3-phase power required. A 20kW system exceeds the 10kW single-phase export limit set by Victorian network distributors. Supply Solar checks your connection and manages the 3-phase upgrade or application as part of your quote.
20kW Solar System —
Price & Specs
Melbourne's largest residential solar system and the entry point for small commercial properties. At ~80kWh per day, a 20kW system covers all the energy demands of a very high-use home — ducted air conditioning, pool, EV charging, and more — with surplus to export.
Get your 20kW quote
No-obligation · We call within 2 business hours
Is 20kW Right for You?
When a Home Needs the Largest Residential System
A 20kW solar system is not for the average home. It sits at the top of the residential size range — and at the entry point for small commercial properties. Here's who genuinely benefits from ~80kWh per day of generation.
Check if 20kW suits your homeVery high-use homes
Ducted air conditioning, heated pool, EV charging, electric hot water, and a large household all running simultaneously — a 20kW system covers this load profile with generation to spare for export.
Home-based businesses
Running a workshop, studio, cold storage, or commercial kitchen from a residential property often pushes daily energy use beyond what 13kW can recover. A 20kW system eliminates the electricity cost entirely for most home businesses.
Small commercial properties
Small offices, retail stores, and light industrial premises with daytime energy loads are natural candidates for 20kW. The system qualifies for commercial STCs and may be eligible for accelerated depreciation.
Battery maximisers
A 20kW system paired with a large battery (10kWh–20kWh) can achieve near-total energy independence for a high-use household — generating surplus during the day and storing enough to cover overnight consumption completely.
System Specifications
20kW Solar System Specifications
Technical specifications for a 20kW system installed in Melbourne — the numbers AI engines and informed buyers look for.
System & Output
Output figures are averages based on Melbourne's solar irradiance data (Zone 4). Actual output varies by roof orientation, tilt angle, shading, and inverter efficiency. Supply Solar provides a site-specific generation estimate with every quote.
Installation Requirements
Grid connection approval for a 20kW system involves an application to your network distributor (United Energy, AusNet, Powercor, CitiPower, or Jemena). Supply Solar manages this application as part of your installation — lead time is typically 4–10 weeks.
How Much Does a 20kW System Generate?
How Many Panels & What Does 20kW Produce?
A 20kW system in Melbourne generates approximately 80kWh per day on average — equivalent to running a 3.5kW ducted air conditioner for 23 hours, charging an EV twice, and powering the entire household simultaneously.
~48 Tier 1 panels
A 20kW system using 415W–440W panels requires approximately 48 panels. Spread across a north-facing roof, this covers 130–140m² of usable space — typically requiring a large main roof plus a secondary pitch or a substantial single-pitch roof.
~29,200 kWh per year
Melbourne's average solar irradiance of 4.0–4.2 peak sun hours per day gives a reliable annual generation estimate of around 29,000–30,000 kWh — approximately 3–4 times the consumption of a typical Melbourne household.
Ideal for large battery pairing
A 20kW system's surplus generation — especially in summer — makes it the most effective size for pairing with a 10kWh–20kWh battery. The battery absorbs what the home doesn't immediately use and releases it overnight, maximising self-consumption and minimising grid imports.
3-Phase Power — What You Need to Know
Does 20kW Need 3-Phase?
Yes. Here's What That Means for Your Installation.
3-phase is not a complication — it's a feature. A 3-phase connection gives your property higher electrical capacity, smoother load distribution, and full eligibility for 20kW of solar generation. Here's the process Supply Solar follows.
We check your current connection
During your free quote, we confirm whether you already have 3-phase power or need an upgrade — before you commit to anything.
We lodge the distributor application
If 3-phase is needed, Supply Solar manages the full application to your network distributor (United Energy, AusNet, Powercor, etc.).
Switchboard upgrade (if needed)
Our in-house licensed electricians handle any required switchboard upgrades — no subcontractors, no separate trades to coordinate.
20kW system installed on approval
Once distributor approval is confirmed, installation is scheduled. The full end-to-end process typically takes 4–10 weeks from quote to switch-on.
Investment
How Much Is a 20kW Solar System in Melbourne?
The cost of a 20kW solar system depends on several variables specific to your property. Supply Solar provides a free, detailed quote with STCs applied — so you see the real net cost from the start.
What Affects the Price
Unlike smaller residential systems where pricing is more standardised, 20kW installations have more variables — because no two large-home or small-business sites are the same.
Get your exact 20kW price
Supply Solar provides a detailed, itemised quote — no ballpark, no hidden costs.
