Comparing Solar Quotes: What Every Homeowner Must Check
Solar
When comparing solar quotes, the first thing to line up is the cash price after Small-scale Technology Certificates (STCs) alongside the system size in kilowatts, the named inverter and panel models, and all four written warranties. Everything else is secondary until those four items match across every quote you’re holding.
Here’s the quick checklist to run on every quote before you read another word:
- Cash price after STCs (and any state rebate): this is the real out-of-pocket number
- System size: total kW and number of panels, with per-panel wattage stated
- Estimated annual production: in kWh, with the modelling assumptions listed
- Inverter and panel specs: brand, model, type (string, micro, or hybrid)
- Warranties: product, performance/degradation, inverter, and workmanship — all in writing with durations
- On-site visit: confirmed before the quote was finalized, not assumed
According to energy.gov.au, you should get quotes from at least three suppliers, and each quote should list system size, equipment make and model, generation estimates, rebates, and warranties. That’s the floor, not the ceiling.
Pro Tip: Before you call a single installer, pull out three months of electricity bills. Note your daily average consumption in kWh. Every production estimate you receive should be checked against that number — not just accepted.
Table of Contents
- What should a complete Australian solar quote include?
- How do you read and verify production estimates?
- What do costs, financing, and Australian incentives actually mean for your quote?
- How do you get every installer quoting on the same terms?
- What red flags should you watch for, and what should you ask?
- What does the installation process look like from start to finish?
- What extra details matter when a quote includes a battery?
- How Solarxenergy prepares a trustworthy local quote
- Key Takeaways
- The one thing most homeowners get wrong when comparing quotes
- Solarxenergy offers free, transparent quotes for Illawarra homeowners
- FAQ
What should a complete Australian solar quote include?
A quote that’s missing key fields isn’t just incomplete — it’s a signal about how that installer operates. Solar Victoria’s guidance and CHOICE’s installer advice both flag the same pattern: vague quotes tend to foreshadow vague service.
Here’s what a credible, complete quote must contain:
Pricing
- Pre-rebate cash price and post-STC cash price, clearly separated
- Statement of who claims the STCs (usually the installer, who deducts the value upfront)
- Any applicable state rebate applied or noted (e.g., Solar Victoria incentives where eligible)
Equipment
- Panel brand, model name, wattage per panel, and efficiency rating
- Total number of panels and total system size in kW
- Inverter brand, model, type (string inverter, microinverter, or hybrid), and rated output
- Mounting/racking system brand and material
- Cabling type and DC isolator details
Warranties
- Product warranty on panels (typically 10–15 years)
- Performance/degradation warranty (typically 25 years, guaranteeing output above a stated percentage)
- Inverter warranty (typically 5–12 years, varies significantly by brand)
- Workmanship warranty from the installer (typically 5–10 years)
All four must be in writing. Verbal promises are unenforceable, and the claim process for each warranty should be spelled out in the contract.
Installer credentials
- Clean Energy Council (CEC) accreditation number for the installer
- Electrical contractor licence number
- Public liability and workers’ compensation insurance details
- Confirmation of whether installation crew are in-house or subcontracted
CHOICE specifically flags subcontracting as a risk point: if work is subcontracted, warranty enforcement becomes complicated because the entity that sold you the system may not be the one who installed it.
Timeline and validity
- Quote validity period (typically 30 days)
- Expected milestones: site visit, design sign-off, network application, installation, meter change, and grid connection
| Quote Field | What to Look For | Red Flag |
|---|---|---|
| Cash price | Post-STC figure stated explicitly | Only pre-STC price shown |
| Equipment | Brand + model for panels and inverter | Generic “Tier 1 panel” with no model |
| Workmanship warranty | Written, 5+ years, claim process stated | Verbal only, or absent |
| CEC accreditation | Accreditation number listed | “CEC member” without a number |
| Site visit | Confirmed before quote was finalized | Quote sent without a visit |
| Subcontracting | In-house crew confirmed | “Qualified installers” with no detail |
Pro Tip: Ask the installer to send you the product spec sheets for the panels and inverter as separate PDFs. If they can’t, the model numbers on the quote may not match what gets installed.
How do you read and verify production estimates?
Estimated annual production is the number installers use to project your savings. It’s also the number most likely to be optimistic. Two quotes for the same 6.6 kW system can show annual production figures that differ by 20% or more, simply because of different assumptions.
The inputs that drive the estimate are:
- Roof orientation and tilt: north-facing at 20–25° typically maximises output in Australia
- Shading: trees, chimneys, neighbouring rooftops — even partial shading cuts output significantly
- System losses: wiring losses, soiling, temperature derating, and inverter efficiency
- Inverter clipping: if the inverter is undersized relative to panel capacity, peak output is clipped
- Export assumptions: how much of your production is exported vs. self-consumed
- Retail tariff and feed-in tariff (FiT): the rates used to calculate dollar savings
Every quote should name the simulation tool or method used (common options include PVSyst, PVWatts, or a proprietary tool), and state the tariff and FiT rates assumed.
