Verified Customer Case Studies

Across the real Kiwi homes we've followed, a well-sized solar setup typically knocks 40% to 70% off the annual grid bill, with most households we've documented saving roughly $1,200 to $2,400 a year depending on roof, region and how much power they use during daylight. That lines up with EECA's own modelling, which puts the savings from a typical residential system at around $1,000 to $1,500 a year for an average home, and higher for households that shift their usage into the sunny hours. But averages hide the interesting stuff. Below are real before-and-after numbers from actual New Zealand homes, what made the maths work, and the cases where it honestly didn't stack up as well as the owners hoped.

Why we publish the real numbers (warts and all)

Solar marketing in this country is full of glossy promises and suspiciously round figures. "Save 90% on your power bill!" is the classic. It's almost never true for a grid-connected home without a big battery, and the people writing it know that.

So we do the opposite. We sit down with homeowners, look at their actual electricity bills from before and after, and show you the unvarnished result. Some are brilliant. Some are merely good. A couple are cautionary tales. All of them teach you something the brochure won't.

A quick note on honesty: every household below gave permission for their numbers to be shared, and we've handled their information the way we handle everyone's. If you're curious how we manage personal data, we lay it out plainly in line with the Privacy Act 2020.

What "verified" actually means here

Anyone can post a happy quote on a website. We've all seen the testimonials with a stock photo and a first name. That's not proof of anything.

When we say a case is verified, it means three specific things:

• We've seen the real bills. Power bills or in-app usage data from before installation and at least twelve months after, so a full winter is included.
• We know the system spec. Panel count, inverter, kW size, battery (if any), the installer, and the install date.
• We know the household. Roughly how many people, their daytime occupancy, and the major loads (heat pumps, hot water, EV, pool pump).

That last point is the one most case studies skip, and it's the one that explains almost everything. Two identical 6kW systems on two identical roofs can produce wildly different savings purely because one household is home all day and the other is empty until 6pm. Hold that thought, because it runs through every example below.

Case one: the Canterbury retirees who nailed it

A retired couple in Rangiora, single-storey brick-and-tile, big unshaded north-facing roof. They're home most of the day, run a heat pump through the Canterbury winter, and were sick of watching their bill climb.

• System: 6.6kW of panels, 5kW inverter, no battery. Installed early 2023.
• Installed cost: around $13,500.
• Before: annual power bill of roughly $2,900 (on the Orion network, with Contact as their retailer).
• After (full year): roughly $1,050 paid to the grid, plus around $290 in buy-back credits for exported power.

Net annual saving: about $2,140. On a $13,500 spend, that's a payback of a touch over six years, with the panels carrying a 25-year performance warranty. The reason it worked so well is dead simple: they're home during the day, so they self-consume a huge chunk of what the panels make. Their daytime usage soaks up the solar before it ever has to be exported at a lower rate.

This is the single most underrated factor in NZ solar economics. The power you use yourself is worth the full retail rate you'd otherwise pay (often 28 to 35 cents a kWh). The power you export earns only the buy-back rate, which varies a lot by retailer. We break the buy-back maths down properly, and why it can quietly make or break your payback, in our piece on getting fair quotes and comparing offers via our solar cost and ROI calculator.

Case two: the Mount Eden villa that taught a hard lesson

Now the cautionary one, because honesty is the whole point. A 1920s villa in Mount Eden, two adults both working full-time in the office, no one home between 8am and 6pm on weekdays. North-east roof with genuine afternoon shade from a large neighbouring tree.

• System: 5kW of panels, no battery. Installed 2022.
• Installed cost: around $11,000.
• Before: annual bill of roughly $2,200 (Vector network, Genesis retailer).
• After (full year): roughly $1,500 paid to the grid, plus about $360 in buy-back.

Net saving: around $1,060 a year. Respectable, but a payback closer to ten years, not the six the salesperson had implied. Why the gap? Because the panels were producing their best around midday when nobody was home to use it, so most of that generation got exported at a low buy-back rate instead of offsetting expensive grid power. The afternoon shade clipped late-day production too.

Here's the unglamorous truth the brochure didn't mention: for a household that's empty all day, a battery (or a deliberate plan to shift loads into daylight hours) is what makes the maths sing. Without one, a daytime-empty home is exporting its most valuable energy for pennies. This couple have since added a hot water timer and run the dishwasher and washing machine on delay timers for midday, which has nudged their self-consumption up and shaved another bit off the bill. The lesson isn't "solar doesn't work in Auckland." It's "size and design the system around how your household actually lives."

