Installed cost by system size
These are EECA's figures, not an installer's, and they include the panels, the inverter, installation and GST. Most published solar prices come from someone selling solar, and those tend to leave things out. If a quote lands well under this table, ask what is missing.
Quotes carry two different kW figures. The sizes below are panel capacity, the number that matches the panel counts.
The inverter is usually rated lower, and that gap is deliberate. Panels rarely reach their lab rating on a roof, so a larger array keeps the inverter working for more of the day, at the cost of a little output trimmed at midday. Fronius allows up to one and a half times an inverter's rating in panels.
| Item | Typical | Range | Unit |
|---|---|---|---|
|
Small system, around 3kW (about 7 panels)
Enough for a smaller household that is not drawing much during the day. |
$8,500 | $7,500 to $10,000 | installed |
|
Medium system, around 5kW (about 12 panels)
EECA match this size to an average three-person household with electric appliances and no EV. |
$11,500 | $10,000 to $13,500 | installed |
|
Large system, around 10kW (about 24 panels)
The size to look at if you have an EV, or expect one. Ask which inverter comes with it, because export limits cap the inverter, not the panels. |
$20,000 | $17,500 to $23,000 | installed |
|
Small system with a 5kWh battery
The battery EECA match to a system this size. |
$13,500 | $11,000 to $17,000 | installed |
|
Medium system with a 10kWh battery
The usual pairing, and the one most quotes will show you. |
$21,500 | $17,000 to $27,500 | installed |
|
Large system with a 20kWh battery
A serious amount of storage, and the price reflects it. |
$40,000 | $31,500 to $51,000 | installed |
|
Battery added to any system
The range EECA quote. Their own figures work out at about $1,000 for each kWh of storage, so a big battery lands above this. |
$5,000 to $15,000 | add-on |
Should you add a battery?
A battery is the biggest single add-on in any solar quote, and the one to think hardest about. If you are buying solar to save money, it usually works against you, and the arithmetic shows why.
A 5kW system typically costs $11,500 and takes about $1,200 a year off your bill. Add a 10kWh battery and the price nearly doubles, to $21,500. The saving cannot double with it, because a battery generates nothing. It only holds power you would otherwise have sold to the grid.
EECA put the gain from storage at 1 to 2 per cent of your return, and Consumer NZ reached the same conclusion, that a battery usually lengthens payback. Neither of them sells batteries.
None of this means don't buy one. Backup through an outage, an empty house all day, a plan that pays well at peak: those are real reasons. Just be clear which one is yours before you sign. If the reason is simply that you hate watching power go out to the grid for a few cents, read the next section first.
| Item | Typical | Range | Unit |
|---|---|---|---|
|
Battery storage, per kWh of capacity
Worked out from EECA's own numbers, which come to $1,000 a kWh at every size they list. |
$1,000 | $700 to $1,400 | per kWh |
|
A 5kWh battery, the smallest EECA price
Sized for a 3kW system. |
$5,000 | $3,500 to $7,000 | add-on |
|
A 10kWh battery
Sized for a 5kW system, which is the pairing you will see most often. |
$10,000 | $7,000 to $14,000 | add-on |
|
A 20kWh battery
Sized for a 10kW system. This runs past the $5,000 to $15,000 range EECA quote elsewhere, which their figures do not stretch to at this capacity. |
$20,000 | $14,000 to $28,000 | add-on |
The cheaper alternative to a battery
Solar pays best when you use the power yourself, because what a retailer pays you to export is less than what you pay to buy it back. A hot water cylinder is the cheapest way to close that gap, and you already own one.
James Le Page, EECA's lead technical adviser, calls an electric cylinder "kind of a budget battery". The reason it works is scale. EECA put water heating at about a third of a household's energy use, so shifting it into the middle of the day moves a large block of demand under your own roof.
A timer is the cost-effective option. It switches the cylinder on across the sunniest hours, whether or not the sun turns up. A smart switch costs more but does the job better: it watches what your panels are about to send to the grid and pushes that surplus into the cylinder instead. EECA name both as a low-cost way to lift what solar saves you.
Either is an electrician's job, and some installers fold one into the base price, so check whether yours is already in there before paying for it twice. Whichever you go with, get it priced next to any battery you are offered.
| Item | Typical | Range | Unit |
|---|---|---|---|
|
Hot water timer, supplied and installed
Many installers put a basic timer in with a new system at no extra charge, so ask before you pay for one. On its own it is a cheap unit plus an electrician's time. |
$300 | $150 to $600 | installed |
|
Smart switch or diverter, supplied and installed
Cheaper fitted alongside a new system, while the electrician is already on site, and dearer as a retrofit. A relay style switch sits at the bottom of this range, a full diverter at the top. |
$800 | $500 to $1,200 | installed |
What you get back
Where you live moves the saving less than people assume. EECA put Southland at about $1,047 a year and Marlborough at $1,467, with everywhere else in between. The 7 to 10 year payback holds as long as you use most of what you generate during the day.
We are not going to pretend this page can tell you your own payback. That depends on your roof's angle and direction, and on when your household actually uses power. EECA have built a calculator that models all three. Run your place through it, then use that number to check whatever an installer quotes you.
| Item | Typical | Range | Unit |
|---|---|---|---|
|
Annual saving on your power bill
Southland at the bottom, Marlborough at the top, on EECA's regional modelling. EECA put the national figure at $1,000 or more. Higher again if you can use more of what you make during the day. |
$1,200 | $1,047 to $1,467 | per year |
Estimate an installed solar system
What you pay to get it on the roof: panels, inverter and installation. EECA price a 7 panel system at $8,500, 12 panels at $11,500 and 24 panels at $20,000, roughly 0.4kW a panel, and the sizes in between are worked out proportionally from those three. What you'll save is a different question, and EECA answer that one better than we can.
Indicative range
Choose your options above
A rough range based on EECA's figures, not a quote, and not a prediction of what you will save. Get at least two written quotes. Ask each installer what self-consumption rate they used, because that one assumption can make a payback look years shorter than it is.
What moves the price
- Roof access. EECA list this as a direct cost factor. A single storey with room for a ladder is cheaper to work on than a steep two storey that needs scaffolding before anyone gets near the roof.
- System size and storage. The two biggest numbers in any quote, and they are separate decisions. Size the panels first, from what your household uses in daylight, then decide on storage.
- Roof direction and shade. Consumer NZ's advice is a north facing roof in full sun. Shade matters most in the middle of the day, when panels do most of their generating, so a tree across them at noon costs far more than one across them at 4pm.
- Roof condition. Panels last decades, so a roof near the end of its life should be replaced before they go on. Consumer NZ make the same point: nobody wants to lift a working array off after three years to fix the iron underneath.
- When you use power. Not just how much. Solar pays best when someone is home drawing power while the sun is up, and an EV or an electric hot water cylinder helps, because both can be set to run in the middle of the day.
- Your export limit. Since May 2026 the default is 10kW, replacing an older regime where some companies capped houses at 5kW, and a few offer a flexible limit instead. It caps what you push to the grid at any one moment, not how many panels you may fit.
- Panel warranty. Two numbers matter and quotes rarely set them side by side: the product warranty covers the panel itself failing, the performance warranty guarantees output years out. Two quotes for the same roof can match on one and differ sharply on the other, so ask for both.
Checking these figures yourself
Every price on this page comes from EECA, not from anyone who installs solar. For what you would actually save, run your own numbers through their calculator, which accounts for your roof and your household. We don't list buy-back rates: they change too often, and vary too much between retailers and plans, for a page like this to keep them honest.