A sizing guide for Mid North Coast NSW homes
What Size Solar System Do I Need?
Your power bill already has the answer in it. Take your average daily usage, work out how much of it happens while the sun is up, and divide by what a kilowatt of panels actually makes here between Coffs Harbour and Forster — about 4kWh a day across the year. This guide walks through that maths with real Mid North Coast numbers, so you can check any quote you’re handed.
The short answer
Most Mid North Coast households land somewhere between 6.6kW and 13kW of panels. A couple who are out during the day usually suits 6.6kW. A family of four using 18–25kWh a day, or anyone planning a battery or an EV, is usually better off at 10kW of inverter with around 13kW of panels on a single-phase connection.
The quick formula: daily kWh you want solar to cover ÷ 4 = kW of panels. Then check it against June, when the same panels make about a quarter less.
How to Size Your Solar System in Four Steps
Grab your last power bill. You'll need it for step one.
1
Find your daily usage
Look for the total kWh on your bill and divide it by the number of days in the billing period. A quarterly bill showing 1,460kWh over 91 days is 16kWh a day. If you can, check a winter bill and a summer bill — plenty of homes around Port Macquarie and Taree use 30–40% more in the months they’re running reverse-cycle heating or cooling.
Your retailer’s app or the Essential Energy data request will give you half-hourly data, which is even better. That’s what we use when we design a system.
2
Work out when you use it
Solar only saves you money directly when you use it as it’s made. A household where everyone is at work or school until 4pm might only use 25–35% of its power in daylight. A retired couple at home, or someone working from home, can be closer to 50–60%.
This split matters more than the total. Power you use from your panels is worth whatever your retailer charges per kWh; power you export earns a feed-in tariff of just a few cents.
3
Divide by local output
On a north-facing roof with little shade, each kilowatt of panels on the Mid North Coast produces roughly 4kWh a day averaged over the year. That drops to about 3kWh in June and climbs past 5kWh on clear summer days.
So a 6.6kW system makes around 26kWh on an average day and about 20kWh in the middle of winter. Always size against winter if you want the system to still pull its weight in July.
4
Check the roof and the network
The number you land on then has to fit three real-world limits: how much usable roof you have, what inverter size your phase connection allows, and how much Essential Energy will let you export. These are covered further down the page.
Most of the time the roof and the network, not your bill, are what set the final size. That’s why a site visit beats any online calculator.
Solar System Size by Household
A starting point, not a quote. Your bill and roof will move these numbers.
| Household | Typical daily use | Suggested panels | Average daily output* |
|---|---|---|---|
| 1–2 people, out most weekdays | 8–12kWh | 5–6.6kW | 20–26kWh |
| 2–3 people, someone home during the day | 12–18kWh | 6.6–8kW | 26–32kWh |
| Family of 4–5, air conditioning | 18–25kWh | 8–10kW (13kW with a battery) | 32–52kWh |
| Large home, pool, ducted air or an EV | 25–40kWh | 13kW single phase, or more on three phase | 52kWh+ |
*Annual average for a north-facing, unshaded Mid North Coast roof at roughly 4kWh per kW per day. East–west roofs typically produce 10–15% less over a year. Expect around 25% less than these figures in June and July.
Three Real Sizing Examples From Around the Region
Same method, three very different answers.
Family of four, Port Macquarie
16kWh a day · both parents work · kids home after 3pm
Only about 5–6kWh of their usage happens in daylight. The rest is cooking, washing, TV and the split systems after dark.
What we’d suggest: 6.6kW of panels on a 5kW inverter makes around 20kWh even on a June day. That covers their daytime use with enough left over to fill a 13–16kWh battery most of the year. Without a battery, a bigger array would mostly be exported for cents.
Retired couple on acreage, near Kempsey
22kWh a day · home all day · bore pump and two split systems
Around 60% of their power is used in daylight, so almost everything the panels make gets used on site — the best position to be in.
What we’d suggest: around 10kW of panels on an 8kW inverter, with the pump and hot water on timers set for the middle of the day. Rural lines, including single-wire earth return (SWER) supplies, can have tighter connection limits, so we confirm what Essential Energy will approve before quoting.