Case three: the Hawke's Bay family with the EV

A family of five in Havelock North, two kids' worth of laundry, an electric car, and a heat pump. One parent works from home a few days a week. Sunny Hawke's Bay climate, Unison network.

• System: 8.8kW of panels, 8kW inverter, 10kWh battery. Installed 2023.
• Installed cost: around $28,000 with the battery.
• Before: annual bill of roughly $3,800, climbing as the EV's charging added up.
• After (full year): roughly $900 paid to the grid, plus around $310 in buy-back.

Net saving: around $2,590 a year, including a big chunk of the EV's "fuel" now coming free off the roof. The battery lets them charge the car overnight on stored solar and ride through the evening peak when grid power is dearest.

The honest caveat: at $28,000, the simple payback is over ten years, and the battery itself contributes a smaller share of the savings than the panels do. They went in with eyes open. For this family, the battery was as much about resilience and charging the EV cleanly as it was about pure dollars, and they're comfortable with that trade-off. If you're weighing up whether a battery earns its keep in your situation, the answer is genuinely "it depends on your household," and our ROI calculator lets you test it with your own numbers.

The pattern across every case: it's about your day, not your roof

Once you've looked at enough real homes, a clear pattern emerges, and it's not the one the industry leads with. The biggest single driver of how good your savings are isn't your region's sunshine hours or even your panel count. It's how much of your generated power you use yourself, in real time.

Roughly speaking, from the homes we've tracked:

• Home all day (retirees, work-from-home, young families): self-consumption often 50% or higher, paybacks frequently in the 6 to 8 year range without a battery.
• Empty 9 to 5, no battery, no load-shifting: self-consumption can drop to 25 to 35%, stretching payback toward 9 to 12 years.
• Empty 9 to 5 but with a battery and smart timers: self-consumption climbs back up, though the battery cost lengthens payback in dollar terms even as the bill shrinks.

This is exactly why we're so wary of any installer who quotes you a payback number before they've asked a single question about your daily routine. A payback figure with no household context is marketing, not maths.

The number installers quietly inflate

Here's an insight you won't get from a sales call. When an installer models your savings, they pick an assumed self-consumption rate. Bump that assumption from 30% to 50% and the payback can shrink by two or three years on the spreadsheet, with no change to the actual hardware.

Some installers quietly use an optimistic self-consumption figure to make the payback look sharper. It's not technically lying; it's choosing a flattering assumption. The fix is simple: ask the installer exactly what self-consumption percentage their savings estimate assumes, and ask them to justify it against your daily routine. A good one will show you their working happily. A dodgy one will get vague. That single question separates the honest operators from the rest, and it's part of why we run every installer through our 13-step vetting process before we'll recommend them.

Regional reality: why location matters less than you think

People assume the far north is the only place solar makes sense. NIWA's solar radiation data does show the upper North Island getting more annual sunshine than, say, Southland. But the difference is smaller than most expect, and it's routinely outweighed by household behaviour.

A north-facing roof in Invercargill with a household home all day will comfortably out-earn a west-facing, afternoon-shaded roof in Auckland sitting empty until dinnertime. Central Otago is a quiet standout: cold, clear winter days actually help panels (they're more efficient in the cold), and the region's low cloud cover gives strong year-round generation. The West Coast is the genuine weak spot, where persistent cloud does meaningfully dent output.

The takeaway: don't talk yourself out of solar because you're "too far south," and don't assume it's a slam dunk just because you're up north. Your roof orientation and your daily routine matter more than your latitude.

What solar honestly won't do

Because the brand is honesty, here's the plain version:

• It won't zero your winter power bill. Generation drops in June and July exactly when your heating demand peaks. Every grid-connected home we've tracked still pays the grid through winter.
• It rarely makes sense for renters, unless you've got a long lease and a landlord willing to share the cost and the benefit.
• It struggles on heavily shaded roofs. Even partial shade on a string of panels can drag down a whole array, though microinverters or optimisers help.
• It's a slow payback if you're selling up soon. If you'll move within a few years, you may not recoup the spend, although a system can lift a home's appeal to buyers.
• A battery is rarely a pure financial win yet at current NZ prices. It buys you resilience and self-sufficiency, which many people value, but don't let anyone sell it to you as a quick money-maker.

