Reading your solar panel meters

Understanding how to read your solar panel meters is crucial for UK homeowners with solar panels. Accurate meter readings are vital for monitoring your system's performance, ensuring you are paid correctly for the energy you export, and making informed decisions about your energy consumption. This guide will walk you through the different types of solar meters, how to read them, and what the numbers mean for your home.

Understanding your solar panel meters

A typical solar panel system in the UK involves at least two types of meters: a generation meter and an export meter. Increasingly, smart meters are consolidating these functions, but understanding each component is key to managing your solar energy effectively. Confusing import readings with export or generation readings is a common pitfall.

What is a solar generation meter?

A solar generation meter measures the total amount of electricity your solar panels produce. This reading is crucial for older systems that receive Feed-in Tariff (FiT) payments, as these payments are based on your total generation. For all systems, it helps you track how well your panels are performing over time. It's essentially a mileage counter for your solar energy output, typically found near your inverter or fuse box.

What is a solar export meter?

An export meter measures the surplus electricity your solar panels send back to the National Grid. This is particularly important for newer installations, as the Smart Export Guarantee (SEG) mandates that licensed electricity suppliers pay small-scale low-carbon generators for this exported energy. Your export meter reading directly impacts how much you earn from your solar panels.

How smart meters handle solar data

Smart meters are designed to integrate import, export, and sometimes generation data into a single device. They can automatically send readings to your energy supplier, removing the need for manual submissions. However, navigating their displays to find specific solar-related readings often requires understanding particular codes or cycling through various screens. Many homeowners find that a smart meter installation can significantly improve their ability to track energy flows.

How to read a solar generation meter

Reading your solar generation meter is straightforward once you know what to look for. These meters universally record readings in kilowatt-hours (kWh).

Reading digital generation meters

Most modern generation meters are digital. They typically have a display screen that shows a cumulative kWh reading. This number represents the total electricity your panels have generated since installation. To get a reading, simply note down the full number displayed, usually ignoring any digits after a decimal point unless specifically instructed otherwise by your provider. Some models might have a button to cycle through additional information, such as current power output, but the cumulative kWh is the primary figure for tracking generation.

Reading mechanical generation meters

Older solar installations might have mechanical generation meters, which resemble traditional electricity meters with rotating dials. To read these, note the number indicated by each dial from left to right. If a pointer is between two numbers, always record the lower number. If it's directly on a number, check the dial to its right; if that dial has passed zero, use the higher number for the current dial.

Instructions for specific UK models

Common solar generation meter brands in the UK include Landis+Gyr, Elster, and Secure. While specific models vary, the principle remains the same: locate the cumulative kWh reading. For instance, some Landis+Gyr meters might require pressing a button to wake the display and cycle through options until the generation total is shown. Elster meters, such as the A100C, will typically display the cumulative energy produced in kWh. For Secure Liberty 100 meters, you might press '6' or '9' on the keypad until 'EXP kWh' appears, though this is often for export rather than generation. Always refer to your meter's manual or your installer's guidance for precise instructions. For general guidance on reading electricity meters, you can refer to our guide on how to read your electricity meter.

How to read a solar export meter

Your solar export meter tracks the electricity you send back to the grid. This can be a dedicated meter or a function integrated into your main electricity meter.

Dedicated export meters

If you have a dedicated export meter, it will typically look similar to a generation meter, often digital, displaying a cumulative kWh figure. This number increases as you export more electricity. Record the full number shown on the display.

Export readings on your main electricity meter

Many homes with solar panels now have smart meters that handle both import (electricity taken from the grid) and export readings. These meters often cycle through different displays automatically or require you to press a button to view various readings. Look for labels like "Total Act. Export", "EXP kWh", or "Cum. EXP.".

Deciphering smart meter readings with solar panels

Smart meters can simplify energy management, but their multi-screen displays can be confusing when you have solar panels.

