Are solar panels worth it?

For a homeowner with a suitable, unshaded roof, solar is one of the best large upgrades for reducing power bills. The most valuable electricity is usually the solar you use in your own home, because it replaces power imported from the grid. Run hot water, the dishwasher, washing machine and dryer while the panels are generating whenever you can.

Buy the largest well-priced array that suits your roof and budget—but check the approved export limit first. New Zealand’s default export limit for straightforward residential connections is now 10 kW, although a network can approve a lower limit where local constraints require it. The export limit is not necessarily the same as the panel capacity: EECA says around 20% more panel capacity than inverter capacity often provides good value, so an installer might recommend 12 kWp of panels with a 10 kW inverter.

Think of solar as a long-term investment in lower household expenses. The installation price is your initial investment, the annual reduction in your power bill is the return, and the payback period is the point where those accumulated savings recover the purchase price. EECA says well-maintained panels typically last 25–30 years and lose around 0.5% of output each year. A sensibly priced system that pays for itself well inside that life can keep producing savings for many more years, although the actual return still depends on sunshine, household use, electricity prices, maintenance and finance costs.

Low-cost mortgage top-ups can make the upfront cost easier to manage. Several major New Zealand banks currently include solar in discounted lending: Westpac advertises up to $50,000 interest-free for five years, while ASB and BNZ advertise eligible top-ups of up to $80,000 at 1% for three years. These offers have lending criteria and can change, so include repayments and any interest after the discounted period when judging the return.