Key takeaways
- Solar pays back through power you don't buy (about 40.6c a kWh, MBIE average, Feb 2026) far more than power you export (about 8c to 24c).
- Payback = installed price ÷ yearly saving. EECA: as little as 7 years; 10 to 12 in other situations.
- It suits homes with daytime use, electric appliances, a sound roof with space, and no roof or wiring renovations planned.
- Adding a battery stretches payback to 10 to 14 years (Solar Scout).
- EECA reports an average 1.34% sale price premium for homes with solar.
How to work out solar payback
Payback is the installed price divided by the yearly saving. The saving is the solar you use yourself multiplied by the price you'd otherwise pay, plus the solar you export multiplied by your buy-back rate.
| Step | Figure | Result |
|---|---|---|
| Generation | 6.6kW × 1,400 kWh per kW | 9,240 kWh |
| Used at home | 60% × 9,240 = 5,544 kWh × 40.6c | $2,251 |
| Exported | 3,696 kWh × 12c | $444 |
| Yearly saving | $2,694 | |
| Payback | $14,000 to $15,000 ÷ $2,694 | 5.2 to 5.6 years |
- Generation = system size (kW) × yearly output per kW for your region
- Saving = (kWh used at home × your price per kWh) + (kWh exported × your buy-back rate)
- Payback (years) = installed price ÷ saving
Sources: 1,400 kWh per kW is Solar Scout's NZ average (Auckland is 1,350 to 1,450); 40.6c is the MBIE average household price to February 2026; 60% self-use and a 12c buy-back are Solar Scout's worked example. This example is shorter than EECA's 7 years mainly because it uses the 2026 power price. It assumes your home uses at least 5,544 kWh a year, and makes no allowance for price changes or panel ageing. Put your own numbers in the payback calculator.
Why using your own solar matters more than exporting
Every kWh you use at home saves the full retail price, about 40.6c on the 2026 MBIE average. Every kWh you export earns a buy-back rate of roughly 8c to 24c, depending on your retailer. So the share of solar you use yourself decides your payback more than system size does.
Ways to use more of it: run the dishwasher, washing machine and hot water in the middle of the day, pre-heat or pre-cool with a heat pump, and charge an EV at home in daylight. Our buy-back rates guide lists retailer rates.
Who solar suits, and who it doesn't
EECA's checklist: solar suits homes with electric appliances and daytime power use, enough roof or ground space, a roof that won't need replacing within 10 years, no major renovations planned that affect the roof or wiring, and owners comfortable with the upfront cost and a multi-year payback.
- Suits: people home in the day (retirees, families with young kids, home offices), heat pump and EV households, north-facing roofs without much shade.
- Doesn't suit (yet): a roof due for replacement within 10 years, renters, a heavily shaded or south-facing roof, homes you plan to sell very soon, or very low power use.
If you're in the second group, a $149 solar report is cheaper than finding out after the install.
Is a battery worth it?
Usually not on payback alone. Solar Scout puts solar-plus-battery payback at 10 to 14 years, and adding a battery to existing solar at 15 years or more. A battery makes sense if you use a lot of power after dark, want backup during outages, or your buy-back rate is very low.
Does solar add value to a house?
EECA reports an average sale price premium of 1.34% for homes with solar. On a $900,000 house that's about $12,000, though a premium isn't guaranteed and depends on the system's age and condition.
Buy, lease or subscribe?
Buying outright or with a green loan keeps the system and its savings yours. Subscription models avoid the upfront cost but lock you into a long contract, and SolarZero's liquidation in December 2024 showed the risk of relying on the provider being around for 20 years or more.
Our buy versus lease guide covers what SolarZero customers learned.
Frequently asked questions
How long does solar take to pay for itself in NZ?
EECA says as little as 7 years, and 10 to 12 years in other situations. Solar Scout estimates 6 to 8 years for solar without a battery.
How long do solar panels last?
EECA describes a 25-year lifespan. Look for at least a 10-year panel product warranty (EECA).
Is solar worth it if I'm at work all day?
Less so, because you'll export more at 8c to 24c instead of saving about 40.6c. Moving hot water, laundry and EV charging into daylight helps. Try a lower self-use share in the calculator.
Is solar worth it in the South Island?
Output is lower in the south (Southland 1,100 to 1,250 kWh per kW a year; Canterbury 1,300 to 1,450) but the price you avoid is the same, so it can still pay. See Canterbury and Otago.
Will solar keep working in a power cut?
A standard grid-tied system shuts down in a power cut for the safety of line workers. You need a battery with backup capability to keep power on.
What's the best size system for payback?
The one that matches your daytime use. Oversizing adds panels whose output you mostly export at a low rate.
Sources
- EECA, Rooftop solar (checked Sept 2026)
- Solar Scout, How many solar panels do I need (updated 1 Apr 2026) (checked 1 Apr 2026)
- Canstar NZ citing MBIE Quarterly Survey of Domestic Electricity Prices to 15 Feb 2026 (checked Feb 2026)
- Solar Scout, Buy-back rates NZ (updated 31 Aug 2026) (checked 31 Aug 2026)
- Solar Scout, Solar battery storage NZ (updated 30 Aug 2026) (checked 30 Aug 2026)
- Solar Scout, Solar panel costs NZ (checked Sept 2026)
- Consumer NZ, SolarZero liquidation: what to do if you're a customer (6 Dec 2024) (checked Dec 2024)
General information, not financial advice. Prices and rates change; each figure shows where it came from and when it was checked.