Identifying import vs export on smart meters

On a smart meter, import and export readings are usually distinct. Import readings might be labelled "IMP" or "Total Act. Import" and show the total electricity drawn from the grid. Export readings will typically be labelled "EXP" or "Total Act. Export" and indicate the total electricity sent to the grid. Some meters may also show arrows on the display; an arrow pointing right usually means importing power, while an arrow pointing left indicates exporting power.

Common smart meter display codes for solar

Different smart meter models use various codes to display solar-related data.

• Landis+Gyr E470: To find your export reading, you often need to wake the display (if asleep) and then press and hold the 'A' button until 'Time' appears. Continue pressing 'A' to cycle through the screens until you see "Total Act. Export".
• Elster (e.g., AS300P, AS302P): You might need to press and hold a grey middle button or an 'A' button to access a menu. Then, navigate through options like 'General' or 'Registers' until you find 'Cum. EXP.' or 'Export'.
• Secure liberty 100/101: For export readings, pressing '9' on the keypad typically brings up "EXP kWh".

How to know if your solar panels are exporting

Beyond checking your meter, there are other ways to tell if your solar panels are exporting:

• Smart meter display: Look for an arrow pointing left on your smart meter's display, indicating energy flow to the grid.
• Inverter display: Many solar inverters show real-time generation. If your generation exceeds your home's current consumption (which you might gauge from an in-home display), you're likely exporting.
• Energy supplier app: If you have a smart meter and an export tariff, your energy supplier's app (like Fuse Energy's) may provide data on your exports.

Interpreting your solar meter data

Understanding your meter readings empowers you to manage your energy more effectively and maximise the benefits of your solar panels.

Understanding kWh readings and what they mean

All solar-related meter readings are recorded in kilowatt-hours (kWh). This is the standard unit for measuring electricity consumption and generation. One kWh is the amount of energy used by a 1,000-watt appliance running for one hour. The average UK home uses around 2,500 kWh of electricity per year, which is roughly 6.8 kWh per day. By comparing your generation and export readings to your import and overall household consumption, you can gain a clear picture of your energy balance. For a deeper dive into this unit, read our article on what is a kilowatt-hour (kWh).

Monitoring system performance and efficiency

Regularly checking your generation meter helps you track your system's performance. A consistent drop in generation might indicate an issue with your panels or inverter. By comparing your generation to your export, you can also calculate your self-consumption - the amount of solar energy you use directly in your home rather than sending it to the grid. Maximising self-consumption often leads to greater savings.

Maximising your Smart Export Guarantee (SEG) earnings

The SEG requires licensed electricity suppliers to offer tariffs for exported electricity. Accurate export meter readings are fundamental to ensuring you receive correct payments. SEG tariffs came into force on 1 January 2020, replacing the Feed-in Tariff (FiT) scheme for new installations. Ofgem regulates the SEG, ensuring suppliers offer tariffs to eligible generators and that payments are made fairly. Keeping a consistent record of your export readings allows you to verify your payments and ensure you're on the best possible tariff.

Troubleshooting common solar meter reading issues

While meters are generally reliable, you might encounter issues that prevent you from getting a clear reading.

Blank or unresponsive meter displays

If your meter display is blank or unresponsive, first check if it has a 'wake up' button. Many digital meters enter a sleep mode to conserve power. Pressing and holding a button for about 10 seconds typically wakes the display. If the screen does not turn on after that, the issue requires further investigation. If the problem persists, contact your energy supplier.

Inconsistent or unexpected readings

Inconsistent readings could be due to several factors:

• Reading error: Double-check that you are reading the correct register (generation, import, or export) and noting down the full number accurately.
• System performance: A sudden drop in generation might be due to shading, dirt on panels, or an inverter fault.
• Smart meter connectivity: If your smart meter is offline, readings might be estimated, leading to discrepancies when it reconnects.

What to do if you suspect a meter error

If you suspect a meter error, such as a faulty display or wildly inaccurate readings, the first step is to contact your energy supplier. They can perform remote diagnostics or arrange for an engineer to inspect the meter. Do not attempt to tamper with the meter yourself.