Do you need a battery to make solar worth it in New Zealand?

Quick answer: no, you don't need a battery for solar to be worth it. Panels pay their way on the power you use while the sun is up, so if your household is home during the day, or can shift the hot water and other appliances into the middle of the day, panels alone stack up. A battery is a second, separate decision that buys you morning and evening cover and a bit of resilience, and whether it pays comes down to when you use power and the price differences between your daytime export rate and your morning and evening peak purchase rates.

I get asked this quite a bit: "I looked at solar, but there's no point without a battery, and the battery pushed it out of reach." Two decisions have been welded into one, and the welding is what kills the project.

It is worth separating them out.

What are panels actually doing for you?

A panel does one thing: it makes electricity while the sun is on it. What that is worth to you depends entirely on where that electricity goes.

If you use it in the house at the moment it is generated, you have avoided buying a unit from your retailer. As at 15 November 2025, the national average residential rate was 39.3 cents a kilowatt hour including GST (according to MBIE). So every unit you self-consume is worth about 39 cents to you.

If you do not use it, it goes out to the network, and you get paid a buy-back rate instead. Buy-back rates vary by retailer and plan (typically 10-17 cents per kilowatt hour), i.e. they are noticeably less than the retail rate you pay. That gap is the whole game.

So panels are mostly a self-consumption investment. The more of your own sunshine you use yourself, the better they look.

What size system are people actually putting on?

EECA's figures for January 2026 show 74,904 home solar systems installed in New Zealand, totalling 419 MW. Divide one by the other and the average home system is about 5.6 kW. That is the arithmetic, not a figure EECA publishes directly, but it is a fair picture of what is going on roofs.

Solar is still a small slice of the national picture: EECA puts it at 1 to 2% of New Zealand's electricity in 2025, with 6 to 12% projected by 2035. Which is to say, most of the country's rooftop solar has not been installed yet.

A worked example: the MBIE model household

MBIE's model household uses 22 kWh a day, or 8,000 kWh a year, and pays for that at 39.3 cents per kWh. In round numbers, that is about $3,140 a year on electricity.

Now split that bill by time of day, because that is where the answer lives.

Household A: someone home in the daytime. E.g. retired, working from home, small kids, shift work. A good chunk of that 8,000 kWh is being used between roughly 9 am and 4 pm, which is exactly when the panels are producing. Most of what the roof makes gets used in the house at 39 cents of avoided cost. Panels alone do well here. A battery would add something, but it is chasing the smaller half of the bill and likely not worth the additional investment.

Household B: out all day, home at six. Everyone leaves at eight, comes back at half five, and then the oven, the shower, the heat pump and the telly all go at once. Almost everything the panels make in the middle of the day gets exported at the lower buy-back rate, and almost everything the house needs gets bought at the full retail or even higher peak rate. Panels still help, but they are helping much less than the brochure suggested.

Household B is where a battery genuinely changes the outcome. It takes the midday surplus that was going out at buy-back rates and holds it for the 6 pm rush, converting low-value exports into high-value self-consumption. Same panels, considerably more benefit with the battery.

And there is a cheaper move to try first: shift the load rather than store it. Hot water on a timer for the middle of the day, dishwasher on delay, washing machine at lunchtime, EV charging at the weekend when the sun is out. It costs much less than a battery and it moves Household B a decent way towards Household A. Do that before you price a battery, not after.

So why is everyone asking for a battery?

Because the conversation has moved, and quickly.

Of the 841 solar requests homeowners have sent to installers through Cogo, 437 asked for a battery alongside the panels (Cogo platform data, 31 July 2026). More than half.

Compare that with the housing stock as it stands. The Electricity Authority said in April 2026 that about 75,000 New Zealand households with solar can feed into their local networks, and more than 14,700 of those have a battery. Roughly one in five.

So the homes being planned right now look quite different from the homes already built. Part of that is battery prices coming down. Part of it is people having sat through enough outages, and enough winter evening bills, to want the evening covered rather than the afternoon.

Neither of which makes a battery right for your house. It just means you are not unusual for asking.

Is the paperwork about to get easier?

Yes, possibly quite a lot easier.

On 30 July 2026, the Government released a regulatory review of solar installation. The headline numbers for a household: getting a residential solar install approved currently costs about $640 and takes around three months, and the proposals would bring that to about $200 and six days. Lines company processing for a residential request would go from ten working days to the next working day. Officials put the overall benefit at $28 million to $50 million over ten years.

The review also recommends legalising plug-in solar, the small portable systems that are not currently allowed in New Zealand, aimed at renters and apartment dwellers who have had no way in at all until now.

None of it is law yet. Worth knowing about, but perhaps not worth waiting for.

How to decide, in about ten minutes

1. Look at your last bill and work out roughly what you use, and when. If you have a smart meter, your retailer can usually show you when you typically use your electricity.
2. Ask honestly whether the house is occupied in daylight, and what could be shifted into the middle of the day for free or low cost.
3. Price panels on their own first. Get the self-consumption case straight.
4. Then price the battery as an add-on, and judge it against the evening portion of your bill and how much you care about outages.
5. Get more than one quote. Ask about getting a 'battery ready' panels-only setup to hedge your bets and give you the option to more easily add a battery later.

FAQ

Does solar still work in a New Zealand winter?

Yes, just less of it. Output drops with shorter days and lower sun angle, so a system sized around your annual use will overshoot in summer and undershoot in winter. That is normal, and it is priced into any honest quote.

Will a battery keep my house running in a power cut?

Only if it is specified to. Plenty of installations shut down with the grid for safety reasons unless backup circuits are deliberately wired in. If outage resilience is why you want the battery, say so up front and get it in writing.

Is it cheaper to add a battery later, or do it all at once?

Doing it together saves you one lot of install labour and one lot of scaffolding, and lets the installer choose a hybrid inverter from the start. Adding later is entirely possible; just make sure the inverter you buy now can take a battery, or you will pay twice (for the inverter).

What about plug-in or balcony solar for renters?

Not legal in New Zealand at the moment. The Government's 30 July 2026 review recommends changing that, which would be the first real option for renters and apartment dwellers. Nothing to buy yet.

How much does solar cost in New Zealand?

It depends on system size, roof, and whether you add a battery, which is why we do not quote a single number. The average home system going in is about 5.6 kW (derived from EECA's January 2026 figures), and the fastest way to a realistic range for your place is to model it and then get quotes.

Run your own numbers

Nothing above beats doing it for your own house. The Cogo tool takes your home, your usage and shows what solar, a battery, or both would actually mean for your bills, then points you at vetted installers if you want to go further.

See what solar and a battery would do at your place

This article is general information only. It is not financial, energy or product advice. What you save depends on your home, your power plan and how you use energy, so get quotes from qualified installers or licensed dealers and seek independent advice for your own situation.