How to Monitor Your Solar Production (App Guide)

To monitor your solar production in New Zealand, open your inverter manufacturer's app (most commonly Fronius SolarWeb, SolarEdge mySolarEdge, Sungrow iSolarCloud, GoodWe SEMS, or Enphase Enlighten) and check three numbers each week: daily kWh generated, peak kW output, and kWh exported to the grid. Compare these against your installer's commissioning baseline and the same month last year. If daily generation drops more than 15% versus your seasonal baseline (and the weather hasn't), something is up. That's the whole game: a baseline, a weekly glance, and a willingness to ring your installer when the numbers tell a story.

This guide is for any NZ homeowner who already has a solar system installed and wants to stop staring at the app wondering what the numbers actually mean. We'll walk through the major inverter apps used in Aotearoa, the metrics that matter (and the ones that don't), realistic seasonal baselines, and the red flags that should prompt a call to your installer. If your system is brand new, bookmark this and come back after your first full month of generation.

What Solar Monitoring Actually Means for NZ Homeowners

Every grid-tied solar system installed in New Zealand in the last decade ships with a monitoring portal, usually accessed via a smartphone app and a paired web dashboard. The inverter connects to your home Wi-Fi, uploads production data to the manufacturer's cloud every few minutes, and lets you see how much electricity your panels are making in real time.

Monitoring matters for three reasons. First, it's your early warning system: a failed panel, a tripped DC isolator, or a Wi-Fi dropout can silently cost you hundreds of dollars in lost generation before you notice. Second, it's your evidence locker if you ever need to make a warranty claim. Third, it's the only way to know whether your system is actually delivering what the installer promised on the day they handed over the keys.

The good news: you don't need to be a sparky to read an inverter app. You need ten minutes of orientation and a habit of checking weekly. That's it.

The Five Big Inverter Apps You'll Encounter in NZ

NZ residential solar is dominated by a handful of inverter brands, and each has its own app. Here's the lay of the land.

Fronius SolarWeb (Austrian brand, very common in NZ)

Fronius is the workhorse premium brand in Kiwi homes. SolarWeb gives you a clean current-power gauge, a daily energy bar chart, and a "Consumption" view if you've paid for the Fronius Smart Meter (most installers include this; if yours didn't, ask why). The "Energy Balance" screen is the one to live in: it shows generation, self-consumption, and grid export side by side.

SolarEdge mySolarEdge (per-panel monitoring)

SolarEdge systems use power optimisers on each panel, which means you get panel-level data, a genuinely useful feature for spotting shading or a single faulty module. Open the app, tap "Layout", and you'll see a heat map of your roof. One panel pumping out 280W while its neighbours all show 320W on a clear day is a story worth following up.

Sungrow iSolarCloud (the value workhorse)

Sungrow has become one of the most-installed inverter brands in NZ over the last three years. iSolarCloud is functional rather than beautiful: the "Plant" dashboard shows live power, today's energy, and total lifetime kWh. Hybrid Sungrow systems (with a battery) also show state of charge and battery flow direction.

GoodWe SEMS Portal

GoodWe inverters are popular in the mid-market and pair frequently with BYD batteries. SEMS Portal covers the basics adequately, though the alerts system is less polished than Fronius or SolarEdge. Check the "Energy Flow" screen for live data and the "Statistics" tab for daily/monthly comparisons.

Enphase Enlighten (micro-inverter premium)

Enphase uses a micro-inverter under every panel, so like SolarEdge you get per-panel data. Enlighten is arguably the prettiest of the lot, with excellent historical comparisons. If you have Enphase, the "Site" view is your home page.

Other apps you may run into: Huawei FusionSolar, SMA Sunny Portal, Solis Cloud, and Growatt ShinePhone. The metrics are the same across all of them; only the menu names change.

The Four Numbers That Matter (and the Ones That Don't)

Solar apps love to show you graphs. Most of them are noise. These are the four metrics worth caring about.

• Daily kWh generated. The headline number. This is what your panels made today, measured at the inverter. Compare to the same date last year, not last week.
• Peak kW output. The highest instantaneous power your system hit today. A 6 kW system in clear midday Auckland sun should peak around 4.5 to 5.5 kW (you rarely hit nameplate due to temperature derating and inverter clipping).
• Self-consumption ratio. The percentage of solar you used in your home versus what you exported. Higher is generally better for ROI, given NZ buy-back rates are lower than retail rates. Use our Solar System Cost & ROI Calculator to model this for your setup.
• kWh exported to the grid. What your retailer pays you for. Cross-check this monthly against your power bill.

What you can safely ignore on most days: the per-minute power graph, the CO2 saved counter (it's calculated, not measured), and the "trees planted equivalent" gamification stuff. They're fine; they're just not diagnostic.

