Start with measured demand
Use interval electricity data and distinguish space heating, hot water, cooling, pool circulation and other loads. State occupancy and seasonal changes. A floor area, bedroom count or annual bill alone cannot establish the right inverter, battery or heat-pump size. Check supply capacity, phases, starting loads and simultaneous operation before specifying equipment.
Design the heating and hot-water duty
Assess room heat losses, emitters, design flow temperature, hot-water draw-off, recovery time and siting/noise constraints. Check exact heat-pump duty at the design conditions and the existing distribution system. COP and seasonal test metrics are not guaranteed household bill reductions; compare performance and tariff assumptions explicitly.
Model generation at the property
Use a stated weather dataset, module plane, shading survey, temperature model and loss assumptions. Nameplate power is measured at defined test conditions, not a promise of continuous output. For example, twelve 500 Wp modules total 6 kWp at those conditions; that arithmetic alone says nothing about annual yield or the appropriate AC inverter size.
Size storage for a defined purpose
Separate usable energy in kWh from continuous and starting power in kW. Check reserve, efficiency, permitted discharge, temperature limits and exact inverter/firmware compatibility. A battery shifts energy with losses; it does not create free electricity. Compare a no-storage scenario before assigning any financial benefit to additional capacity.
Backup is a separate design
Ordinary grid-tied generation stops when the grid fails. Backup requires a supported operating mode, isolation from the grid, an approved earthing and protection arrangement, and defined circuits and loads. Check transfer behaviour and starting power against equipment requirements. A hybrid label or battery connection alone does not guarantee uninterrupted whole-home operation.
Compare financing with the full project cost
Obtain a written finance offer stating rate, APR, term, fees, total repayment, security and cancellation terms. Do not treat a promotional interest period as an interest-free project or presume energy savings cover repayments. Compare the same equipment and scope in cash and financed quotes, allowing for repairs and household cash flow.
Agree responsibilities and scheduling
Confirm who handles the survey, design, any community consent, municipal procedures, electrical registration and distributor or supplier submissions. Requirements depend on the property and installation. Equipment availability, safe access, enabling work and third-party decisions affect the schedule. Ask how faults, disruption and support requests will be handled; do not infer attendance hours from a website contact form.
Make financial assumptions explicit
Compare the actual installed quote with interval self-consumption, imports, exports, contracted prices and applicable credit limits. Include losses, fixed charges that remain, maintenance, replacement, finance and taxes. Treat incentives as conditional until their applicable requirements and, where required, award decisions are established. A simple cost divided by annual benefit is not a forecast or a guaranteed payback.
Documents and reference links
Check the current version and applicability. These links do not establish failure rates, LIT credentials or an outcome for your property.
Company contact
Ben HaydenPrepare for a useful assessment
Provide the location, objectives, existing models, plans or safely taken photos, and measured demand. Confirm scope, availability, assessment fees and responsibilities before booking.