How to Choose a Solar Installer: 12 Checks Before You Sign

A solar system is a 25-year asset on your roof. A cheap installation by an unaccredited electrician might fail inspection, lose you eligibility for rebates, void warranties or underperform by thousands of dollars over its life. A properly accredited installer conducts real assessments, uses tier-one equipment matched to your home, and guarantees workmanship. The difference in upfront cost is often recovered within 1–3 years through genuine performance and warranty protection.

Electricity prices in Australia have risen 20–40% over the past five years, and the trend continues. A correctly sized system cuts your bills far more than an oversized system from a discount installer who doesn't understand your usage. Accreditation, experience and attention to detail are not luxuries—they're the foundation of a system that actually works.

Solar Accreditation Australia (SAA) accreditation is the legal mark of a qualified installer. All grid-connected solar systems in Australia must be installed by an SAA-accredited business with licensed electricians. You can verify accreditation on the SAA register at saasolar.com.au—search by business name, postcode or license number. Unaccredited installers cannot legally connect to the grid, and your Small-scale Technology Certificates (STCs) will be rejected by the Clean Energy Regulator if the installer is not accredited.

Beyond SAA, your electricians must hold a current electrical contractor license from your state—this is issued by different bodies depending on whether you're in NSW, Victoria, Queensland, South Australia, Western Australia, Tasmania or the ACT. Ask the installer for a copy of their team's licenses and the SAA certificate. If they hesitate or say 'trust us', find another installer. Accreditation takes work; legitimate businesses keep it public.

Before any quote, the installer should visit your home in person, walk your roof, take photos and check your switchboard. This assessment identifies real constraints: shading from trees or buildings (which kills production), roof pitch and orientation, materials (tile, metal, flat), structural capacity, and whether asbestos is present. A site assessment also includes a review of your electricity bills from the past 12 months to size the system to your actual usage, not a guess.

A professional installer provides a written site assessment with photos, production estimates and a system proposal within a week. If an installer gives a quote over the phone without visiting, or says they can size your system from Google Maps, move on. A site assessment also flags edge cases: a three-storey home may need a DC isolator on each string; a north-facing roof in a shaded valley produces less than the same system on an open east-west roof. These details matter.

System size is measured in kilowatts (kW). A typical home uses 15–20 kWh per day; a 5 kW system on a sunny roof produces about 20 kWh per day in summer and 8 kWh per day in winter. Oversizing (buying 10 kW when you use 15 kWh/day) wastes money on panels that feed into the grid at low export rates. Undersizing (buying 3 kW) means you still buy power from the grid during the evening and cloudy days. The right size depends on your location (zone), roof aspect, usage pattern and whether you plan to add a battery.

Ask the installer to show you the production estimate for your system, usually provided as a monthly average in kWh. Compare it to your typical monthly consumption from your electricity bill. A well-matched system should cover 50–80% of annual usage; the rest comes from the grid or a battery. If the estimate seems too high or too low, ask the installer to explain the assumptions (panel efficiency, soiling losses, inverter clipping). A transparent installer will walk you through the maths.

Solar panels and inverters come in three tiers: tier-one (global manufacturers with strong warranty support and parts availability—e.g., JA Solar, Jinko, Fronius, SMA), tier-two (regional or newer brands, shorter warranties), and budget (often rebranded, poor support). A tier-one 400 W panel costs slightly more upfront but performs consistently and holds warranty for 25 years. A budget panel saving $200 per system may fail at year 8 with no replacement path.

Ask the installer for the exact panel and inverter model numbers, then check the warranty on the maker's website. Cross-check the brand on your state's distribution network's approved list if one exists. Budget installers sometimes substitute brands mid-project or use older stock; insist on the exact models in your signed contract. If the quote lists 'premium panels' without a model, ask for specifics in writing.

Solar panels include a product warranty (usually 10–12 years, covering defects) and a performance warranty (usually 25 years, guaranteeing at least 80% output). Inverters carry a 5–10 year product warranty. The installer's workmanship warranty covers installation faults for 5–10 years. Your roof may be warranted by the roofer for weatherproofing; if the installer arranges roof work, ask who handles roof leaks and for how long. All warranties must be provided in writing, not verbally.

