How to Read Your Solar Generation Meter

Your solar generation meter measures how much electricity your panels produce. It's separate from your main electricity meter and is your proof of generation for export payments and performance monitoring.

Where to Find Your Generation Meter

Your generation meter is typically located:

• Next to your inverter — in the garage, utility room, or under the stairs
• Near your consumer unit (fuse board) — mounted on the wall nearby
• In a meter cupboard — if your main meters are in a cupboard, the generation meter may be alongside them

It's a small device — usually about the size of a pack of cards — with a digital LCD display. It may be labelled "generation meter," "solar meter," or simply show a kWh reading.

If you can't find it, check your installation paperwork. The MCS certificate or handover documents should describe its location. If all else fails, follow the cable from your inverter — the generation meter is wired into the AC output side.

Reading the Display

Most generation meters show a cumulative total in kilowatt-hours (kWh). This is the total electricity your panels have ever generated since the meter was installed.

Example reading: 12,458.3 kWh

This means your panels have generated 12,458.3 kWh since installation. If your system was installed 3 years ago, that's roughly 4,150 kWh per year — reasonable for a 4kW system.

Multiple Readings

Some meters cycle through several readings if you press a button or wait:

• Total generation (kWh): The main cumulative figure
• Current power (W or kW): Real-time output right now
• Daily generation (kWh): Today's total (some meters only)

The total generation reading is the one you need for performance tracking and export payment submissions.

How to Track Performance

Monthly Reading Method

Take a reading on the same day each month and record it:

Subtract last month's reading from this month's reading to get monthly generation.

What's Normal?

Monthly generation varies dramatically by season. For a 4kW system in the Midlands:

If your readings are consistently 20%+ below these ranges, something may be wrong — see the troubleshooting section below.

Generation Meter vs Smart Meter vs Inverter Reading

You may have multiple sources of generation data:

Generation Meter

Physical meter near the inverter. Shows total generation. Required for some SEG schemes.

Smart Meter

Your main electricity smart meter measures import and export but doesn't directly measure generation. However, generation = import reduction + export, so the data can be derived.

Inverter Display/App

Most modern inverters have built-in monitoring (GivEnergy app, Solis Cloud, etc.) that shows generation in real time and historically. This is usually the most convenient source.

Which to trust? They may show slightly different numbers because of conversion losses and measurement tolerances. The generation meter is the official figure for SEG claims. The inverter app is the most convenient for day-to-day monitoring.

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Submitting Readings for SEG Payments

If you're on a Smart Export Guarantee tariff, you may need to submit generation meter readings for export payment calculation. The process depends on your energy supplier:

• Octopus Energy: Usually uses smart meter export data — no manual submission needed
• Other suppliers: May require quarterly or annual generation meter readings submitted online or by phone

Check your SEG contract for the specific requirements. See our claiming SEG payments guide for full details.

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Troubleshooting Low Readings

If your generation is consistently below expectations:

Quick Checks

• Is the inverter on? Check the display or indicator lights. An off inverter means zero generation.
• Is there an error code? Inverters display fault codes — check the manual or manufacturer's website.
• Are panels dirty or shaded? New tree growth, building work, or accumulated dirt can reduce output.
• Has the weather been unusually poor? Compare your reading against the national average for the period.

Deeper Investigation

• Compare with neighbour's systems — if available, significant differences suggest a problem with your specific system
• Check inverter logs — most inverters record daily generation and can show patterns
• Check individual string performance — if you have multiple strings, uneven output suggests a panel or wiring issue
• Call your installer — if generation is 30%+ below expectations with no obvious cause, professional investigation is warranted

Do All Systems Have a Generation Meter?

Not necessarily. The requirement depends on when your system was installed and whether you're claiming export payments:

• Feed-in Tariff systems (pre-2019): All have generation meters — required for FiT payments
• SEG systems (2019+): May have a generation meter, or may rely on smart meter export data
• Self-consumption only (no export scheme): May not have a separate generation meter if the inverter provides monitoring

If you don't have a generation meter and want to track performance, your inverter's built-in monitoring is usually sufficient. If you need one added (for SEG claims), your installer can fit one for £100–£200.

Regular meter reading is a simple habit that keeps you informed about your system's health. A 5-minute monthly check can catch problems early, before they become expensive.

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