Is a 6.6kW solar system right for your home?
A 6.6kW system suits a typical family home using 12–20 kWh during daylight hours. In Melbourne it produces about 24.7 kWh daily on average, covering most daytime needs and exporting the rest for a feed-in credit. Homes with higher daytime use—especially those running pools, heat pumps or electric vehicle chargers—capture more of the output directly. Check your electricity bills: size for your daytime usage first, then add panels to cover exports and future load growth. If summer bills are much lower than winter, solar will flatten that gap.
Who a 6.6kW system suits
- 2–4 people using 12–20 kWh a day
- Homes with daytime use: pool pump, air conditioning, home office
- Homes that may add a battery later (bigger needs: 10kW)
- Roofs with 31–36 m² of usable, mostly unshaded space
How a 6.6kW system works
Solar panels
14–17 panels · 31–36 m²
The panels turn sunlight into DC power. Facing north, east or west with little shade from 9am to 3pm gives the best yearly output.
Inverter
5 kW (panels up to 133% of inverter)
The inverter converts DC to the AC power your home uses and controls what goes back to the grid. It is the part most likely to need replacing in the system’s life.
Your switchboard
Solar first, grid second
Your home uses solar power first; anything left over is exported for a feed-in credit, and the grid tops you up at night or on cloudy days.
Monitoring
App or web portal
Monitoring shows production and use by the hour, so you can move dishwasher, washing and EV charging into sunny hours and spot faults early.
How much does a 6.6kW solar system cost in Victoria?
A 6.6kW system costs $4,500–$7,000 after the STC (Small-scale Technology Certificate) discount of about $1,482 that installers claim and pass to you on the invoice. The final price depends on panel and inverter brands, roof type, number of storeys, switchboard upgrades and local labour rates. A north-facing single-storey roof with clear space costs less to install than a multi-level roof with obstacles or a switchboard that needs rewiring. Request an itemised quote from at least two installers and compare the warranty lengths for panels and inverter, not only the headline price.
6.6kW system prices and output by city
| City | Output a day | Output a year | STC discount | Price | Payback |
|---|
| Sydney, NSW | 25.6 kWh | 9,326 kWh | $1,710 | $4,500–$7,000 | — |
| Brisbane, QLD | 27.5 kWh | 10,039 kWh | $1,710 | $4,500–$7,000 | 3.6–7 yrs |
| Adelaide, SA | 27.3 kWh | 9,973 kWh | $1,710 | $4,500–$7,000 | 2.6–5.2 yrs |
| Perth, WA | 29.8 kWh | 10,883 kWh | $1,710 | $4,500–$7,000 | 3–5.8 yrs |
| Melbourne, VIC | 24.7 kWh | 9,016 kWh | $1,482 | $4,500–$7,000 | — |
| Parramatta, NSW | 25.2 kWh | 9,181 kWh | $1,710 | $4,500–$7,000 | 3.4–6.7 yrs |
| Penrith, NSW | 25.7 kWh | 9,392 kWh | $1,710 | $4,500–$7,000 | 3.3–6.5 yrs |
| Newcastle, NSW | 26.5 kWh | 9,676 kWh | $1,710 | $4,500–$7,000 | — |
Output from NREL PVWatts per city. STC discount at each city’s zone and the current certificate price. Prices are market guidance (estimates), not quotes.
6.6kW compared with 10kW
A 10kW system typically costs $6,500–$10,500, producing 13,660 kWh a year. The 6.6kW option at $4,500–$7,000 and 9,016 kWh annually suits homes that use less daytime power and have limited roof space. Larger systems spread fixed costs like design, approvals and electrician time across more panels, lowering the per-kilowatt cost. A 10kW system also qualifies for the same network rebate, so the cost advantage of scale is real but modest. Choose the size that matches your actual daytime usage to avoid exports you cannot use.
| System | Typical price | Output a year | Price per kW |
|---|
| 6.6kW | $4,500–$7,000 | 9,016 kWh | $871 |
| 10kW | $6,500–$10,500 | 13,660 kWh | $850 |
What changes the price of your quote?
- Roof: tile, tin or flat, pitch and storeys (and whether scaffolding is needed)
- Panel and inverter brand and warranty length
- Switchboard upgrades and meter changes
- Single- or three-phase supply and your network’s export limit
- Shading fixes such as optimisers or microinverters
Why the cheapest 6.6kW quote can cost more
A very low quote often signals unknown panel brands with no Australian warranty support, a basic inverter prone to overheating, or a one-year workmanship warranty instead of five to ten. Replacing a failed inverter in year four costs $1,500–$2,500 and loses years of solar generation; a system with quality parts and a proper warranty runs reliably for 25 years. Your energy bill savings are worth protecting.
