Buying Solar Panels in NZ: What You Need to Know

10 Things NZ Solar Buyers Wish They Had Known

• The meter change can take weeks and your system sits idle until it happens.
• Self-consumption percentage is the number that makes or breaks payback projections. Always ask what the installer used in their calculations. Normal is 30 to 50% without a battery. If the quote shows 100%, walk away.
• Two major NZ solar companies have collapsed in the last 18 months (SolarZero, Solar Group). Installer longevity matters.
• SEANZ certification is required for every bank green loan. No SEANZ, no 0% Westpac loan.
• Building consent is no longer needed for most residential installs since October 2025, saving about $1,060.
• Export limits (5kW) mean your excess is curtailed at the inverter. A hot water diverter uses it instead of wasting it.
• Hot water diversion pays back in about 3 years and costs $500 to $1,500. It is the best value add-on available.
• Winter production is about a third of summer. Do not expect year-round grid independence.
• The Consumer Guarantees Act protects you even if your installer goes bust. You can claim against the manufacturer or importer.
• Nobody regrets going bigger. The universal regret is "I wish I had put on more panels."

The Buying Timeline: Quote to Panels on Roof

Most people assume solar installation is a one-day thing. The physical install often is. But the full process, from first quote to a working, exporting system, typically takes about four weeks. Here is what that looks like.

Your system is fully installed but cannot export until the meter is changed. Contact your power company early to avoid weeks of idle waiting.

Common Mistakes NZ Buyers Make

The Self-Consumption Trick (and Other Quote Red Flags)

Consumer NZ flagged this in their investigation of the solar industry. Quote software allows installers to adjust the self-consumption percentage, which has an enormous effect on projected savings and payback period. Setting it to 100% (meaning you supposedly use every kWh you generate) makes the numbers look brilliant. But it is not realistic for any household that leaves the house during the day.

Realistic self-consumption rates:

• Without a battery: 30 to 50% (higher if someone is home during the day)
• With a hot water diverter: 45 to 65%
• With a battery: 60 to 80%
• With a battery and hot water diverter: 75 to 90%

If a quote shows 100% self-consumption without a battery, the installer is either incompetent or dishonest. Either way, get a different quote.

Always ask: "What self-consumption percentage did you use in this projection?" If the answer is above 50% and there is no battery in the quote, something is wrong.

Other red flags to watch for:

• "Sign today" pressure. Genuine installers give you time to compare.
• No site visit. A quote without physically seeing your roof is not worth the paper it is on.
• Vague brand names. "Premium tier-1 panels" without specifying the actual brand and model.
• No itemisation. Just a single total price with no breakdown of panels, inverter, mounting, and labour.
• Missing GST. Always confirm the price is GST-inclusive.
• Price dropping dramatically when you hesitate. The original price was inflated.
• Not SEANZ certified. Mandatory for bank green loans and a basic quality indicator.

What Happens if Your Installer Goes Bust?

This is not a hypothetical question. Two major NZ solar companies have gone into liquidation in the last 18 months.

How to protect yourself:

• Own your panels outright. Avoid lease and power purchase agreements where you do not own the equipment. SolarZero's model left customers trapped.
• Check SEANZ membership. Not a guarantee of survival, but adds accountability.
• Verify the panel brand has NZ-based warranty support. Ask who the local distributor or importer is.
• Avoid grey imports. If panels were sourced outside authorised channels, the manufacturer may refuse to honour the warranty.
• Keep all documentation. Certificate of Compliance, Record of Inspection, warranty cards, invoices, and system design specs.
• Know your Consumer Guarantees Act rights. You can claim against the manufacturer or importer, not just the installer. This is law, and it sits on top of any express warranty.

A 25-year panel warranty is worthless if your installer folds in 3 years. Check who actually backs the warranty: the manufacturer, the importer, or just the installer.

SEANZ, Green Loans, and Why They're Connected

Every major NZ bank offering a green or sustainable energy loan requires your installer to be a SEANZ (Sustainable Energy Association of New Zealand) member. This is non-negotiable. If your installer is not SEANZ certified, you cannot access any of these rates.

The Westpac deal is the standout: genuinely 0% interest for five years on up to $50,000. The catch is you must pay it off within five years or a default rate of 5% kicks in. Most of the other banks require an existing mortgage with them, as the green loan is typically structured as a mortgage top-up.

New Zealanders have borrowed over $1 billion in green loans for heat pumps, solar, EVs, and home energy improvements. The infrastructure for financing solar is solid. You just need a SEANZ installer to access it.

Building Consent: What Changed in October 2025

Good news. Changes to Schedule 1 of the Building Act on 23 October 2025 mean that most residential solar installations no longer need building consent. This saves homeowners about $1,060 in consent fees and eliminates processing delays.

• Under 40m2 total array area, standard wind zone: No consent needed. This covers the vast majority of residential installs (a typical 6.6kW system with 15 panels is about 30m2).
• Over 40m2 or high wind zone: No consent needed, but the structural fixings must be designed or reviewed by a Chartered Professional Engineer (CPEng).
• Solar panels used as roof cladding (replacing tiles/iron, not sitting on top): Still needs consent.
• Heritage or design-sensitive zones: May need resource consent from your local council.

