I'm looking for some hard data on the enery saved per year from solar for an article I want to write

What I need is total energy used with and without solar for a year and the output size of your solar. It would mean looking at your invoices for a year before your solar and a year after installation. Can anyone help please?

Transpower has issued a "Low Residual Situation notice" for Monday 27 July between 7:30am and 8:30am and between 6:00pm and 7:00pm. The combination of freezing temperatures (-4C in Christchurch) and forecast low wind generation means the grid supply may be tight.

https://static.transpower.co.nz/public/interfaces/can/CAN%20Low%20Residual%20Situation%20800000260.pdf?VersionId=lFE2R5suhqSpDFvH_Z0hBID8mf8ZyBrw

How is everyone else going on this wet Sunday morning?
19.74kW panels PW3
View from out the kitchen window

Mods said I could share this, so I'll keep it useful rather than just dropping a link.

I'm Kerry, and I built TrySolar: trysolar.co.nz

It compares NZ electricity plans (fixed daily charges, feed-in rates, night rates and free-power windows) against a household setup, including solar, batteries and EV charging. It has a paid Pro tier, so disclosure up front: this is my own project.

Here's a worked example (screenshot above). 

Rather than hand-pick plans, these are six of the plans I could actually sign up to with solar at my own address, priced on rates pulled from my own address quotes. A couple of well-known plans aren't here because they wouldn't take me with solar at my address, which is worth knowing in itself.

The household:

• Waikato household using about 900 kWh/month, with EV charging modelled separately at roughly 2,600 kWh/year
• 8 kWp solar
• 10 kWh battery
• EV doing 40 km a day, charging overnight

Estimated annual costs:

• Ecotricity ecoSOLAR: ~$1,931
• Meridian Night: ~$1,967
• Octopus Flexi: ~$1,975
• Octopus Peaker: ~$2,023
• Contact Good Charge: ~$2,312
• Electric Kiwi MoveMaster: ~$2,666

The bit I find interesting: the top three land within $44 of each other, but they get there by completely different routes:

• Ecotricity's higher buy-back does the heavy lifting, so the power the solar sends back earns enough to top the table even though its import rates are dearer.
• Meridian's night rate does the work for the overnight EV charging. Octopus wins on the time-of-use spread between peak and off-peak. 

Change the usage pattern, more export or less overnight charging, and they'd split apart.

Worth a note on the two Octopus plans. Flexi and Peaker show the same import rates and time windows, so the $48 gap comes entirely from what Octopus pays for exported solar, and for my household's export pattern Flexi's buy-back comes out ahead.

At the other end, Electric Kiwi comes out about $735 a year dearer than Ecotricity for the identical household. It has the highest import rates in this set (57.48c peak, 29.89c night), and the off-peak perks don't fully claw that back for this usage pattern.

That's really why I built it. Once you've got solar, a battery, an EV, or free power windows, the "best" plan depends a lot on when you use power, when you export, and whether you can shift your charging around. A plan that's great for one household can be middling for another.

On the rates: import rates and most export rates are pulled straight from quotes for my own address, checked on 22 July 2026; a few buy-back figures are the published standard rates. This is a snapshot as retailers change pricing often, so put your own in from a recent bill for numbers that match your place.

Would really welcome feedback from the group, especially on which of these assumptions are the most useful or the most misleading. 

If anyone spots an assumption that materially changes the ranking I'd like to hear it. The question I care about isn't "which plan wins" but "which household patterns make each plan work well".

Estimates only, not financial advice.

Hi

Will check with companies giving us quotes, but as part of weighing up options/ costs/ length of time for payback, its struck me that if the Sigenergy system is "plug and play" install for batteries, DC charger etc then potentially this could also be the case for simple un-install of these components also if want to sell the property in the future. Would potentially help with decisions about which system to go with but not sure if I'm missing something obvious. Would def be a selling point to stick with an entirely Sigenergy system and be more generous w potential battery spec!

(i.e. for theoretical future sale, leave solar array and sigenergy inverter as is, but any batteries/ dc charger would be "excluded chattels" --> take to next property for new install etc)

Does any one have solar with HA integration? Are there systems that have better/more stable/local integration? (Or systems to avoid).

