Making power on the roof since 2012

Eight solar panels, 1.96 kW in all, have sat on the south-facing front slope since February 2012, and ever since they have paid the household a Feed-in Tariff for every unit they generate: about £1,100 a year by the homeowner's account, roughly £15,000 so far, much of it reinvested in the house's other retrofit measures. In 2025 they made roughly 1,750 kWh, and a battery added in 2023 and 2024 can store power for later use. The household is also paid about £40 a year for the power the panels export.

What the panels pay

Since they were installed in 2012 the panels have paid the household a Feed-in Tariff for every unit they generate, whether or not the house uses it: about 49p a unit at the start, rising each year since, and about £1,100 a year now by the homeowner's account. On the panels' roughly 1,750 kWh that is about 63p a unit, a figure worked out from the £1,100, not read from a statement. Over the 14 and a half years since installation that adds up to roughly £15,000: about £14,000 if the payments rose steadily from the 49p start, about £16,000 if they had always been £1,100, so it is an estimate and not a statement. The household has reinvested much of that money in the other retrofit measures in these stories, which is why it comes first here. The scheme closed to new applicants on 31 March 2019, so a new installation cannot get one: this is one household's outcome, not a typical one. Separately, the roughly 300 kWh a year the panels send to the grid is paid for as exports, at 12 to 15p a unit on Octopus's Outgoing tariff: about £40 a year, estimated from the months since Octopus began paying for exports in autumn 2025. The story "How it was paid for" sets the tariff beside what the later measures cost.

What is on the roof

Eight Hyundai panels of 245 W each, 1.96 kW in all, sit in two rows of four on the front slope of the roof, beside the chimney stack at the party-wall end. The roof faces south, generally a well-placed direction for solar panels. The installation, quoted in February 2012, cost £6,269.26 including 5 percent VAT, long before the heat pump, the battery or the electric car charger.

What it did in 2025

The inverter's own chart in the SolaX app shows the panels making roughly 1,750 kWh in 2025: about 50 kWh in December and about 230 kWh in April, the best month. That works out at about 890 kWh for every kW of panels, for this house in this year. The figure is read by eye from the app's yearly chart, so it is approximate. Over the same year, 224.65 kWh of power went out to the grid, and exports are paid for: by the previous supplier until October 2025 and by Octopus since.

How it fits with the rest of the house

The panels make direct current, and an inverter in the loft turns it into the alternating current the house uses. That power runs the house first. A battery was added in two stages, 6 kWh in July 2023 and a further 3 kWh in October 2024, so that power can be stored and used later. The battery has its own inverter, in the rear yard. The heat pump is not directly connected to the panels or the battery, but it draws on the same supply. The electric car charger is on the same supply too, so on a bright day the car can be charged from the roof.

Why an older, small array still counts

A 1.96 kW array is a small one. What matters to the household is the power the panels make on a bright day, and a south-facing roof helps a small array make the most of it. In winter the panels make little (about 50 to 70 kWh a month from December to February) and the house leans on the grid. From May to August the SolaX app shows the house taking its least from the grid (read by eye from its chart).

Reading the SolaX app

The app's overview page shows a "Yield" of 3,395.60 kWh for 2025, about double the panels' own output. The figures suggest it adds the battery inverter's output (about 1,630 kWh) to the panels' (about 1,750 kWh), which would come to about 3,380 kWh. The app does not say so, so this is an inference. If it is right, solar power that went through the battery would be counted twice, while power the battery took from the grid would be counted once. The 1,750 kWh above is the panels' own figure.

Benefits

Paid for every unit generated since 2012: a Feed-in Tariff of about £1,100 a year by the homeowner's account (about 63p a unit), roughly £15,000 so far and much of it reinvested in the house's other retrofit measures, plus about £40 a year for exports (a legacy scheme, closed to new applicants in 2019: one household's outcome, an illustration of scale).
Free energy for the car: on a bright day the car can be charged from the roof, at no cost for the energy.
Power made on the house's own roof, without fuel or noise: roughly 1,750 kWh in 2025, which is about 300 kg of CO2e not drawn from the UK grid at its 2025 average (on-site solar counts as zero). An illustration, not a measurement.
A south-facing roof gets the most from a small array.
Working since 2012.

Limitations

This is one house in one year: how much a roof makes depends on its direction, tilt, shading and the weather.
The 2025 figure is read by eye from the app's chart, so it is approximate; it is not a meter reading.
Nothing here is a promise of output, saving or payback for another home.
The panel model and the roof's pitch are not recorded.
The Feed-in Tariff figure is the homeowner's approximate account of what they receive, not a statement, and the roughly £15,000 since 2012 is an estimate between the two cases in the story; the 63p a unit is worked out from it and the panels' output (read by eye). The scheme closed to new applicants on 31 March 2019, so it cannot be earned by a new installation.
The export income is an extrapolation: Octopus only began paying for exports in autumn 2025, so a full year of about 300 kWh is estimated from the months since.