Getting Three Quotes Is Good Advice. Reading Them Is the Hard Part.
Ask anyone in the solar industry and they will tell you to get at least three quotes before committing. It is solid advice. The problem is that most homeowners receive those quotes, see three different prices for what looks like the same system, and have no clear way to understand why they are different.
Two quotes for a ‘6.6kW solar system’ in Perth can be separated by thousands of dollars — and both can be technically accurate descriptions of what is being offered. The difference is in the details: the panel brand and model, the inverter, what is included in the installation, how warranties are structured, and whether the system has actually been designed for your property or copied from a template.
This guide walks through every line item you should expect to see on a solar quote, what each one means, and how to compare quotes that look similar but are not.
System Size: You Need Two Numbers, Not One
Most quotes describe a system by a single number — ‘6.6kW’ or ’10kW’ — but this shorthand can mean different things. A solar system has two capacity figures that both matter:
- Panel capacity (kWp): the total wattage of all the solar panels combined. A ‘6.6kW system’ typically means panels totalling 6,600 watts of peak output.
- Inverter capacity (kW): the maximum AC output the inverter can deliver to your home or export to the grid. A 5kW inverter can only export 5kW regardless of how many panels are producing.
In Western Australia, Synergy limits single-phase grid exports to 5kW. This is why 6.6kW panels with a 5kW inverter is the standard residential configuration in Perth. You maximise what you can generate while staying within the export limit.
A quality quote states both figures clearly: panel total in kWp and inverter rating in kW. A quote that says only ‘6.6kW system’ without specifying the inverter capacity is missing a critical detail.
Oversizing the array when adding a battery
When your quote includes a hybrid inverter and battery, there is a strong case for oversizing the solar array beyond the standard 133% inverter ratio. Here is why: with a hybrid inverter, excess solar generation that cannot be exported does not get clipped and wasted. It goes directly into the battery via DC-to-DC charging, which is the most efficient way to charge a battery.
In practical terms, a 10kW or larger array on a 5kW hybrid inverter makes good sense in Perth. The 5kW export cap means afternoon generation that would otherwise be curtailed can instead fill the battery for evening use. This is a legitimate design choice that better-designed solar-plus-battery quotes will reflect — and it is worth asking your installer to explain the array sizing rationale if you are including a battery.
Panel Specifications: Brand, Model, and Wattage
‘Premium 410W solar panels‘ tells you almost nothing. A quality quote names the exact manufacturer and model number — for example, ‘LONGi Hi-MO 7 410W’ or ‘SunPower Maxeon 430W’ — so you can look up the specifications, compare them across quotes, and verify what you are actually getting.
Why does the specific model matter when wattage is the same? Because panels with identical wattage ratings can differ significantly in:
- Degradation rate: how much output the panel loses per year. Better panels degrade more slowly, maintaining higher output over a 25-year lifespan.
- Temperature coefficient: how much output drops as the panel heats up. Perth summers mean panels regularly hit 60–70°C. A lower temperature coefficient means less performance loss on hot days.
- Manufacturer warranty and support: a 25-year product warranty from a brand with a strong Australian presence is worth more than the same warranty from a brand with no local operations.
- Build quality and reliability: some panels are rated for more demanding weather conditions, including high wind loads and salt air exposure.
If a quote lists only a generic description — ‘Tier 1 panels’, ‘premium mono panels’, or a brand name without a model — ask for the specific model before comparing prices. A quote without model-level detail has not been built for your property; it is been assembled from a catalogue.
Inverter Specifications: The Most Overlooked Line Item
The inverter is the component most likely to need attention over the life of your system. Panel technology is relatively simple and reliable; inverters are more complex and do more work. The brand and model on your quote matters.
What to look for on the inverter line of your quote:
- Brand and model number: a specific model like ‘Fronius Primo GEN24 5kW’ or ‘Sungrow SH5.0RS’ gives you something to verify. A generic ‘5kW string inverter’ does not.
- Inverter type — standard or hybrid: a standard (string) inverter converts solar DC power to AC for your home. A hybrid inverter does the same but also includes a battery port. If there is any chance you will add a battery in the future, a hybrid inverter from day one avoids the cost of replacing the inverter later.
- Warranty: quality inverters carry 10-year standard warranties, often extendable. A short warranty on an inverter is a signal about expected reliability.
- Monitoring: most modern inverters include monitoring software. The quote should specify what monitoring platform is included and whether there is any ongoing cost.
A quote with well-specified panels but a vague inverter line — or vice versa — is not a complete proposal. Both need to be named, modelled, and warranted.
The STC Rebate on Your Quote: Fixed or Unfixed?
Most solar quotes in Australia show two prices: a gross price (before rebate) and a net price (after rebate). The rebate comes from the federal Small-scale Technology Certificate (STC) scheme, which provides a point-of-sale discount on eligible solar systems.
The critical question is whether the STC price has been fixed on your quote or not. STC values fluctuate with the spot market — they are traded certificates, not a fixed government payment. Some installers lock in the STC price at the time of quoting; others leave it variable, which means the price you signed for might change before installation.