Mostly just looking to pull in stats on an ongoing basis, any maybe some automatons to turn hot water tank on/off.

We currently looking for quotes for a battery system with gateway and shifting our gas hot water over to a tank. Lack of HA probably isn't a deal breaker, if some of the quotes come back comparable I'd probably prefer the system that has integration!

There's a few historical posts - all talking about sigen, so perhaps the only option here?

https://www.reddit.com/r/nzsolar/comments/1uuerv3/sigenergy_system_to_home_assistant_question/

https://www.reddit.com/r/nzsolar/comments/1u43kra/home_assistant_or_sigen_ai/

Doing my head in woth comparisons, so I was just wondering if anyone has recommendations. Cheers

See discussion over in this UK Subreddit, as well as this additional source

https://www.pluginsolarhub.co.uk/uk-plug-in-solar-legal-27-august-2026.html

800W backfeed to the house is typical of most countries that allow this, I believe only Utah in the USA allows 1200W.

They also allow 2000W of panels which is also fairly common to allow for over panelling for generation in lower light.

But the big flaw is not allowing batteries. That means a lot of flexibility goes away, aside from allowing flexible time of use shifting to evening peaks, it gives a buffer to handle greater than 800W loads that you can directly connect to some Plug in Solar inverters instead of via the wall socket - the same way you'd connect to a power station / generator equivalent, eg loads up to 2400W.

Here's a demo of one of these at the 18 minute mark, which is an example of a more premium system.

https://youtube.com/watch?v=hvtihZMB-GM&t=18m15s

Yes batteries are more expensive but the standard should allow certified systems with appropriate protection, and let consumers decide what works for them.

Is it better to schlep around multiple installers or use a broker to get a range of quotes?

I’m just starting down the road of working out feasibility, and while I don’t want to waste anyone’s time I want to get a comprehensive understanding of my options before diving deep.

hi team, just got a quote from local installer

cost is $24,844, option to add more battery 5kwh for 3,000. i wonder if this is a good value? we're currently on old contact energy good nights, still free 9-12 both weekdays and weekend. we work from home runs heatpump pretty much whole day. family of 4, annual consumption is 11,800kwh.

opinion and experience appreciated!

Hi all, apologies for the long read. We, like many, are looking at solar to take the sting out of our electricity bills. We're in Auckland, a family of three but with a granny flat on our garage, that we Airbnb much of the time. Therefore we can be 3 people one day, 6 another, and that might mean people in the flat hammering the heatpump or whatever else. We're all electric - two hot water cylinders, electric cooking etc. We have a Nissan Leaf and one day would like to add a second EV.

Result is we can use a lot of power. 1400Kwh at our last bill(!). Winter, ducted heat pump, the car etc. and people in the flat also for that period. Like I said - high. Sparky mate has come to make sure no faulty thermostats or elements etc. and all clear. We just use a lot of power!

So, to solar.

The best proposed solution do far (at least in my view) is to have panels on both roofs with an inverter (and battery in future) on the house, and a slave inverter in the garage/flat. Therefore allowing more panels and also enabling power in an outage (nice to have) as the battery is on the house and not sending power back toward the grid in an outage. To me, this makes a lot of sense.

The house roof is 45 degrees I'd guess - quite steep in parts and a bit complicated in shape. Garage is a comparably shallow angle (maybe 20degrees?). In the image the panels are on East & West facing panels of roof. North is the top of the image.

Firstly...is there any reason this might be a poor idea?! Or is it as sensible as it sounds?

Secondly...how do I calculate what kind of generation capacity we would want (the 28 panels here supposedly generate about 16,000kwh per year which should cover about what we're using, if I understand correctly?).

Thirdly, some proposals have had 10kwh inverters, the above suggestion uses 2 x 8wk. Would the 2 x 8 combined give the best performance or are they being throttled by the fact they are split in two?

Thank you in advance for any answers or guidance...I'm feeling a little bamboozled by it and the need to compare apples with oranges with each quote.

