kWp (kilowatt peak)The maximum power output of a solar panel system under ideal test conditions. A 4kWp system is a common size for a 3-bedroom UK home.kWh (kilowatt hour)A unit of energy. Your electricity bill is measured in kWh. One kWh is roughly enough to run a washing machine for one cycle.Solar irradianceThe amount of solar energy hitting a surface, measured in kWh per square metre per year. Higher irradiance means more electricity generated.InverterA device that converts the direct current (DC) electricity produced by solar panels into alternating current (AC) that your home uses. Usually mounted near your fuse board.Smart Export Guarantee (SEG)A UK government scheme that requires energy suppliers to pay you for surplus solar electricity you export to the national grid.Self-consumptionThe percentage of your solar electricity that you use directly in your home rather than exporting to the grid. Higher self-consumption means greater savings.Feed-in Tariff (FIT)A former UK government incentive that paid solar panel owners for generated electricity. It closed to new applicants in March 2019 and was replaced by the Smart Export Guarantee.MCS (Microgeneration Certification Scheme)The UK quality standard for small-scale renewable energy installations. An MCS-certified installer has been independently assessed and is required for SEG eligibility.Payback periodThe time it takes for savings from your solar panels to equal the original installation cost. After payback, all savings are pure benefit.Battery storageA home battery that stores excess solar electricity for use when the sun is not shining, typically in the evening. Increases self-consumption from about 50% to 80%.Panel degradationThe gradual reduction in solar panel output over time. Typical panels degrade by about 0.5% per year, meaning they still produce around 87% of their original output after 25 years.Roof orientationThe compass direction your roof faces. South-facing is ideal for solar, but south-east, south-west, east, and west-facing roofs are also suitable.PVGISThe Photovoltaic Geographical Information System — a free tool from the European Commission that provides solar radiation data and performance estimates for any location in Europe.Core Web VitalsGoogle's metrics for page experience — loading speed, interactivity, and visual stability. Fast-loading pages tend to perform better in search results.Grid connectionThe link between your home's electrical system and the national electricity grid. Solar panels feed into this connection, and any surplus is exported.