How much power does a 6.6kW solar system produce?
A 6.6kW system produces about 9,016 kWh per year in Melbourne, averaging 24.7 kWh daily. Output varies by location: Sydney reaches 25.6 kWh daily, Brisbane 27.5 kWh, Adelaide 27.3 kWh, Perth 29.8 kWh, Parramatta 25.2 kWh, Penrith 25.7 kWh and Newcastle 26.5 kWh. Cloudier regions and those farther south produce less; sunnier regions produce more. East-west split arrays produce slightly less total output but spread generation across more daylight hours, raising self-consumption.
How output changes through the year
Summer days produce well above the annual average because daylight lasts over 14 hours and the sun sits high; winter days produce roughly half the summer average because daylight is under 10 hours and the sun is low in the sky. Plan for winter electricity bills to fall less than summer bills because solar cannot close the entire gap. Adding a battery stores summer surplus for winter, but the payback is longer than solar panels alone.
How much of it will you use?
Most homes use about 25–35% of their solar output as it is generated, taking power directly during the middle of the day, and export the rest for a feed-in credit. Shifting dishwashing, laundry, pool pumps and EV charging into midday hours raises self-consumption and reduces what you export at a lower credit rate. A 6.6kW system producing 24.7 kWh daily means roughly 12 kWh is spare on an average day—available for a battery or the grid export credit. The more daytime load you can move, the higher your saving.
How much will a 6.6kW system save, and when does it pay back?
At Parramatta power prices a 6.6kW system saves about $1,050–$1,323 per year based on typical self-consumption and export rates. The payback period runs 3.4–6.7 years depending on your roof angle, shading, electricity usage and local tariffs. After payback, the system produces close to free power for the remaining 20+ years of its panel life. Brisbane payback is 3.6–7 years; Adelaide 2.6–5.2 years; Perth 3–5.8 years. Your own bill determines your actual saving—use a detailed quote that factors your usage patterns.
Work out the saving for your bill
Enter your recent electricity bill and daily usage into our calculator to see your projected annual saving, payback timeframe and the system size that matches your roof and budget. The calculator estimates self-consumption based on your daily pattern and local feed-in credit rates, then shows the payback across different system sizes. Results are personal to your home and location, not a generic estimate.
Open the solar size & savings calculator →
How many panels does a 6.6kW system need?
A 6.6kW system needs 14–17 solar panels depending on the panel wattage. Modern panels range from 390 W to 475 W per panel: a 390 W system needs 17 panels, 420 W needs 16, 445 W needs 15, and 475 W needs 14 panels. Higher-wattage panels are slightly more efficient and take up a little less roof space, but all deliver the same total power output. The panel brand, not the count, matters most for durability and warranty support.
Panels and roof space by panel size
| Panel rating | Panels needed | Area per panel | Panel area in total |
|---|
| 390 W | 17 | 1.8 m² | 31 m² |
| 420 W | 16 | 2.0 m² | 31 m² |
| 445 W | 15 | 2.1 m² | 31 m² |
| 475 W | 14 | 2.2 m² | 31 m² |
Area from a typical 21.5% efficient panel; allow extra for edge clearances and walkways.
How much roof space does a 6.6kW system need?
A 6.6kW system needs about 31 m² of panel surface area. Once you add clearances from roof edges, gutters and obstacles, and gaps between rows for safety and cleaning, plan for 31–36 m² of usable roof space. A 390 W panel occupies 1.8 m²; 420 W is 2.0 m²; 445 W is 2.1 m²; 475 W is 2.2 m². Most homes have this on a north-facing roof; east–west split layouts spread production across the day and reduce shading from chimneys or trees at different times.
What size inverter suits a 6.6kW system?
A 5 kW inverter is the standard match for a 6.6kW system. Australian regulations allow panel capacity up to 133% of inverter rating, which is why 6.6kW of panels pairs with a 5 kW inverter without breaching rules. Your network operator may also set an export limit for your site—for example, 5 kW—which the inverter respects automatically. A separate document from your installer will confirm the inverter size and your network limits before installation.
What’s included in a 6.6kW solar package?