New EV owners, Coffs Harbour
18kWh a day now · adding an EV doing 15,000km a year
An average EV uses 15–18kWh per 100km, so 15,000km a year adds roughly 6–7kWh a day. Their real target is closer to 25kWh a day.
What we’d suggest: a 10kW inverter with about 13kW of panels, the most a standard single-phase home can usually take. Charging the car at home during the day turns what would have been cheap exports into free driving.
What Makes Sizing Different on the Mid North Coast
National calculators assume a generic Australian roof. Ours aren’t generic.
Summer isn’t as strong as you’d think. Humid afternoons and storm cloud rolling in off the ranges knock the top off summer production, so the gap between our best and worst months is smaller than in inland NSW. Winter is the month to design around.
Gum trees and hills cast long winter shadows. A roof that’s clear in December can lose its first two hours of sun in June when the sun sits low behind a ridge or a stand of blackbutts. We check shading for the winter sun angle, not the day we visit.
Salt air changes the hardware, not the size. Homes close to the beach at Sawtell, South West Rocks, Lighthouse Beach or Forster need panels rated for salt-mist exposure and corrosion-resistant mounting. It doesn’t change how many kilowatts you need, but it should be on your quote.
Storms make backup worth sizing for. If you lose power every time an east coast low comes through, part of your system size should be about keeping the fridge, pump and lights running, which is where a home battery comes in.
| Season | Approx. kWh per kW per day | 6.6kW system per day |
|---|---|---|
| Summer (Dec–Feb) | 4.5–5.5 | 30–36kWh |
| Autumn (Mar–May) | 3.5–4 | 23–26kWh |
| Winter (Jun–Aug) | 2.8–3.2 | 18–21kWh |
| Spring (Sep–Nov) | 4.5–5.2 | 30–34kWh |
Indicative figures for a north-facing, unshaded roof between Coffs Harbour and Forster. Individual days vary a lot with cloud.
Panels, Inverters and Export Limits
Why so many systems are “6.6kW”. Clean Energy Council rules let you install up to 133% of your inverter’s rating in panels and still claim the federal solar rebate. A 5kW inverter × 1.33 = 6.65kW, which is where the familiar 6.6kW comes from. The same rule puts about 13.3kW of panels on a 10kW inverter.
Inverter limits on single phase. Most homes in our area are single phase, where 10kW of solar inverter is the usual ceiling. Bigger homes, pools and workshops are often three phase, which opens up larger systems.
Essential Energy’s export limit. On the Mid North Coast, Essential Energy has generally capped exports at a fixed 5kW. From late 2026 it’s moving to flexible export limits for new and upgraded systems, which can let you export more when the local network has room, and less when it doesn’t. Inverters now need to be connected to the internet and meet the new national standard to get the full benefit — an offline inverter can be held to a much lower export limit. Ask any installer quoting you whether the inverter they’ve chosen is compliant.
What it means for sizing: you can install more panels than you can export, as long as you’ll use or store the extra. That’s why oversizing only makes sense when there’s a battery, an EV, or real daytime load to soak it up.
| System size | Panels (440W) | Roof space needed |
|---|---|---|
| 6.6kW | 15 | ~30m² |
| 8kW | 18 | ~36m² |
| 10kW | 23 | ~45m² |
| 13.2kW | 30 | ~59m² |
Roof space is panel area only. Setbacks from edges, vents, skylights and ridges mean you’ll need a bit more usable roof than this.
Sizing Mistakes We See on Other Quotes
Most of these come from quoting off a postcode instead of a bill.
Matching panels to your total usage
If you use 16kWh a day but only 5kWh of it in daylight, a system sized to “cover your bill” will export most of what it makes for a few cents per kWh. Size for what you’ll actually use, store or charge.
Sizing off a summer bill
A system that looks generous in January can fall well short in July. We always run the numbers against winter output.
Ignoring the next five years
An EV, a pool, a granny flat or kids becoming teenagers can add 5–10kWh a day. Adding panels later means a second inverter or a replacement, so it’s usually cheaper to size for where you’re heading.
Forgetting the battery
If there’s a reasonable chance you’ll add a battery, the panels need enough headroom to charge it on a winter day as well as run the house. A 6.6kW system that’s perfect on its own can be tight once you add a 13kWh battery.