Use this template to capture and compare each quote’s production claim:
If two quotes show very different annual kWh figures for the same system size on your roof, ask each installer to explain the difference. One of them is almost certainly using a more favorable assumption.
Pro Tip: Use your billing history and a self-consumption tool to model your own estimate before accepting any installer’s projection. Installer estimates can mis-size systems when they assume an idealized export or consumption pattern that doesn’t match how you actually use power.
What do costs, financing, and Australian incentives actually mean for your quote?
Price comparisons only work when you’re comparing the same number. The most common mistake is comparing a pre-STC price from one installer against a post-STC price from another.
Understanding the price layers
STCs (Small-scale Technology Certificates) are the federal government’s upfront solar incentive. Most installers deduct the STC value from the price before quoting, but not all do. Always confirm which price you’re looking at. For NSW homeowners, current rebate and incentive details are worth checking before you sign anything.
The $/Watt figure is a useful normalizer. Divide the post-STC cash price by the total system wattage to get a per-watt rate. A 6.6 kW (6,600 W) system at $7,000 post-STC works out to roughly $1.06/W. That figure lets you compare systems of different sizes on a level basis.
For typical price context: CHOICE data shows common price ranges of approximately $4,500–$8,000 for a 5 kW system, $5,500–$9,000 for a 6.6 kW system, and $8,000–$13,000 for a 10 kW system, with payback periods often in the 2–6 year range depending on tariff and feed-in rates.
Finance traps to watch for
“No-interest” or “interest-free” finance offers from installers often carry establishment fees, monthly account fees, or deferred interest clauses that add hundreds of dollars to the total cost. Always ask for the comparison rate, not just the headline rate.
Hidden cost checklist — confirm these are included in scope:
- Switchboard upgrades (often required for larger systems or older homes)
- Scaffolding or roof access equipment
- Meter reconfiguration or network application fees
- Removal and disposal of existing panels (if applicable)
- Any required roof repairs before installation
Pro Tip: Always ask for the cash price, even if you plan to finance. The cash price exposes what the system actually costs and lets you calculate the true cost of any finance offer by comparing it to that baseline.
How do you get every installer quoting on the same terms?
The apples-to-apples problem is real. Industry experts consistently flag that rushed or vague quotes often foreshadow service issues — and that comparing headline prices without aligning assumptions is how homeowners end up disappointed.
Step-by-step: how to standardize your quotes
- Define your energy target upfront: tell each installer your average daily consumption (kWh/day from your bill) and ask them to size the system to meet it, or ask each to quote on the same fixed system size.
- Give every installer the same tariff inputs: your current retail rate (¢/kWh) and your current or expected feed-in tariff.
- Confirm site visit status: only accept quotes from installers who have either visited your property or explicitly note the quote is subject to a site assessment.
- Request the cash price on every quote, regardless of whether finance is offered.
- Ask each installer to name their modelling tool and list the assumptions used.
Comparison table template (copy into a spreadsheet):
Documents to request from each installer:
- Itemized quote with all line items
- Panel and inverter product spec sheets (PDF)
- Warranty certificates or warranty terms document
- Evidence of CEC accreditation (accreditation number or certificate)
- Site assessment photos or written report
- Electrical contractor licence number
What red flags should you watch for, and what should you ask?
Some warning signs are obvious. Others are buried in the fine print or only surface when you ask the right questions.
Red flags to reject or query immediately:
- Line items listed as “solar system” with no brand or model breakdown
- No written workmanship warranty, or a warranty that covers “defects” but excludes labour
- Production estimates with no stated assumptions (orientation, shading, tariff)
- “Free solar” offers or aggressive limited-time pricing pressure
- Quotes sent without a site visit having been completed
- No CEC accreditation number, or “CEC member” claimed without a verifiable number
Ask every installer these questions before you sign:
“Has a site visit been completed, or is this quote subject to one?”
“Who will perform the electrical sign-off, and are they your employee or a subcontractor?”
“Who handles the STC paperwork — you or me?”
“What happens if the switchboard needs an upgrade — is that included in this price?”
“If I have a warranty claim in five years, who do I call?”
Seller tactics to watch for:
- Component substitution: the quote names one panel brand, but a different brand arrives on installation day. Insist on a contract clause that requires your written consent for any substitution.
- Variation claims at installation: switchboard upgrades, extra cabling, or roof access costs that weren’t in the original scope. The cheapest quote often hides these as post-contract variations. Insist all foreseeable scope items are listed upfront.
- Upselling at installation: pressure to add monitoring hardware, extended warranties, or battery preparation at the last minute, when you’re least positioned to compare prices.