A complete 6.6kW solar quote must itemise every component by brand and model: the number and wattage of panels, the inverter, switchboard upgrades if needed, DC and AC wiring and safety gear, mounting hardware, and a monitoring system or app. Each component should list its warranty term—typically 15–25 years for panels, 5–10 years for inverters and 5–10 years for workmanship. A good installer provides a one-page summary and a detailed appendix with all specifications, prices and warranty terms so you can compare fairly with other quotes.
14–17 solar panels
Check: brand, model, 25-year performance warranty
5 kW inverter
Check: brand, 5–10-year warranty, battery-ready option
Mounting and cabling
Check: rails rated for your wind region, isolators
Monitoring
Check: app access, consumption monitoring
Installation
Check: accredited installer, workmanship warranty in years
Approvals and paperwork
Check: STC discount shown on the quote, network approval
Which brands are used in 6.6kW systems?
Solar Advice installs panel and inverter brands available in Australia with strong warranty support and parts availability. A typical package combines a Tier-1 panel brand—such as Canadian Solar, Longi, Trina or JA Solar—with a well-supported inverter such as Fronius, SMA, Sungrow or Goodwe. All carry multi-year manufacturer warranties and local service networks. Cheaper systems sometimes use brands with no local support; if a fault occurs, repair or replacement becomes difficult. Your quote should list every brand, model and warranty by name.
Solar panels
AikoCanadian SolarJinkoLONGiRECSunPower (Maxeon)Trina
Inverters
EnphaseSolarEdgeSungrowFroniusGoodWeHuawei
Batteries
BYDEnphaseSigenergySolarEdgeSungrowAlpha ESSEnphase IQ BatteryFranklinWH
6.6kW solar with a battery
Adding a battery to a 6.6kW system stores daytime surplus for evening and night use, raising self-consumption and reducing grid purchases when tariffs are higher. A 6.6kW system makes about 24.7 kWh daily on average in Melbourne, meaning roughly 12 kWh is available to store after you use power during the day. A 10 kWh battery suits homes that use 8–12 kWh in the evening; a 13.5 kWh battery suits those using 12–15 kWh after dark. Batteries cost more upfront and pay back more slowly than panels, but incentives like virtual power plant schemes shorten the timeframe.
How much does a 6.6kW system with a battery cost?
| Battery | Battery installed | Incentives | 6.6kW solar + battery |
|---|
| 10 kWh | $9,000–$13,000 | − $2,520 | $10,980–$17,480 |
| 13.5 kWh | $12,150–$17,550 | − $3,402 | $13,248–$21,148 |
| 20 kWh | $18,000–$26,000 | − $4,434 | $18,066–$28,566 |
Incentives: Cheaper Home Batteries. Market guidance, not quotes; incentive amounts change on set dates.
What size battery suits a 6.6kW system?
A 10 kWh battery is typical for a 6.6kW system. Since the system produces about 24.7 kWh daily and most homes use 25–35% during the day, roughly 12 kWh is spare—perfectly sized for a 10 kWh battery that rarely overfills and always has charge available by evening. A 13.5 kWh battery suits homes with higher evening loads of 12–15 kWh; a 20 kWh battery is rare unless you want 24-hour autonomy or run heavy evening loads. Oversizing the battery means it will not fully charge most days, wasting the cost.
Does a battery pay back?
In many Australian regions, government rebates and virtual power plant payments reduce the payback to 8–12 years, bringing it closer to solar panels alone. Current incentives vary by state; confirm what applies to your postcode before deciding.
Rebates and finance for a 6.6kW system
Several rebates apply to 6.6kW systems in Victoria. The federal STC (Small-scale Technology Certificate) discount of about $1,482 is claimed by the installer and deducted from your invoice. Some regions offer additional state-level rebates for solar or batteries; check with your local council. Virtual power plant schemes in some areas pay you for letting the network use your battery during peak demand. Confirm current rebate amounts and eligibility with your installer, as incentive amounts and programs change annually.