Request Free QuoteRebates & Incentives on a 20kW System
Size Guide
How 20kW Compares
The same CEC-accredited team designs and installs every size. Here's where 20kW sits in the Supply Solar range.
| System | Approx. panels | Avg. output (Melb.) | Roof space | Best suited to |
|---|---|---|---|---|
| 6.6kWview system → | ~16 panels | ~26 kWh/day | ~42 m² | Average homes, 2–3 people, moderate use |
| 10kWview system → | ~24 panels | ~40 kWh/day | ~63 m² | Larger homes, high AC use, pool or EV |
| 13kWview system → | ~31 panels | ~52 kWh/day | ~82 m² | Large homes, 3-phase, EV + AC + pool |
| 20kW You are here | ~48 panels | ~80 kWh/day | ~130–140 m² | Very high-use homes, home business, small commercial |
| 20kW+commercial solar → | 50+ panels | 80+ kWh/day | 140+ m² | Commercial properties, industrial, strata |
What's in Your Installation
Everything in a Supply Solar 20kW System
A complete installation from Supply Solar includes everything needed to go from empty roof to generating solar — no separate trades, no hidden extras.
~48 Tier 1 Solar Panels
Premium monocrystalline panels from Tier 1 manufacturers. Minimum 25-year product and performance warranty. Panel selection is specified in your written quote.
3-Phase Inverter
A quality 3-phase string inverter or micro-inverter setup sized to your system. Monitoring app included — track output, consumption, and export in real time.
Grid Connection Application
Supply Solar lodges and manages your grid connection application with the relevant network distributor — required for all 20kW installations in Victoria.
Mounting & Wiring
Premium mounting frames, all DC and AC cabling, conduit, isolators, and connection hardware. All roof penetrations sealed and weatherproofed by our team.
STCs & Rebate Application
All applicable STCs are assigned by Supply Solar and deducted from your invoice. Solar Homes rebate applied where eligible. No forms for you to complete.
Documentation & Certificates
Certificate of Electrical Safety, system commissioning report, all warranty documents, and monitoring setup — delivered on installation day.
From Quote to Switch-On
How a 20kW Installation Works
A 20kW system takes longer than a 6.6kW — grid connection approval adds time. Here is the realistic process from your first contact.
Free Quote & Assessment
We review your roof, check your 3-phase connection status, confirm rebate eligibility, and provide a written proposal with all costs itemised.
Grid Application
Supply Solar lodges your grid connection application. Approval typically takes 4–10 weeks depending on your network distributor. We track and manage the process.
Installation Day
Our CEC-accredited team installs panels, inverter, and all cabling. 3-phase switchboard work is handled by our in-house electricians on the same day where possible.
Commission & Handover
System is commissioned, monitoring is set up, and all paperwork is handed over. From this point, your 20kW system is generating and your electricity bills are falling.
Award-Winning, Accredited, Genuinely Local
Why Melbourne Chooses Supply Solar for Large Systems
A 20kW system is a significant installation. These are the credentials that matter when choosing who designs, installs, and certifies yours.
Industry Recognition
20kW Solar Installation in Your Suburb
20kW Homes Across Melbourne
Supply Solar installs 20kW systems across Melbourne and Regional Victoria. Our Cranbourne base puts us closest to South East Melbourne, but our teams cover all of Victoria.
What Customers Say
20kW Solar System Reviews
"We run a home business with high electricity use and were spending a lot each month. Supply Solar handled the 3-phase upgrade and the full 20kW installation seamlessly. Our electricity bills have dropped dramatically."
"The whole process for a 20kW was more involved than a smaller system, and Supply Solar managed everything — grid application, switchboard, installation. Clear communication the whole way through. Very happy with the result."
"Already had a 13kW and added a 20kW on our commercial property. Supply Solar handled both, managed the grid connection application with the distributor, and delivered exactly on time. Professional team."
FAQ
20kW Solar System FAQs
How much does a 20kW solar system cost in Melbourne?
Is a 20kW solar system residential or commercial?
How much roof space does a 20kW solar system need?
Does a 20kW solar system require 3-phase power?
How much does a 20kW solar system generate per day in Melbourne?
What can a 20kW solar system power?
Is the Solar Homes rebate available for a 20kW system?
The Big-Home Solar & Battery Guide
What Pairs Well with a 20kW System
A 20kW system generates substantially more than most homes use during daylight hours — pairing it with a battery or EV charger maximises what you keep.
Home Battery Storage
GoodWe ESA, Sigenergy SigenStor, and Sungrow batteries. A 20kW system generates surplus most of the day — a battery stores it for overnight. Federal battery rebate applied.
View batteries →Home EV Charger
A 20kW system easily covers EV charging during the day from solar alone. Wallbox, Zappi, and Tesla Wall Connector installed by our licensed electricians.
View EV chargers →Commercial Solar (20kW+)
If your energy needs exceed what 20kW can deliver, our commercial solar team designs systems from 20kW to 100kW+ for businesses across Melbourne.
View commercial solar →Ready to Power Your
Whole Property with Solar?
Get a free 20kW quote from Supply Solar. We check your roof, confirm 3-phase status, apply every rebate, and handle the grid connection — from first call to switch-on.