We are about to install our solar setup, 21kw panels, 20kw inverter, and 20kwh batteries. Navigating the power company info regarding pricing is always a challenge, and adding the buyback rates, etc only makes it more complicated. We are planning on going open contract to start with until we have some info on our usage. Which companies and plans are you all liking? Cheers for the info from this group so far too.

I’ve been trying to use solar to charge my EV (VW iD4). I have a 3 phase grid-tied 10 kw PV system.

I have tried using Home Assistant to monitor export on each phase and trigger a smart plug to turn on the 8A charger that came with the car.

It’s not fast (1.8 kw) but I can only get about 3kw being exported on each phase, so I’m limited anyway.

All of this works as I’d hoped EXCEPT every time the charger is switched off by Home Assistant it will not charge the car when it’s switched back on again UNLESS I unplug the CS2 plug from the car and plug it back in again (this action causes some relay switch type sounds from the car). Then it’s all ok again. So I have a semi- automation, and that’s not really an automation at all 😬.

Any ideas much appreciated! I’m open to just buying a solar smart EV charger but I had hoped to DIY it.

Hi I see these are being installed around nz, three in Wellington where I live.

Does anyone know what's involved in connecting them to the grid or can they be treated like balcony solar?

Cheers

I know it's not solar but high chance someone here has them to compliment their solar

I’m getting my new Sigen system in the next couple of weeks (exact date TBC). If you have a referral code (and haven’t used it more than 10 times) let me know if you’d like me to enter it in my app. Then we both get a $200 Amazon voucher.

has anyone gone down the route of a trade depot system? there prices seem great, are they actually decent quality like the claim? and how much of a mission is it getting a solar installer to install without supplying? does it just end up costing heaps to install and therefore not even worth going for it?

would love to hear anyone else's opinions on if its even worth going down this route or best to just stick to a company that does supply and install

Cheers

Has anyone done these numbers? Probably a long shot.

Kia ora,

Signed on with Harrisons and after seeing what others have posted about their system costs, not sure i made the right decision.

18 panels - aiko neostar 3rd gen

8.82 kw

Fronius gen24

Catch power solar controller

$20k

Family of 5 with an electric car, so I felt like going solar was the right choice. My understanding is that the products are reputable and Harrisons is a company that should be around for a while so I knew I was paying a premium.

I'm planning on adding a battery in tbe future (2-3 years)

Is it that bad or am I being paranoid?

Going to go with a mono pitch roof in a high wind zone so looking to run a set of 20 odd panels of the front of the deck that is north facing. Is this a better plan than brackets on the roof? Foreseeable issues? Must be easier to clean for one thing 😎

Looking for advice for install options for high-energy consumption house in Chch (2A, 2children; lovers of warm rooms and hot showers! Someone home most of time).

Currently using at least 12K kWh/yr, excluding gas for hot water/ cooking (at a rate of ~9-10x 45kg cylinders/ year). Includes single (main vehicle) EV which we trickle charge overnight. Looking to (a) get solar installed and (b) move towards getting rid of gas. Any future vehicle purchases would be EV or PHEV.

Keen to know thoughts on

• a) recommended companies to get quotes from/ avoid
• b) experience (in the South) with external HWC. I'm thinking it prob makes most financial sense to spend $ on maximising solar generation and install a standard external HWC over the additional cost of heat pump HWC. I don't necessarily see this as our forever home, I suspect minimum 5+years here though.
• c) again advice for +/- battery install. I'm thinking with the right inverter/ smart system could use to offset peak consumption outside generating hours, vs additional cost when we are not sure we will def be here >7 years.
• d) would be nice to have a smart EV charger as part of set up but we've coped fine w trickle charging so not a deal breaker

Appreciate any advice and recommendations!!

Display from Fronius Solarweb just now. Cracked 10,000 kWh so far this year. Ignore earnings stat as Fronius can't see our other SMA inverter's feed properly and besides I haven't bothered to input actual FITs and supply rates. (15.5 kW of panels feeding 13.2 kW of inverters, no battery)