| 1. Review a full year of electricity use | Collect electricity bills or interval-meter data covering all seasons. | Record monthly consumption in kWh. For example, 600 kWh per month averages about 20 kWh per day (600 ÷ 30). | A full year helps reveal seasonal changes and provides a more reliable starting point than a single bill. |
| 2. Check when electricity is used | Compare daytime, evening, and overnight usage where interval data is available. | List major loads such as air conditioning, water heating, cooking, and electric-vehicle charging, including their usual operating times. | Solar generation is typically greatest during daylight hours. Matching flexible loads to those hours can increase direct use of solar electricity. |
| 3. Identify changes in future demand | Account for planned additions or changes to household equipment and occupancy. | Note expected additions such as an electric vehicle, heat pump, or home extension; estimate their use separately from current consumption. | A system sized only for current usage may not suit future needs. Estimates should be based on expected operation, not equipment nameplate capacity alone. |
| 4. Review the roof and available solar area | Check roof orientation, slope, shading, usable area, and condition. | Record shaded areas and roof obstructions such as vents or skylights. Ask the installer to assess the roof structure and the condition of the covering. | Shade, orientation, and usable area affect the amount and layout of panels. Roof repairs may be more practical before installation. |
| 5. Confirm the grid connection details | Check the service type, supply voltage, phase arrangement, and main switchboard capacity. | Use the electricity meter, switchboard labels, or a qualified electrician to verify site details; do not assume all homes have the same connection. | Connection characteristics can affect equipment selection and installation design. Local utility rules determine which configurations are permitted. |
| 6. Ask about export limits and approval | Find out whether the local network operator requires an application or limits electricity exported to the grid. | Request written confirmation of the applicable export limit, approval steps, and any required inverter settings before installation. | Export conditions vary by location and network capacity. They can affect system design and the value of surplus generation. |
| 7. Compare system output with your usage and tariff | Review estimated annual generation, self-consumption, import rates, and export compensation. | Compare the installer’s generation estimate in kWh per year with your annual consumption. Check your current tariff for time-of-use rates and export credits. | Annual production alone does not show when power is available or how much will be used on site. Tariff details help buyers compare likely bill impacts. |