Ask directly: is the STC rebate on this quote fixed at today’s value, or is it subject to change? A reputable installer fixes the rebate at the time of contract.
For battery quotes: the Cheaper Home Batteries Program (CHBP)
The same principle applies to the CHBP rebate on battery systems. The CHBP provides a point-of-sale discount calculated from the battery’s STC assignment — and that value steps down every six months as the scheme approaches its end date. Your quote should show the CHBP rebate as a line item, confirm the current rate, and ideally fix it at the time of contract.
Note: Current CHBP rebate values (mid-2026) are approximately $258 per kWh for the first 14 kWh of capacity, stepping down for larger systems. Confirm current figures with Positive Energy Solutions at time of purchase.
Installation Inclusions: What is In and What Is not
Two quotes at different prices for the same equipment often diverge on installation scope. Items that appear standard are not always included, and a quote that excludes them will look lower-cost until those costs appear separately.
Check that the following are explicitly included in any quote you are comparing:
- Mounting rails and hardware: the racking system that holds panels to the roof. Quality rail systems are designed for Australian wind and load requirements.
- DC and AC cabling: all cable runs from panels to inverter, and inverter to switchboard. Long cable runs (particularly on large roofs or two-storey homes) add cost that should be accounted for upfront.
- Switchboard connections and upgrades: connecting the inverter to your switchboard requires electrical work. If your switchboard needs upgrading to accommodate the new system, this cost should be identified at quoting stage, not presented as a surprise on installation day.
- Tilt frames and non-standard mounting: if your roof pitch is not optimal for Perth’s sun angle, tilt frames can improve generation. Some installers quote these as extras; others include them where the system design calls for it.
- Monitoring hardware and setup: the gateway or communications device that connects your inverter to its monitoring platform, and the time to configure it and walk you through how to use it.
- Scaffolding or elevated access: required for some roof types and double-storey homes. This is sometimes listed as a separate variable cost — check whether it is included or conditional.
- Grid connection paperwork: in WA, new solar installations require Western Power network application and approval. This should be managed by the installer as part of the installation process, not left to you.
- Payment terms: reputable installers take a deposit — typically 10 to 20 percent — with the balance due on completion. A quote or contract that requires full payment upfront before installation is a significant risk and not standard practice among established companies.
When comparing quotes with different prices, go through this list item by item. What looks like a $1,500 saving can disappear quickly once excluded items are added back.
Warranty: Two Separate Things, Both in Writing
Solar warranties are often presented as a single figure — ’25-year warranty’ — without clarity on what is actually being warranted. There are two distinct warranties on every solar installation:
- Product warranty: provided by the manufacturer, covering defects in the panels, inverter, or battery. Panel product warranties are typically 10–15 years; performance warranties (guaranteeing a minimum output level) are typically 25 years. Inverter warranties vary by brand and model — typically 5–12 years standard, extendable on some models.
- Workmanship warranty: provided by the installer, covering the quality of the installation itself: mounting, cabling, roof penetrations, switchboard work. This is entirely separate from the manufacturer warranty and is the installer’s personal guarantee of their work.
Both should be specified on your quote with clear durations and a stated process for making a claim. A workmanship warranty that exists only as a verbal assurance, or as vague language like ‘we stand behind our work,’ provides no real protection.
Positive Energy Solutions provides a 10-year installation workmanship warranty, and is your single point of contact for the manufacturer product warranties on your panels, inverter and battery. This workmanship warranty also covers balance-of-system components (isolators, cabling, monitoring hardware) — the parts most likely to need attention in the early years. Both warranties are confirmed in writing.
The Generation Estimate: If It is Not There, Ask Why
Every quality solar quote includes an estimated annual energy production figure for your specific property — in kilowatt-hours per year, ideally broken down by month. This figure is calculated using your roof orientation, tilt, shading profile, and local irradiance data.
The generation estimate matters for two reasons: it lets you model the financial return of the system against your actual electricity bills. It tells you whether the system has been designed for your property or templated from a generic 6.6kW assumption.
A quote without a generation estimate means one of two things: the installer has not done a proper site assessment, or they are avoiding giving you a figure they would be held to. Either way, ask for it before proceeding.
The estimate should also account for Perth’s specific solar profile — high annual irradiance but with significant seasonal variation, and afternoon generation that may be subject to export limits if you are not running a battery.
Why Two Quotes for the ‘Same’ 6.6kW System Look Completely Different
Here is a concrete illustration of how two quotes can describe the same system size but represent fundamentally different value:
Both quotes might be for ‘6.6kW solar systems.’ The price difference between them is real and justified — but it is only visible if you know what to look for.
What a Positive Energy Solutions Quote Includes
Every quote from Positive Energy Solutions is built for your specific property — not templated. Here is what you can expect to see:
- Full equipment specification: panel brand, model, and wattage; inverter brand, model, and type (standard or hybrid); battery brand and model if included. No generic descriptions.
- System sizing rationale: panel kWp and inverter kW stated separately, with a clear explanation of why that configuration suits your home and usage profile.
