Size for useful energy, not the largest roof coverage
The most valuable solar electricity is often the electricity your business uses directly. A larger system can generate more energy, but that does not automatically mean a better return if most of the additional output is exported at a lower rate.
Start with your minimum daytime demand across a typical working week. Include weekends, seasonal changes and shutdown periods rather than designing around a single busy day.
What a designer needs to assess
A tailored proposal combines energy data with a physical and electrical assessment of the property.
- Interval consumption data and current electricity tariffs, including demand charges where applicable.
- Usable roof area, orientation, shading, structural condition and safe access.
- Switchboard capacity, existing equipment and the local network's connection and export requirements.
- Likely future loads such as electric vehicles, added machinery or extended operating hours.
Choose the installation type around the site
Rooftop solar uses existing building space and is a common choice for commercial premises. Ground-mounted systems may suit sites with available land or unsuitable roofs. Building-integrated options incorporate solar into the building itself and require closer coordination with construction design.
Roof area is only one constraint. Electrical upgrades, network approval, shading and structural work can influence the practical system size and installed cost.
Ask for a comparison before committing
Request more than one capacity option with projected annual generation, on-site consumption, exports and savings shown separately. Check that the assumptions match your working hours and the network limits for your address.
If expansion is likely, discuss inverter capacity, spare roof space and equipment compatibility now. A future battery should be considered using your surplus solar and later demand, not simply added because a larger solar package is available.