Pro Tip: If an installer won’t answer the subcontracting question directly, that’s your answer. The entity responsible for your workmanship warranty should be the same one doing the work.
What does the installation process look like from start to finish?
Knowing the sequence helps you spot delays and know when to push for updates.
- Site visit and final design (1–3 days after initial quote): the installer assesses your roof, switchboard, and metering setup. The final system layout is confirmed, and any scope variations are documented.
- Contract signing: you sign the final contract with the agreed scope, price, and equipment list. Do not sign until the site visit is complete.
- Network application and approvals (1–4 weeks): the installer lodges a connection application with your network distributor (e.g., Ausgrid or Endeavour Energy in NSW). This step is often the longest and most variable.
- Equipment procurement (1–2 weeks, sometimes concurrent with approvals): panels, inverter, and mounting hardware are ordered. Lead times vary by brand and season.
- Installation day (typically 1–2 days): panels, inverter, and cabling are installed. Confirm the final layout matches your approved design before work begins.
- Electrical sign-off and compliance certificate: a licensed electrician issues a Certificate of Compliance for Electrical Work (CCEW). You should receive a copy.
- Meter reconfiguration and grid connection (1–4 weeks after installation): your retailer or network operator reconfigures your meter to record export. The system should not be commissioned for export until this is complete.
- Commissioning and handover: the installer walks you through the monitoring app, confirms system output, and provides all warranty documents.
Homeowner checks at key stages:
- Before signing: confirm all scope items are listed, site visit is complete, and equipment matches the quote
- Installation day: photograph the installed equipment labels (panel and inverter serial numbers)
- After installation: request the CCEW and confirm meter reconfiguration is lodged
- At handover: verify monitoring is active and you can read live production data
Pro Tip: Ask what to expect at each stage before you sign — a good installer will walk you through the timeline without being prompted.
What extra details matter when a quote includes a battery?
Battery-inclusive quotes need a second layer of scrutiny. The headline “10 kWh battery” tells you almost nothing useful on its own.
Battery specifications to request:
- Usable capacity (kWh): not gross capacity — the usable figure after depth-of-discharge limits
- Chemistry: lithium iron phosphate (LFP) is currently the most common residential chemistry in Australia, valued for its thermal stability and cycle life
- Round-trip efficiency: the percentage of energy you get back for every kWh stored; typically 90–95% for quality units
- Usable depth of discharge (DoD): most quality batteries allow 90–100% DoD on usable capacity
- Cycle life or warranty period: stated as either a number of cycles (e.g., 6,000 cycles) or a calendar period (e.g., 10 years), whichever comes first
- Backup capability: does the battery provide whole-home backup during a grid outage, or only partial backup? This requires specific hardware (a backup gateway or similar)
- Inverter compatibility: confirm the inverter is a hybrid model that supports the battery, or that a separate battery inverter is included in the quote
How batteries change the economics:
Adding a battery shifts the self-consumption calculation significantly. Instead of exporting surplus solar at a low feed-in tariff, you store it and use it at night at the full retail rate. Whether that math works in your favor depends on your consumption profile, your FiT rate, and the battery’s cost. Ask the installer to show you the payback calculation with and without the battery so you can see the incremental cost of storage.
| Battery Spec | What to Ask | Why It Matters |
|---|---|---|
| Usable kWh | “Is this usable or gross capacity?” | Gross figures inflate apparent size |
| Round-trip efficiency | “What percentage do I get back?” | Affects actual savings calculation |
| Backup type | “Full home or partial backup?” | Determines outage protection level |
| Warranty basis | “Cycles or years, whichever first?” | Cycle-based warranties suit high-use homes |
| Inverter type | “Is the inverter hybrid or AC-coupled?” | Affects future expandability |
Pro Tip: Choosing the right battery upfront is far cheaper than retrofitting. If there’s any chance you’ll add storage later, ask for a hybrid inverter now — replacing a string inverter to add a battery typically costs $1,500–$3,000 in additional labour and equipment.
How Solarxenergy prepares a trustworthy local quote
Solarxenergy is a locally-owned solar provider serving homeowners across the Illawarra region, including Wollongong and Shellharbour. Every quote starts with an in-person site visit — not a satellite image assessment, not a phone estimate. The site visit confirms roof condition, shading, switchboard capacity, and metering setup before any price is committed to paper.
The quote Solarxenergy provides is fully itemized: post-STC cash price stated explicitly, panel brand and model named, inverter brand and model named (including type), all four warranty types listed with durations and claim contacts, and the modelling assumptions used to generate the production estimate. STC handling is managed by Solarxenergy, so the deduction is already applied to the price you see.
Installation is performed by Solarxenergy’s own crew, not subcontractors. That matters for warranty enforcement: the same team that installs your system is the team that responds if something needs attention later.
