Question 1

How are solar savings calculated?

Accepted Answer

Savings come from offsetting grid electricity usage with solar generation, valued at your retail rate or export tariff.

Question 2

How big should my system be?

Accepted Answer

Size (kW) depends on your annual kWh use, roof area, and solar resource; many aim to offset 60-100% of usage.

Question 3

What about efficiency losses?

Accepted Answer

Apply a performance ratio (e.g., 75-85%) to account for temperature, wiring, inverter, and dust losses.

Question 4

Do rates or incentives change results?

Accepted Answer

Yes—retail rates, export tariffs, and incentives like tax credits or grants affect payback and ROI.

Question 5

How long do panels last?

Accepted Answer

Panels often carry 25-year power warranties with ~0.5-0.8% annual degradation; inverters may need replacement sooner.

Solar Panel Savings Calculator — Solar ROI & Payback Calculator