One related change to be aware of: from 1 September 2026, any grid-connected solar must be installed by an electrician holding a Mains Parallel Generation Systems endorsement. This was originally set for September 2025 but was extended by 12 months to allow electricians time to complete the required training. Make sure your installer is qualified.

The Meter Change Bottleneck

This catches almost every new solar owner off guard. Your system is installed, inspected, and ready to go. But it cannot export power to the grid until your power company swaps your meter to an import/export smart meter. The cost is about $127, and it is arranged by your power company (not your installer). The problem is timing: it is entirely out of your installer's control.

Some homeowners report same-week meter changes. Others wait several weeks, particularly during summer when installations peak. During this time, your system can power your house in real time but cannot export anything. Any excess generation is simply curtailed.

What to do: Contact your power company the moment you sign the installation contract. Tell them the expected installation date and ask them to schedule the meter change for as close to that date as possible. If you already have a smart meter, it may only need reconfiguring rather than physical replacement, which is faster.

Hot Water Diversion: The Best Add-On Nobody Mentions

A solar diverter takes excess energy that would otherwise be exported at your buy-back rate (typically 8 to 12c/kWh) and redirects it to heat your hot water cylinder. Since retail electricity costs 30c+ per kWh, every diverted kWh saves you 18 to 22c more than exporting it. Contact Energy ran a trial and found that up to 38% of solar electricity generated could be used to heat the cylinder.

• Cost: $500 to $1,500 installed
• Payback: About 3 years
• Works with: Standard electric hot water cylinders only
• Does NOT work with: Heat pump hot water systems (they need steady power, not the variable trickle a diverter provides)
• Popular NZ brands: SunStash, Green Catch

A hot water diverter is essentially a cheap thermal battery. For $500 to $1,500 you get most of the benefit of a $14,000 battery system, at least for hot water. If you are installing solar and you have a standard electric hot water cylinder, this should be at the top of your add-on list.

A $1,000 hot water diverter pays for itself in about 3 years. A $14,000 battery takes 10 to 15 years. For pure economics, the diverter wins by a wide margin.

String vs Micro vs Hybrid: Choosing Your Inverter

The inverter converts your panels' DC electricity into the AC power your home uses. There are three main types, and the right choice depends on your roof and your plans.

A common NZ sizing note: with most EDBs limiting export to 5kW, it is standard practice to oversize your panels relative to your inverter. A 6.6kW panel array on a 5kW inverter is perfectly normal. You generate more during morning and evening hours when the sun is low, and only clip during the midday peak when you would hit the export limit anyway.

Insurance: What You Need to Tell Your Insurer

You must notify your insurer when you install solar panels. Solar panels attached to your home are covered under your home insurance policy, but only if your sum insured reflects the full value of your property including the panels. If you do not update it, you could be underinsured.

• Update your sum insured. Add the full installed cost of the system to your declared home value.
• Premium increases are usually modest. Solar panels add value to your property, which bumps the sum insured, but the premium increase is typically small.
• Insurance covers event damage (storms, fire, falling trees), not equipment failure. Equipment failure is covered by manufacturer and installer warranties.

The Warranty Landscape (and What's Actually Enforceable)

There are four separate warranties covering your solar system. Understanding which one does what saves a lot of confusion when something goes wrong.

The workmanship warranty is the most vulnerable because it dies with the installer. The panel and inverter warranties are backed by the manufacturer, which survives the installer going bust. Under New Zealand's Consumer Guarantees Act, businesses cannot limit their obligations to just the terms of a written warranty. Your CGA rights sit on top of any express warranty. If your installer folds, you can make a claim against the manufacturer or the NZ importer/distributor.

Watch out for grey imports. If panels were imported outside authorised channels, the manufacturer may refuse to honour the warranty. Always ask your installer: "Who is the authorised NZ distributor for these panels?"

What to Expect Month by Month

Your first year with solar will feel like a rollercoaster. Understanding the seasonal pattern stops the mid-winter panic.

• December to February: Peak production. Your system will generate more than you use on most days. This is when solar feels amazing.
• March to May: Production drops noticeably. You will start drawing more from the grid, especially in the evenings.
• June to July: The low point. A 6kW system might only produce 8 to 12 kWh per day, compared to 25 to 30 in summer. This is normal.
• August: Recovery begins. Production picks up and the days get noticeably longer.
• September to November: Ramping back to full production. By November you are back to generating more than you use.

On average, summer generation is about 47% higher than winter. The rough rule: winter production is about a third of summer. If you are in Southland, it can drop to as low as 2 peak sun hours per day in June. Further north, you will fare better, but the seasonal swing is real everywhere in New Zealand.

This is why solar is sized for annual production against annual consumption. Summer surplus compensates for the winter deficit. Think of it like a savings account: you deposit more in summer and draw down in winter.

What to Do Next

You now know more about buying solar in NZ than 95% of people who sign a contract. Here is how to put that knowledge to work.

Frequently Asked Questions