How to negotiate a solar quote in Perth
Solar installers in Perth expect some negotiation. Knowing which parts of a quote are fixed, which are flexible, and what alternatives to ask about can reduce the cost of a quality system without compromising on what matters.
Yes, you can negotiate a Perth solar quote, and installers expect you to. They receive dozens of enquiries a week and routinely discount on request, because most installations carry a 20–40% gross margin on components. What you can't negotiate is compliance and accreditation. Knowing which is which gets you a fair price without cutting corners.
If you're not yet sure what system to ask for, WattMate's free energy audit report works it out from your home's own details first.
What is typically negotiable in a solar quote?
The price itself, the panel model, the inverter brand, the panel count and the install date. A 20–40% gross margin (the share of the component price left after costs) leaves room, and installers compete on price, especially in the 2025–2026 market. Residential volumes have been higher than in earlier years, so asking for a better price is normal and rarely gets a quote withdrawn.
Panel model. Panels from large, established makers on the Clean Energy Council register vary in price by 15–25%. If a quote includes a higher-priced panel, such as Jinko Tiger Neo, Canadian Solar HiHero or REC Alpha, a lower-priced alternative on the register could cut the cost by $500–$1,200. That is worth discussing. Compare the warranty terms of both. Don't trade into an unknown brand: stick with panels on the Clean Energy Council (CEC) approved list, from makers with 5+ years of clean warranty history in Australia.
Panel count. A 6.6kW system is the entry-level "oversizing" configuration in WA, where the panels outsize the inverter. If your roof fits slightly fewer panels, going from 16 panels to 15 (approximately 6.2kW) might save $300–$500 and still perform solidly.
Inverter. Single-phase string inverters (one central inverter for the whole array) come from Growatt, Sungrow, Fronius, SMA and others. If a quote includes a higher-priced model, a lower-priced alternative with the warranty you need may be fine for you. The difference can be $400–$800 on a residential inverter.
Timing. Winter (June–August) is usually quieter for Perth installers, and some offer lower prices for off-peak scheduling. Giving 2–4 weeks of notice, rather than asking for a set date, can sometimes save $200–$400 on larger systems.
What parts of a solar quote are not meaningfully negotiable?
Anything the law requires: SAA (Solar Accreditation Australia) accreditation, the Western Power connection, electrical compliance and approved panels. These aren't extras to trade for a lower price, and a quote that is cheap because one of them is missing can cost you more later.
The installer has to be SAA-accredited. Without that, the STCs can't be assigned and the Western Power grid connection can't proceed.
The Western Power network connection (NCN) application is a regulated cost, with the fee and process set by Western Power. A quote that leaves it out, or promises to "handle it cheaper", is a concern.
Electrical compliance means a Certificate of Compliance for the electrical work, plus DC isolators (switches that cut power from the panels) and switchboard upgrades where the WA Electrical Requirements call for them. A quote that skips this work will fail inspection and leave you paying for re-work.
And the panels have to be on the CEC product list, because STC assignment requires CEC-listed products. If a quote swaps a named panel for an unknown one that isn't listed, decline. An unknown brand with no Australian service presence may also leave you with a warranty you can't claim on.
How do you negotiate a solar quote effectively?
Get at least three written quotes from SAA-accredited installers, all priced after the small-scale technology certificate (STC) rebate is assigned, each with a line-item breakdown. Quotes for the same approximate system size often vary by $1,000–$2,500 in Perth. Then ask a specific question about each gap.
Three quotes put you in a strong position. If you're still collecting them, get quotes from Perth installers in the WattMate network. Compare like with like: the same approximate size (6.6kW), panel model and inverter model.
Be specific about what you want matched. "Quote B from [installer name] has the same 6.6kW Jinko system for $1,200 less. Can you match it or come within $500?" gets a real answer. A vague request for "your best price" usually gets very little.
Check that every quote is "after STC rebate assigned". That means the installer claims the Small-scale Technology Certificates for you and the price shown is already reduced by their value. If one quote is gross (before STCs) and another is net, you're not comparing the same number. The complete Perth solar rebates guide covers what should already be taken off a compliant quote.
Ask for each cost on its own line: panels (brand, model, unit cost and count), inverter (brand and model), mounting hardware, electrical labour, the NCN application fee and any switchboard work. That's where you'll see why two quotes differ.
Should you ask for a battery-ready quote?
If a battery is possible at any point, yes. Ask for a "solar now, battery-ready" price with a hybrid inverter (one unit that handles both solar and battery, and the default for a new install) and a quoted price for adding the battery. A hybrid inverter costs $800–$2,000 more upfront, and it makes a later battery a DC-coupled addition, connected through the same inverter as the panels.
The alternative is harder. Adding a battery to a string inverter means AC coupling (the battery has its own inverter, connected on the AC side). In WA that counts as an alteration, which in practice brings whole-of-site compliance into play. The battery also needs a gateway on Synergy's approved list, or a same-brand pairing, to keep the rebate, VPP and loan. Better still, ask for a quote with the battery included now, sized to your evening and overnight use, alongside the solar-only price.
What red flags come up in a solar quote negotiation?
A sudden big discount with no reason, brand names held back until signing, and pressure to sign today. A reputable Perth installer should hold a quote for at least 7–14 days.
If an installer drops $2,000 from a quote, ask what changed, and what was removed or substituted to make room for it.
Every quote should name the panel and inverter make and model up front. An installer who won't show brand names until the contract is signed may be planning to substitute equipment.
"This price is only valid today" is a pressure tactic. The STC rebate steps down on a published schedule, annually for solar and half-yearly for batteries, not day by day, so same-day pressure has no rebate basis.
A quote that starts 40% above competitors and drops 30% on request may suggest the first price was inflated for the negotiation. Compare the final price, not the size of the discount.
What should you confirm in writing before signing?
The equipment, the size, the price net of STCs and the warranties, along with the connection paperwork and payment terms. Get all of it in writing:
- Panel brand, model, and watt-rating
- Inverter brand and model
- System total capacity (kW)
- Quote is "net of STC rebate" (STC assignment included)
- Warranty terms: panels (usually 25yr product/performance), inverter (5–12yr depending on brand)
- Installer's workmanship warranty (industry standard: 5yr)
- NCN application included in quote
- Timeline from signing to installation
- Western Power connection process (NCN submission timeframe)
- Deposit and payment schedule
A quote that covers all of this, from an SAA-accredited installer, is one you can hold up against two others on equal terms. Run it through the quote checker before you sign to check the price, components and projected savings against your own usage.