Setting Your Baseline: What "Normal" Looks Like in NZ

You can't spot underperformance without knowing what good performance looks like for your system, on your roof, in your region. Here's how to set a baseline.

Use the EECA / NIWA "kWh per kW installed" rule of thumb

A well-installed, north-facing, unshaded solar system in NZ typically produces between 1,150 and 1,400 kWh per kW of installed capacity per year, depending on region. That's drawn from EECA's solar resource data and NIWA's irradiance records. So a 6 kW system should generate roughly 6,900 to 8,400 kWh per year.

Regional ballparks (annual kWh per kW installed):

• Northland / Auckland / Bay of Plenty: 1,300 to 1,400 kWh per kW
• Waikato / Taranaki / Hawke's Bay: 1,250 to 1,350 kWh per kW
• Wellington / Manawatū: 1,150 to 1,250 kWh per kW
• Nelson / Marlborough / Canterbury: 1,250 to 1,400 kWh per kW (Canterbury punches above its weight)
• Otago / Southland: 1,100 to 1,250 kWh per kW

Divide by 12 to get a monthly average, then remember the seasonal swing: a Wellington system might do 140 kWh in June and 900 kWh in December for the same 6 kW array. Don't panic in winter. Panic if last winter you got 200 kWh in June and this June you got 90.

Capture your "commissioning day" numbers

The single best thing you can do as a new solar owner: on the first sunny day after installation, take a screenshot of your app showing peak kW output at midday. That's your reference. If two years later, on a similar sunny day in the same season, your peak is 18% lower, that's a real signal.

Red Flags: When the Numbers Are Telling You Something

Most of the time, your system runs in the background and you don't think about it. But these patterns deserve a closer look.

1. Generation dropped sharply and the weather didn't

If yesterday you made 32 kWh and today (similar weather) you made 11 kWh, check the app for fault codes. Common causes: a tripped DC isolator on the roof (very common after a windstorm), a Wi-Fi dropout that stopped data uploads (the panels are fine, just the reporting), or a string fault.

2. One string is producing noticeably less than the other

Most NZ residential systems have two strings of panels feeding the inverter. If your app shows MPPT1 and MPPT2 (or "String A" and "String B") and one is consistently producing 25% less than the other on the same day, that's worth investigating. Could be shading, could be a dud panel, could be a connector issue.

3. Year-on-year generation is down more than 5%

Panel degradation in NZ is typically 0.4% to 0.55% per year for quality monocrystalline modules (per manufacturer datasheets and Consumer NZ's solar research). If you're down 8% year-on-year on a system that's only three years old, something other than normal degradation is at play. Dirty panels, a failing optimiser, or a partially failed string are the usual suspects.

4. The "Consumption" line is higher than it used to be

Not a solar fault, but worth watching. If your household consumption has crept up 20% without an obvious reason (new EV, new heat pump, new family member), there might be an efficiency leak somewhere worth chasing.

5. Export kWh is suspiciously low

If your app shows you're generating well but your retailer's bill shows almost zero export credit, check your inverter's grid-export settings. Some retailers (and some lines companies, like Vector in Auckland) cap export at 5 kW or apply export limiting. If your installer set export to "zero" by mistake during commissioning, you'd be self-consuming fine but sending nothing back. That happens more often than you'd think.

What This Means for You

If you're the ROI Pragmatist

Your monthly ritual: cross-check the kWh figure on your retailer bill against the export kWh in your inverter app. They should match within a few percent. If they don't, you may have a meter issue or a billing issue, and either way that's money you're owed. Also reconcile against the buy-back rate your retailer is paying; rates change, and our Ownership & Aftercare guide covers when to switch retailers.

If you're the Tech-Savvy Optimiser

Your inverter app is the front door, but if you've layered in a Home Energy Management System (HEMS), an EV charger like a Wallbox or Zappi, or a battery, you'll want to integrate everything via Home Assistant, EmonCMS, or the manufacturer's premium tier. Most NZ Fronius and SolarEdge installs offer Modbus TCP for local data. That's where the real optimisation lives, especially if you're on a dynamic tariff and want to time loads to your solar curve.

If you're the Eco-Conscious Family

The number to watch is self-consumption ratio. The more solar you use directly in the home (running the dishwasher at midday, charging devices during the day, pre-heating water with a timer), the more emissions you actually offset. Exported solar still helps the grid, but self-consumed solar replaces high-emission peak generation directly. Apps like SolarWeb and Enlighten show this percentage clearly.

What Installers Won't Always Tell You About Monitoring

A few honest truths the industry tends to gloss over.

Wi-Fi dropouts are the #1 cause of "missing data" panics. Inverters use 2.4 GHz Wi-Fi and sit in a metal box on an exterior wall. If your router is at the other end of a brick house, the inverter loses connection regularly. The panels keep generating; the cloud just doesn't know about it. A Wi-Fi extender near the inverter solves 90% of these cases.