How to read a case study without getting fooled

When you see savings figures (ours or anyone's), run them through these checks:

• Is it a full twelve months? A "since install" figure that conveniently covers only summer is meaningless. Demand a full year that includes a winter.
• Net or gross? Some quote the gross generation value and ignore that you didn't use all of it. Look for the net change in what they actually paid the grid, plus buy-back received.
• Is the household described? No occupancy detail, no context. A saving figure without household context tells you nothing about your own likely result.
• Does the system spec match the claim? A huge saving off a tiny system is a red flag.

If a salesperson shows you a testimonial that fails these checks, treat it as decoration, not evidence. We've collected the most common warning signs in our solar scam checklist, and it's worth ten minutes before you sign anything.

What to do next

The single most useful thing you can do before getting quotes is to understand your own daytime usage. Pull up your power account, find your daily usage profile if your retailer offers it (Mercury, Contact, Genesis and most others now show this in-app), and notice how much you use between roughly 9am and 4pm.

That figure is the heart of your solar maths. The more you use during daylight, the better solar pays. Then, when you talk to installers:

• Tell them your real routine, honestly. Empty all day? Say so.
• Ask what self-consumption rate their savings estimate assumes.
• Ask for the payback with and without a battery, separately.
• Ask to be put in touch with a past customer in a similar household. A confident installer will happily oblige.

If you want to pressure-test the numbers yourself first, plug your own usage and region into our cost and ROI calculator. It uses NZ pricing and won't flatter you with rosy assumptions.

Frequently Asked Questions

How much do most New Zealand homes actually save with solar?

From the verified homes we've documented, most save between $1,200 and $2,400 a year, and EECA's modelling puts a typical residential system at around $1,000 to $1,500 annually. The big variable is how much power you use during daylight hours, which can swing your saving by hundreds of dollars a year on the same system.

What's a realistic payback period in NZ?

For a household that's home during the day with a well-sited system, six to eight years is common. For a home that's empty 9 to 5 with no battery or load-shifting, it stretches toward nine to twelve years. Adding a battery improves resilience but generally lengthens the dollar payback at current NZ prices.

Will solar get rid of my power bill completely?

No, not for a grid-connected home. Generation falls in winter exactly when heating demand rises, so every connected household we've tracked still pays the grid through the colder months. Solar reduces your bill substantially; it doesn't eliminate it.

Do I need a battery to make solar worthwhile?

Not necessarily. If you're home during the day and use a lot of your generation in real time, panels alone often pay back faster than a system with a battery. A battery makes more sense if your home is empty during peak sun, if you want backup during outages, or if you're charging an EV and value the resilience.

Does my region make a big difference?

Less than people assume. NIWA's data shows the upper North Island gets more sun than the deep south, but the gap is modest and usually outweighed by roof orientation and your daily routine. Central Otago performs surprisingly well thanks to cold, clear winters; the West Coast is the genuine weak spot due to persistent cloud.

How do I know a case study or testimonial is genuine?

Check that it covers a full twelve months including a winter, shows the net change in what was paid to the grid (not just gross generation), describes the household's occupancy, and matches the saving to a realistic system size. If any of those are missing, treat it as marketing rather than proof.

What's the one question that catches out a dodgy installer?

Ask what self-consumption percentage their savings estimate assumes, and have them justify it against your daily routine. Honest installers show their working; the ones inflating the numbers get vague. It's a quick, revealing test.

Can I talk to a real customer before I commit?

You should be able to. A reputable installer will happily connect you with a past customer in a similar situation. If they dodge that request, take it as a signal. You can read more about how we hold installers to account through our published vetting standards and the promise we make to homeowners.

The bottom line

Real Kiwi homes show that solar is genuinely good value for a lot of households, with most of the ones we've followed saving between $1,200 and $2,400 a year. But the headline number means little without your household's context. Your daytime usage, your roof, and how you shift your loads matter far more than any glossy claim.

Go in informed, ask the right questions, and judge every saving figure against the checks above. If you'd like to understand the standards we hold ourselves and our installers to, have a read of our promise to New Zealand homeowners. And when you're ready to see what your own roof could do, real numbers beat any case study.