Solarxenergy holds a 5-star Google rating built on transparent, end-to-end service: from the first site visit through to helping you find the best electricity retail deal after installation. For homeowners in the Illawarra who want a quote they can actually compare, that transparency is the starting point.
Pro Tip: Ask any installer you’re considering whether their crew is in-house or subcontracted. Then ask the same question of Solarxenergy — the answer will tell you something about both.
Key Takeaways
Comparing solar quotes properly means aligning cash prices, modelling assumptions, and warranty terms before any headline figure means anything.
| Point | Details |
|---|---|
| Always compare post-STC cash prices | Pre-STC and post-STC prices can differ by thousands; confirm which figure each quote shows. |
| Demand all four warranties in writing | Product, performance, inverter, and workmanship warranties must each be written with durations and claim processes. |
| Align modelling assumptions first | Production estimates are meaningless unless orientation, shading, tariff, and FiT inputs match across quotes. |
| Check subcontracting status | In-house crews simplify warranty claims; subcontracted work can complicate accountability. |
| Solarxenergy as a local benchmark | Solarxenergy provides itemized, post-STC quotes with named equipment, in-house installation, and a 5-star rating across the Illawarra. |
The one thing most homeowners get wrong when comparing quotes
The conventional wisdom says to get three quotes and pick the best value. That’s not wrong, but it misses the real problem: most homeowners compare three quotes that aren’t actually comparable.
The inverter is where this plays out most visibly. A budget string inverter and a premium hybrid inverter can look like a $1,500 price difference on paper. What that gap actually represents is the difference between a system that’s battery-ready and one that will need a full inverter replacement to add storage later. Inverters are the most common point of failure in a solar system, and choosing a lower-quality unit to save money upfront often costs more over a 10-year horizon.
The workmanship warranty is the other one that gets glossed over. Homeowners focus on the 25-year panel performance warranty — which is a manufacturer commitment, not an installer commitment — and don’t notice that the installer’s own workmanship warranty is for two years, or is absent entirely. If your roof develops a leak at the penetration points three years after installation, the panel manufacturer won’t cover it. Only the installer’s workmanship warranty does.
Monitoring setup is a third blind spot. A system with no monitoring app or a monitoring setup that requires a separate subscription is a system you can’t easily verify is performing as promised. Ask every installer what monitoring is included, whether it’s free, and how you access it.
The practical fix is simple: use the comparison table in this article, fill it in for every quote, and don’t make a decision until every row is populated. A quote that can’t fill in those rows isn’t ready to be accepted.
Solarxenergy offers free, transparent quotes for Illawarra homeowners
Getting a quote that actually tells you what you need to know shouldn’t require a checklist and three follow-up calls. Solarxenergy’s approach starts with a free on-site assessment, produces a fully itemized quote with named equipment and post-STC pricing, and includes a walkthrough of the modelling assumptions so you know exactly what the savings projection is based on.
For homeowners in Wollongong, Shellharbour, and across the Illawarra, Solarxenergy handles the STC paperwork, uses in-house installation crews, and provides ongoing support after the system is live — including help finding the best electricity retail deal for your new setup. Battery-ready system design is available for homeowners who want to add storage now or keep that option open later.
Ready to see what a complete, transparent quote looks like? Get a free quote from Solarxenergy or explore solar panel installation options for Wollongong and Shellharbour to see what’s available for your home.
FAQ
What should a good solar quote include?
A complete solar quote should list the post-STC cash price, system size in kW, panel and inverter brand and model, all four warranty types in writing (product, performance, inverter, workmanship), CEC accreditation details, and the modelling assumptions behind the production estimate. Energy.gov.au recommends getting at least three quotes and checking that each includes equipment specs, generation estimates, and rebates.
What is a solar quotation?
A solar quotation is a formal written offer from an installer that details the system design, equipment, total price (before and after government incentives like STCs), warranties, and expected energy production for your specific property. It should be based on a completed site visit, not a generic estimate.
How do you compare solar quotes on an apples-to-apples basis?
Ask every installer to quote on the same system size or energy target, use the same tariff and feed-in tariff assumptions, and provide the cash price after STCs. Then compare $/Watt, warranty durations, and modelling inputs side by side — not just the headline price.
Who is a reputable solar installer in the Illawarra region?
Solarxenergy is a locally-owned, 5-star-rated solar provider serving Wollongong, Shellharbour, and the broader Illawarra region, offering fully itemized quotes, in-house installation crews, and end-to-end support from site visit through to post-installation retail advice.
How long does solar installation take in Australia?
From signed contract to grid connection, the typical timeline is 4–10 weeks. Network approval in NSW is usually the longest step, often taking 2–4 weeks, while the physical installation itself typically takes 1–2 days.