"24/7 monitoring with alerts" doesn't always mean what you think. Many installers offer a "monitoring service" as part of their aftercare, but in practice it's a script that emails you if the inverter goes offline for 48 hours. It's not someone watching your dashboard. You are the first line of defence; the installer is the second.

Per-panel monitoring is genuinely better. If you're still in the quoting stage, the modest extra cost of SolarEdge or Enphase gear is often worth it specifically because of the diagnostic value over 25 years. String-inverter systems can hide a single underperforming panel for years.

Cloud platforms can disappear. If your inverter brand exits the NZ market (it has happened), your app may stop working. Always note down your inverter's local IP address and Modbus credentials at installation. That way you can read data locally even if the cloud goes dark.

A Simple Weekly Monitoring Routine

You don't need to obsess over the app. Here's a five-minute weekly routine that catches 95% of issues:

• Sunday evening: Open the app, look at the last 7 days of generation. Are any days obviously zero or near-zero that weren't stormy? If yes, dig in.
• Check peak kW: On your sunniest day of the week, did peak power look roughly normal for the season?
• Check fault codes: Most apps have a "Notifications" or "Events" tab. Any new red items? Note them.
• Monthly: Compare this month's total kWh to the same month last year. Big variance (more than 10%) without an obvious weather reason = phone call to installer.

If the app does flag something serious, our solar output troubleshooting guide walks through the first checks to do before ringing your installer, and our solar warranty claim guide covers what to do if it's a genuine fault.

Frequently Asked Questions

How often should I check my solar app?

Weekly is plenty for most homeowners. Daily checking is fine if you enjoy it but won't catch anything a weekly review wouldn't. Monthly is the absolute minimum, especially in winter when generation is low and a failure is easier to miss.

My inverter app shows no data, but my power bill is normal. Is my system broken?

Almost certainly not. The most common cause is a Wi-Fi dropout between the inverter and your router. The panels keep generating and feeding your home and the grid; the cloud just isn't getting updates. Try power-cycling the inverter's Wi-Fi or moving your router closer.

What's a reasonable peak kW for a 6 kW system in NZ?

On a clear summer midday with cool ambient temperature, expect 4.8 to 5.5 kW at the inverter. You won't see 6 kW because of inverter clipping, panel temperature derating (panels lose ~0.4% per °C above 25°C), and small system losses. In winter, peak might only reach 3.5 to 4 kW even on a clear day due to low sun angle.

How much does panel performance degrade each year?

Quality monocrystalline panels degrade about 0.4% to 0.55% per year per manufacturer datasheets, with most warrantied to retain 80-87% of original output at year 25. If you're seeing degradation significantly above 0.6% per year averaged over 3+ years, something is wrong.

My app shows export kWh but my retailer says zero. Who's right?

Your retailer pays on the reading from your smart meter (operated by your lines company), not your inverter. Small differences are normal because the two devices measure at slightly different points. Large differences (more than 10% gap consistently) point to either a meter configuration issue or an export-limiting setting on your inverter. Phone your installer first, then your retailer.

Do I need to pay for a premium monitoring subscription?

For most NZ homeowners, no. The free tiers of Fronius SolarWeb, SolarEdge mySolarEdge, Enphase Enlighten, Sungrow iSolarCloud, and GoodWe SEMS all show the metrics you need. Premium tiers are typically aimed at installers managing fleets, or tech enthusiasts who want API access and longer historical data retention.

What if my inverter brand goes out of business in NZ?

Generation continues normally; only the cloud reporting is at risk. Note your inverter's local IP and login credentials now (before you need them) so you can read data via the local web interface or via Modbus. Reputable installers should provide this info at handover; if yours didn't, ask.

Should I monitor battery state of charge separately?

If you have a battery (Tesla Powerwall, BYD HVS, Sungrow SBR, etc.), it should appear inside the same app as your inverter on most hybrid setups. Watch for batteries cycling unusually often (suggesting incorrect tariff or load setup), sitting at 100% during the day in summer (you have surplus you could time-shift), or failing to charge fully.

Can I monitor multiple homes from one account?

Yes, all major NZ-installed inverter platforms support multi-site accounts. Useful for rental property owners or anyone managing a parent's system.

Where to Go From Here

Monitoring is the simplest aftercare habit you can build, and it's the single best protection for your solar investment. Bookmark your inverter app, set a weekly reminder, and get familiar with what "normal" looks like across the seasons. When something does go wrong, you'll spot it in days rather than months.

From here, the natural next reads are our guide to cleaning and maintaining your panels (a surprisingly large lever on long-term output), our troubleshooting guide for when the numbers go sideways, and the full Ownership & Aftercare pillar for the bigger picture.