Domestic solar PV

A domestic solar PV system has to fit the roof, work within the electrical supply and meet the DNO connection rules. Its value then depends on when it generates, how much electricity the home uses at the same time and the terms available for exported energy.

Home solar installation guide

The guide covers the roof survey, system design, grid-connection route, installation records and export application.

Home solar installation guide →

Solar generation, use and export

The array generates DC electricity and the inverter supplies AC to the home. Household loads, battery storage and the export connection determine how that electricity is used.

01
The array generates DC
Modules are arranged across one or more roof planes. Their rating describes output at defined test conditions, while the roof, weather and shade determine the energy produced on site.
02
The inverter supplies AC
A string inverter, microinverters or another suitable architecture converts DC into AC for the home. The design has to keep module voltage and current within the equipment limits.
03
The home uses what it needs
Solar supplies loads that are running at the time. Monitoring may show generation, household demand, import, export and battery power as separate measurements.
04
Surplus is stored or exported
A compatible battery can store some surplus for later use. Electricity that is not used or stored is exported through the grid connection. Payment for that export requires suitable metering and a supplier contract.

Roof layout, shade and structural constraints

Orientation and pitch change the timing and total of generation. Chimneys, dormers, trees and nearby buildings add shade. The structure, covering, wind exposure, fixing positions and safe access can remove parts of the roof from the layout even where a panel would physically fit.

East and west-facing roof planes can spread production across more of the day. Each plane needs its own yield inputs and the mounting system needs a structural design for the actual roof; a south-facing layout is not the only useful arrangement.

Orientation and pitch Shading analysis Roof loading survey

Survey evidence

Measured roof planes and a module layout that matches them
A recorded shade assessment, not a single daytime photograph
Roof condition and structural checks for the actual mounting loads
A planning and Building Regulations route for the property and UK nation
Any assumptions caused by inaccessible or concealed construction

Annual generation, self-consumption and export

An annual generation estimate describes the AC energy expected from the array. It does not say how much of that energy the home will use, how much a battery will retain or what exported electricity will earn.

Generation

Location, roof geometry, shade, module layout, inverter design and weather shape the energy produced. Compare estimates made from visible assumptions.

Performance estimates →

Use in the home

Solar replaces grid import only when generation and household demand overlap. Annual consumption totals cannot show that timing on their own.

Self-consumption estimates →

Storage

A battery moves some energy to a later time. Usable capacity, power, losses, reserve settings and tariff charging all affect the outcome.

Battery storage overview →

Export

Export needs the correct DNO record, metering and a supplier contract. SEG (Smart Export Guarantee) rates and commercial conditions are set by suppliers rather than by the array design.

SEG eligibility →

Roof, yield, equipment and connection details

The roof survey, annual generation estimate, equipment schedule and grid-connection route define different parts of the system. Panel count and wattage do not replace any of that evidence.

Roof and mounting

The array layout shows the roof planes and module positions. The survey and structural design provide the separate evidence for roof condition, loading, fixing approach and access constraints.

Roof loading survey →Roof hook and rail mounting →

Yield and shade

Annual generation should be calculated from the property, roof geometry and shade. Keep separate roof planes visible and distinguish generation from bill saving.

MCS PV performance estimates →Shading analysis →

Inverter and controls

The exact inverter, AC rating, string or MPPT (maximum power point tracker) arrangement and monitoring equipment define the conversion and control design. A later storage route depends on named compatible equipment.

String inverters →Hybrid inverters →

Connection and handover

Aggregate Registered Capacity determines the G98 or G99 route. Electrical, Building Regulations, MCS and DNO (distribution network operator) documents provide separate evidence where each applies.

DNO notification for PV →PV commissioning pack →

Solar guides