The solar is on but the bill barely moved. What now?

A power bill that barely moves after solar power installation is common, and it has a short list of causes. The array may not be allowed to export yet. The house may use power after dark. Fixed daily charges may dominate a small bill. It may be winter. Or something is actually off. You can sort those with the bill, the inverter app, and the approval letter. You cannot sort them from the total dollars alone.

EECA's public examples, about $1,000 or more a year and about $1,246 for a typical 5 kW system in Auckland, are annual and assume you use a fair share of the generation in the house. They are not a promise that the next monthly invoice drops by a ninth of that number, and they are not a quote for your roof.

Read the bill in pieces

Find import kilowatt-hours, export kilowatt-hours, the buy-back credit, and the daily charge. A total that looks familiar can hide a lower import line and a daily charge that never moved. Solar does not remove lines charges.

If export is zero and the inverter shows energy produced, either the house used all of it, the export meter is not set up, or the system is barred from exporting. Check the approval. The first-month guide is the commissioning list: https://homesolarinstallation.co.nz/blog/first-month-after-solar-nz/

If the bill period is only partly after switch-on, do not annualise it. Wait for a full period, or do the arithmetic on the days that overlap.

Night use and the cylinder

Solar produces in daylight. A house that spikes at 7pm, with the cylinder on a night rate, will keep buying retail power for the hours that cost the most. The array's noon energy becomes export, paid at a lower rate, or it is clipped if the street has a cap.

Moving the cylinder into the day, where the supply allows it, changes the import line more reliably than switching retailer for a slightly higher buy-back. The cylinder guide and the buy-back guide are the two halves: https://homesolarinstallation.co.nz/blog/solar-hot-water-nz/ and https://homesolarinstallation.co.nz/blog/solar-buyback-rates-nz/

Check live rates before you switch. Powerswitch: https://www.powerswitch.org.nz/solar-rates

Season, shade and a real fault

A July bill compared with a January memory will look like failure on a healthy system. Use the monthly estimate. The winter guide sets the scale: https://homesolarinstallation.co.nz/blog/winter-solar-output-nz/

Shade from a low sun, a new tree, or a neighbour's scaffold can cut a string. If one face on the app is dead on a clear day, call the installer with the screenshot. If the whole array follows the weather smoothly, you are looking at climate and use, not a dead inverter.

An export limit produces a flat top on the power curve at noon when the house is empty. That is not a failed panel. Confirm the cap in the approval: https://homesolarinstallation.co.nz/blog/solar-export-limits-nz/

Size and the savings you were sold

A small array on a large bill will not transform the total. EECA's small band is about 3 kW and around $8,500 installed. Their medium band is about 5 kW and around $11,500. If your use is far above a typical household, a small system covers a thin slice. The size guide is how to test that: https://homesolarinstallation.co.nz/blog/solar-system-size-nz/

Ask the installer what annual self-consumption they assumed. If they assumed someone home all day and the house is empty, the quote was for a different life. Get a revised picture rather than another year of frustration.

A battery would move some noon energy into the evening. It costs extra, often about $5,000 to $15,000, and EECA says solar without storage usually pays back better. Buy it for a measured evening gap, not because one bill annoyed you. https://homesolarinstallation.co.nz/blog/solar-battery-storage-nz/

Retailer and meter problems

Export can be generated and still missing as a credit if the retailer plan does not include buy-back, or if the meter is not recording the channel. The inverter total and the bill export should be in the same range over a full read. When they are not, send both to the retailer and the installer.

A plan with a high daily charge and a weak night import rate can wipe out a modest export credit. Compare the whole plan. A higher buy-back on worse import rates can raise the bill.

Switching retailer is allowed on most solar accounts. Take the system size, inverter model and approval with you so the new account is set up as generation, not as an ordinary import-only ICP.

Also check the meter read dates against holidays and visitors. A fortnight of guests, a heat pump left on, or an EV charged every night will sit in the import line and can hide a perfectly healthy array. Split those kilowatt-hours out in your notes before you decide the panels failed.

A one-page diagnosis

Write the answers down. The pattern tells you who to call.

• Inverter kilowatt-hours for the bill period
• Bill import, bill export, daily charge, buy-back rate
• Approval date and whether export was permitted for that whole period
• When the house uses power, and when the cylinder runs
• Any noon flat-top that matches an export cap
• Weather: a grey month or a clear month that still produced nothing

These suburbs, your meter

A flat bill after solar panels are on is diagnosed from the meter and the app, wherever the house is, including Algies Bay, Arkles Bay, Army Bay, Big Omaha, Coatesville, Dairy Flat, Dome Forest, Dome Valley, Glorit, Gulf Harbour, Hatfields Beach, Helensville, Huapai, Kaukapakapa, Kawau Island, Kumeu, Leigh, Matakana, Muriwai, Omaha, Orewa, Puhoi, Riverhead, Snells Beach, South Head, Waimauku, Warkworth, Wellsford, Bayswater, Belmont, Campbells Bay, Castor Bay, Devonport, Forrest Hill, Hauraki, Milford, Narrow Neck, Stanley Point, Sunnynook and Takapuna. A bach at Omaha, Matakana, Leigh or on Kawau Island that is empty on weekdays will export more and self-consume less than a lived-in house in Forrest Hill, Sunnynook, Bayswater or Narrow Neck. Rural feeders around Glorit, Dome Valley and Wellsford can have tighter export conditions than a short North Shore street. None of that replaces reading your own import and export lines.

Home Solar Installation NZ can introduce a local partner if the system was never designed for how you use power, or if you are still at the quote stage. The form is free and there is no obligation. If the system is already up, start with the installer who holds the warranty, with the numbers above in the email. EECA's savings framing is here: https://www.eeca.govt.nz/for-homes/solar-for-homes/solar-costs-and-savings/