Squeezing panels onto a shaded face
Two extra panels on a south face or behind a tree rarely earn their keep. We’d rather put 13 panels where the sun is than 16 across the whole roof.
Choosing an inverter that can’t do flexible exports
With NSW moving to flexible export limits, an older or non-compliant inverter can cost you export income for the life of the system.
Planning a Battery? Size the Panels First
A battery is only as useful as the solar that fills it. A simple check: on a June day, your panels need to make enough to cover your daytime use plus the battery’s capacity.
Take the Port Macquarie family above. They use about 6kWh during the day and want a 13kWh battery, so they need roughly 19kWh from the roof in winter. A 6.6kW system makes about 20kWh on a June day, so it works, just. A 16kWh battery would push them toward 8kW of panels.
With the federal Cheaper Home Batteries Program taking a meaningful amount off the upfront cost, and the rebate rate stepping down every six months, many of our customers are now designing solar and battery together from day one rather than adding storage later.
Solar Sizing FAQs
Divide the daily kWh you want solar to cover by about 4, the average daily output of 1kW of panels on the Mid North Coast. Most local homes end up between 6.6kW and 13kW. Couples out during the day suit around 6.6kW, while families using 18–25kWh a day, or anyone adding a battery or EV, usually suit a 10kW inverter with about 13kW of panels.
On a north-facing, unshaded roof, a 6.6kW system averages around 26kWh a day across the year. Expect about 18–21kWh a day in winter and 30–36kWh on good summer days. East–west roofs produce roughly 10–15% less over a year but spread generation more evenly through the day.
For a small household with little daytime use and no plans for a battery or EV, yes. For most families it’s now on the small side. Panel prices have fallen, feed-in tariffs have shrunk, and batteries are cheaper with the federal rebate, so a larger system that charges a battery or car usually delivers better value than a 6.6kW system exporting its surplus for a few cents.
Yes. Clean Energy Council rules allow up to 133% of the inverter’s rating in panels while still qualifying for the federal solar rebate. That’s why a 5kW inverter commonly carries 6.6kW of panels, and a 10kW inverter carries around 13.3kW.
Homes on the Essential Energy network, which covers the Mid North Coast, have generally had a fixed export limit of 5kW. From late 2026 Essential Energy is introducing flexible export limits for new and upgraded systems, which vary through the day with network capacity. Your inverter needs to be internet-connected and compliant with the new NSW requirements to benefit. Your installer should confirm the approved limit for your address before installing.
Usually, yes. On a winter day your panels need to cover your daytime use plus the battery’s capacity. An EV driven 15,000km a year adds roughly 6–7kWh a day. Most households planning either one are better suited to a 10kW inverter with about 13kW of panels on a single-phase connection.
Yes. An east–west array makes about 10–15% less energy over a year than a north-facing one, but it produces more in the early morning and late afternoon, when many households actually use power. Adding one or two panels to make up the difference is often the better choice than squeezing everything onto a small north face.
Not for most homes. Single phase usually allows up to 10kW of solar inverter, which supports around 13kW of panels. Homes that need more than that, often acreage, homes with pools and ducted air, or small businesses, may benefit from three-phase power. We’ll tell you at the site visit whether you already have it.
They’re fine for a ballpark but they don’t know your roof pitch, shading, export limit or when you use power. The biggest errors we see come from calculators assuming too much daytime use and ignoring winter. A proper design uses your actual interval data from your retailer or Essential Energy.
Across the Mid North Coast of NSW, including Coffs Harbour, Sawtell, Woolgoolga, Bellingen, Urunga, Nambucca Heads, Macksville, Kempsey, South West Rocks, Port Macquarie, Wauchope, Laurieton, Taree, Wingham and Forster-Tuncurry. If you’re nearby but not listed, give us a call and we’ll tell you honestly whether we’re the right fit.
Send Us Your Bill. We'll Do the Maths.
Free, no obligation, and sized from your actual usage rather than your postcode.
We’ll look at your usage pattern, check your roof on satellite and in person, confirm what Essential Energy will approve at your address, and come back with a recommended system size with the reasoning written down. If a smaller system makes more sense for you, we’ll say so.
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