Read the fine print: some warranties exclude labour, some require annual maintenance, and some are transferable only to the next owner if you sell. Confirm who honours the warranty—the panel maker, inverter maker or the installer—and get their contact details in writing. A reputable installer covers 100% of labour for product defects within the workmanship period; some charge travel or call-out fees after year 2. Cheap systems often come with weak or unclear warranties; clarify this before signing.

A professional installer provides a formal written proposal (not a rough quote), clearly listing system size (kW), panel model, inverter model, racking type, number of panels, labour and materials cost, GST, and the final price. The proposal should also state what's included: site assessment (already done), system design, installation, grid connection paperwork, monitoring app setup, and handover training. It should also list any available federal Small-scale Technology Certificates (STCs) and state rebates, with their current value.

Compare at least three proposals side-by-side, checking that they specify the same or similar system size and equipment tier. A proposal priced $5,000 less than others might use lower-tier equipment, skip monitoring setup, or hide costs in a later 'variation order'. Ask each installer to justify their price and what's included in it. A transparent installer is happy to explain why they cost more or less than a competitor.

Federal Small-scale Technology Certificates (STCs) are the main rebate for residential solar. Your system earns certificates based on size (kW), your location's zone (1–3 depending on solar irradiance), and 5 years of deemed generation. Each certificate is worth $38 (as of 2024; this price is set by the Clean Energy Regulator and may change). A 5 kW system in a zone 3 area (southern Australia) might earn 60–70 STCs, worth roughly $2,280–$2,660. Installers typically pass this discount to you at the point of sale, reducing your out-of-pocket cost.

Some states also offer energy rebates or interest-free loans (e.g., NSW Home Solar battery scheme). Always confirm current rebate amounts with the Clean Energy Regulator or your state energy agency before signing, as amounts change quarterly or annually. Never assume the rebate amount from last year still applies. Factor in rebates when comparing proposals—a system at $8,000 with $2,500 in STCs actually costs you $5,500.

Create a simple table with columns for Installer A, B and C. Rows should include system size (kW), panel model and wattage, inverter model, racking type, labour and materials cost (pre-GST and after GST), STCs value, final cost to you, warranties (panel, inverter, workmanship years), and inclusions (assessment, design, monitoring, handover). This makes it easy to spot which installer offers the best value—not necessarily the lowest price.

Red flags in the table: one installer's price is 30%+ lower than the others and uses budget equipment; another promises the same output with 20% fewer panels (possible if using higher-wattage panels, but ask why); a third skips monitoring app setup (a cost-saving that leaves you blind to problems). The most expensive proposal might use premium equipment and longer warranties, justifying the cost. Use the table to ask follow-up questions before deciding.

After signing, the installer orders equipment (1–3 weeks), arranges any roof work if needed, and schedules installation (usually 1–2 days). Before installation, confirm weather (heavy rain stops roof work) and that you'll be home to let the team in. On installation day, stay available to answer questions; the team will need access to your switchboard and roof.

After installation, an SAA-accredited electrician performs safety tests (continuity, earthing, isolation). The installer then applies to your local distribution network (Ausgrid, Powercor, AusNet, Energex, etc.) for grid connection. This usually takes 2–4 weeks and is done at no extra cost if included in your contract. During this time, your system may be in 'export limiting' mode (limited to 5 kW export) or offline; this is normal. Once the network approves, you're connected and ready to generate.

At handover, the installer explains the monitoring app, shows you how to read your inverter display, and answers questions about maintenance (panel cleaning typically costs $150–$450). Get written contact details for support, the inverter's manual, and a copy of all safety certificates. This is when you pay your final invoice. After handover, your solar journey really begins—watch your app for the first month to confirm the system performs as estimated.

Armed with these 12 checks, you're ready to reach out to installers for site assessments and formal proposals. Start by verifying SAA accreditation on the Solar Accreditation Australia register, then contact 3–4 local businesses in your area. Ask each for a free, no-obligation site assessment and written proposal. Expect to receive proposals within 7 days.

Once you have proposals in hand, use the comparison table in this guide to weigh them fairly. Don't rush: a good installer is worth the extra week of research. After you sign and installation is complete, monitor your system's output for the first few months to confirm it matches the estimate. If it doesn't, contact your installer—they should investigate and fix any issues under the workmanship warranty. Solar is a long-term investment; starting with the right installer makes all the difference.