Cheaper Home Batteries
About $252/kWh for the first 14 kWh, $151/kWh to 28 kWh and $38/kWh to 50 kWh (2026 rate)
Source: DCCEEW Cheaper Home Batteries, from 1 May 2026, checked 2026-10-16
Small-scale Technology Certificates (STCs)
Upfront discount: kW × zone multiplier × deeming years × STC price
Source: SRES: zone multiplier × 5-year deeming × $38 per STC, checked 2026-10-16
Solar Victoria hot water rebate
up to $1,400 locally made, $1,000 other
Source: Solar Victoria, from 1 July 2026, checked 2026-10-16
Solar Victoria panel rebate
up to $1,400
Source: Solar Victoria, from 1 July 2026, checked 2026-10-16
How a 6.6kW installation works
From your first call to full switch-on typically takes 4–6 weeks, most of it waiting for network approvals and STC paperwork; the physical installation itself is usually one working day. The process starts with an assessment of your roof, shading and switchboard, followed by a design and detailed quote. Once you approve, the installer applies for network connection and STC registration. After approval, the installation team fits the panels and inverter, then the network operator changes your meter and your system is energised and monitored.
- 01
Assessment
An assessment begins with a review of your recent electricity bills to understand your usage pattern and size the system correctly. The installer inspects your roof in person or via satellite images to check the angle, direction, space and shading from trees, chimneys or nearby buildings. The switchboard is checked to see if rewiring is needed for the inverter and monitoring. This information feeds into the design and cost estimate.
- 02
Design & quote
A detailed design shows the exact panel layout across your roof faces, the inverter size and expected annual output for your location. The quote lists every component by brand and model, the total price before and after STC discount, warranty terms, and the expected payback time based on your bills. A clear one-page summary and a full technical appendix make it easy to compare with other quotes. Ask for clarification on any item before you commit.
- 03
Approvals
The installer handles approvals on your behalf. Your network operator must approve the connection before installation; this usually takes 2–3 weeks and is free. The STC (Small-scale Technology Certificate) paperwork is lodged with the Clean Energy Regulator to claim the rebate discount. Most installers finish all approvals before the installation date, so you avoid delays on the day.
- 04
Installation day
Installation day typically runs 6–8 hours. The team mounts the rails and panels on your roof, runs DC cabling to the inverter, fits the inverter in your switchboard or nearby, adds an isolation switch and safety equipment, then wires the AC side back to the meter. They leave the system off until the network has approved the connection. A good installer tidies up and leaves a one-page commissioning checklist showing what was installed.
- 05
Switch-on & monitoring
After network approval, the installer switches on your system and changes your meter to a smart meter that records both import and export. You receive a walk-through of your monitoring app or web portal where you can watch live output, daily totals and feed-in credits. Most systems also log data to the cloud so you can check performance from your phone. A technical checklist confirms all safety tests are passed.
6.6kW solar system questions
How much does a 6.6kW solar system cost?
Usually $4,500–$7,000 after the STC discount. The roof, brands and switchboard work set the final price.
How many kWh does a 6.6kW system produce per day?
About 24.7 kWh a day on average in Melbourne (9,016 kWh a year), more in summer and less in winter.
How many panels are in a 6.6kW system?
14–17 panels: 14 with 475 W panels or 17 with 390 W panels.
How much roof space does a 6.6kW system need?
About 31 m² of panels, or 31–36 m² of roof once clearances are allowed for.
What size inverter is used with a 6.6kW system?
Usually 5 kW, because panels can be up to 133% of the inverter rating.
What is the payback on a 6.6kW system?
About 3.4–6.7 years at Parramatta power prices, saving $1,050–$1,323 a year.
What battery suits a 6.6kW system?
Usually a 10–13.5 kWh battery; about 12 kWh is spare on an average day.
Is 6.6kW enough for my home?
It suits typical family homes of two to four people. Check your last 12 months of bills against the output above.
Can I expand a 6.6kW system later?
Yes, if your roof has space and your network allows. Most installers design the first system to leave room for extra panels on an east or west face. Network connection rules apply to the total capacity; confirm your site limit with your network operator before adding panels. Expanding the inverter is harder and usually not worth the cost.
Does a 6.6kW system work on a metal or tile roof?
Both work equally well. Metal roofs are lighter and faster to install. Tile roofs may need more time if the installer must remove and reset tiles around the mounting rails. Roof type affects the labour cost but not the final power output or warranty.
What happens to a 6.6kW system on a cloudy day?
On an overcast day a 6.6kW system produces roughly 30–50% of its clear-day output, depending on cloud density. Winter cloud cover is thicker than summer cloud, so winter days produce much less. This is why most homes still buy grid power even with solar; the system covers daytime use on good days and exports the surplus.
Do I need a separate meter for a 6.6kW system?
Yes, you will need a smart meter that records both power imported from the grid and power exported back to it. The network operator installs this for free as part of the connection approval. Your installer handles the meter change request.
Helpful links