- Array oversizing explanation (where applicable): if a battery is included and the array is sized to take advantage of DC-to-DC charging, this will be explained — not assumed.
- STC and CHBP rebates fixed at point of contract: the rebate you are quoted is the rebate you receive, without fluctuation between signing and installation.
- WA Battery Scheme enrolment: handled as part of the installation process for eligible systems — not left for you to navigate separately.
- Generation estimate: annual kWh estimate with monthly breakdown based on your roof orientation, tilt, and shading.
- Warranty detail: 10-year installation workmanship warranty, in writing with a clear claims process, plus the manufacturer product warranties.
- After-sales support: Omnidian after-sales program explained upfront — proactive monitoring, single point of contact for the life of the system.
- SAA-accredited installation: Positive Energy Solutions works with multiple SAA-accredited installation teams. Accreditation details for your assigned team are confirmed at the time of scheduling.
If you would like to see what a fully itemised solar or solar-plus-battery quote looks like for your property, Positive Energy Solutions can provide one from the showroom in Osborne Park or via an online enquiry.
Get a Fully Itemised Quote From Positive Energy Solutions
Positive Energy Solutions provides detailed, itemised solar and battery quotes for Perth homes — with every specification named, every rebate fixed, and every warranty documented. Visit the showroom in Osborne Park, call the team, or submit an enquiry online.
- How to Choose a Solar Installer in Perth — /how-to-choose-solar-installer-perth
- Why Getting a Battery With Your Solar Makes More Sense Than Adding One Later — /solar-battery-together-perth-2026
- What Is the Cheaper Home Batteries Program and How Does It Work in Perth? — /lower-cost-home-batteries-program-perth-2026
- DC-Coupled vs AC-Coupled Solar Batteries — /dc-coupled-vs-ac-coupled-solar-batteries
- How to Choose a Solar Battery in Perth — /how-to-choose-solar-battery-perth
Related guides
- How to Read Your Synergy Bill After Solar Perth: What Has Changed and What It All Means
- How to Compare Solar Quotes Perth 2026: Panels, Batteries and Rebates Explained
- Before Your Solar Is Installed in Perth: What to Expect From Sign-Off to Installation Day
- How Much Solar Battery Storage Do I Need? Perth 2026 Guide
Frequently Asked Questions
How many solar quotes should I get in Perth?
At least three is the standard recommendation. But the number matters less than your ability to compare them properly. Three quotes with no understanding of the differences is less useful than two quotes you can read clearly. Use the line items in this guide to make sure you are comparing equivalent proposals.
What does ‘Tier 1 panels’ mean on a solar quote?
Tier 1 is a financing classification originally developed to assess manufacturer bankability — it has nothing to do with product quality or reliability. A quote that describes panels as ‘Tier 1’ without naming the brand and model is not giving you meaningful information. Ask for the specific manufacturer and model number.
Can I negotiate a solar quote in Perth?
You can ask questions and seek clarification — and a good installer will welcome that. Be cautious about negotiating purely on price, as the response is often to reduce inclusions or switch to lower-cost components rather than to reduce margin. A better approach is to use the line items in this guide to ensure you are comparing equivalent proposals, then make a decision based on total value rather than headline price.
How long is a solar quote valid for in Perth?
Quote validity varies by installer, but STC rebate values change with the market, so quotes with unfixed STCs can change fairly quickly. Most quotes are valid for 30 days. If your quote has a fixed STC price, confirm in writing how long that price is guaranteed.
Should I get a quote that includes a battery even if I am not sure I want one yet?
Yes — it is worth asking for both options. A combined solar-plus-battery quote lets you compare the two scenarios side by side. It also prompts the conversation about inverter type: if a quote for solar-only uses a standard inverter, adding a battery later means either replacing the inverter or AC-coupling the battery, both of which add cost. A hybrid inverter from day one keeps your options open.
About the Author
Jason Wiktorowicz
Sales Manager, Positive Energy Solutions | Perth, WA
Jason has been at the centre of Western Australia’s energy transition for over a decade. As Orchestration Lead on Project Symphony — WA’s largest virtual power plant pilot — and Stream Lead on Project Encore, he worked directly with AEMO, Western Power and Energy Policy WA to shape how distributed energy resources connect and operate on the SWIS. That work included developing and rolling out CSIP-AUS, now mandatory for all new WA grid connections. He also led Emergency Solar Management (ESM), the first program of its kind in WA, VPP for Schools (VPP4S), which provided direct market benefits through Supplementary Reserve Capacity, and REBAR, the WA Residential Battery Rebate scheme.
His earlier career spanned Synergy, Infinite Energy and Curtin University’s Sustainability Policy Institute, where he co-authored peer-reviewed research on net-zero urban precincts, solar integration and peer-to-peer energy trading, published in the journal Urban Planning in 2018.
At Positive Energy Solutions, Jason leads sales with a focus on system design accuracy and long-term performance. Positive Energy Solutions installs solar and battery systems, EV chargers and heat pumps, and holds partner accreditations with Fronius, SigEnergy, iStore and SunPower. Connect with him on LinkedIn.
