators and installers target 30–50 % for homes without batteries. The original poster reached 50 %, which was called “very good” [Elektroda, 3301, post #17047684]
What do meter codes 1.8.0 and 2.8.0 mean?
1.8.0 = total active energy imported from the grid; 2.8.0 = total active energy exported. Apator Smart EMU manuals confirm these designations [Apator Manual].
Does phase balancing affect my credits?
If your utility enables inter-phase balancing (PGE does), total three-phase power is settled, not each phase [Elektroda, kosmos99, post #18322484] Without balancing, one heavily loaded phase can draw while others export, raising 1.8.0.
How can I test whether balancing is active?
- Choose a sunny hour when PV is producing. 2. Connect a load >⅓ inverter power to one phase for 30 minutes. 3. If 1.8.0 barely rises, balancing works; if it jumps, balancing is off [Elektroda, 3301, post #18043981]
Why did my invoice show zero exported energy?
Possible causes: 1) Meter mis-configuration counting exports as imports [Elektroda, Leon444, post #18409436] 2) PV downtime—one user saw 0 kWh on the utility meter after six months because the inverter had stopped [Elektroda, 3301, post #18409758] Record daily readings to spot this edge case.
How accurate are inverter energy counters?
Field tests show inverters read 1–3 % high compared with Class 1 meters [NREL, 2020]. Forum users noted 9 kWh gaps on 400 kWh production (≈2.3 %) [Elektroda, RomanCitro, post #17248867]
What are Q1–Q4 reactive energy values on Smart EMU meters?
They log capacitive/inductive reactive energy in four quadrants. Current Polish tariffs ignore these values for residential prosumers until at least 2026, so they do not affect bills yet [Elektroda, cuuube, post #18171654]
How much does installing an independent consumption meter cost?
Single-phase units start at PLN 75, three-phase at PLN 170 new; used models sell for PLN 100–110 [Elektroda, Jan_Werbinski, post #17052436]
Could wiring losses explain large differences?
Yes, high cable resistance or loose connections between inverter and utility point can waste energy as heat. Losses above 2 % on short runs suggest a fault [IEC 60364]. A user fixed a mis-wired pole connection that caused abnormal meter gaps [Elektroda, RomanCitro, post #19681224]
What if the meter counts exports as imports?
Bills may jump by up to 95 %, as one user saw after meter replacement [Elektroda, Mietek_MK, post #18061207] Request a utility check; if the meter fails, the operator pays for the test—otherwise you cover ~PLN 120 [Elektroda, dario1965, post #18408509]
Can wrong country settings in the inverter lower exports?
Changing grid profiles mainly adjusts voltage and frequency trip points; it does not affect self-consumption share [Elektroda, 3301, post #18171586] Leave settings that match local grid standards to avoid shutdowns.
Why does my apparent consumption rise after PV installation?
Two reasons: 1) You use more appliances during daylight, assuming “free” power—forum users admitted this behavior [Elektroda, rokbok, post #19680661] 2) The previous meter may have under-registered load; the new smart meter is more accurate, revealing real demand.
When should I request a utility meter inspection?
Request if daily exports drop to zero despite sunny production, or if inverter and 2.8.0 diverge by >10 % for a week. Document readings and photos; utilities charge for successful tests only when the meter is accurate [Elektroda, 3301, post #18408521]
Daily checklist: How do I verify readings?
- Note inverter kWh at sunset.
- Record 1.8.0 and 2.8.0 on the utility meter.
- Next morning, compute self-consumption with the formula in Question 2. Three numbers should reconcile within 3 %.
