Frequently asked questions
Straight answers about solar, batteries, and saving money on your energy bills in Perth.
How much does solar actually save in Perth?
An entry-level 6.6kW system in Perth generates about 28kWh on an average day. A home without a battery typically uses about 32% of that directly (avoiding 33.26c/kWh grid power) and exports the rest at Synergy's solar export rates (DEBS). For a typical Perth home, our model puts that at about $1,200 a year. With a battery, the share of solar used at home typically rises to about 58%, so the savings grow with it. Your own number comes down to how and when you use power, so run our calculator for an estimate built on your bill.
How long does solar take to pay for itself?
For an entry-level 6.6kW system in Perth, our typical-home model puts payback at about 4.7 years, on an installed price with the federal STC discount already taken off (about $1,800 off for a system installed today). Actual results vary with system size, installed price, usage, roof orientation, and shading. DEBS pays export credits only on systems of up to 5kW of inverter capacity (for example 6.6kW of panels on a 5kW inverter). On a larger system, exported power earns no credit, so its savings come from the solar you use at home. A battery is best judged over its life rather than on a simple payback, and its value depends mostly on how much power you use in the evening and overnight, so our calculator works it out from your bill. Size it to that evening use: undersizing is the costly mistake, because adding capacity later usually means a second installation. A battery also adds backup power and lets you store more of your own solar instead of selling it back cheaply. These figures assume current Synergy rates; Synergy's latest annual price change raised the A1 rate by 2.75%.
What rebates are available in WA?
Two main rebates: (1) Federal STCs: an upfront discount applied by your installer, currently worth about $1,400-$3,600 for a typical 5-13kW solar system in Perth Zone 3 installed today. This reduces each year until 2030. (2) WA Battery Scheme: $130/kWh for Synergy customers (max $1,300, 10kWh cap). Your battery must be on Synergy's Supported Solutions List (SSL). Both rebates can be claimed together.
Is BillWise really free?
Yes. All calculators, analysis tools, and recommendations are free for WA households. We make money when you request quotes. Installers pay a referral fee to receive your enquiry. This fee is paid by the installer, not you. We don't receive commissions from manufacturers, and we don't inflate savings estimates to push you toward more expensive systems. Our disclosure page explains this in detail.
Should I get a battery or just solar?
It depends on how and when you use power. Solar on its own costs less upfront. A battery adds more when most of your use is in the evening, when you want backup during outages, or when you want to use more of your own solar than the 32% or so a solar-only home typically uses directly. For evening-heavy homes, a bigger array plus a battery often wins. If you already have solar and are on the A1 tariff, pairing a battery with Midday Saver changes the numbers, so model both, and get a hybrid inverter replacement quoted alongside an AC-coupled battery: in WA, adding a battery to an existing system counts as an alteration. Our calculator gives an estimate based on your bill. It is an estimate, not financial advice.
What tariff should I be on?
Most Perth households without solar are fine on A1 (flat rate at 33.26c/kWh). If you have solar, Midday Saver is often better: you pay just 8.85c during solar hours (9am-3pm) but 55.33c during peak (3-9pm). It's worth switching if your 3-9pm usage is below 28.8% of your total. If you have an EV, the EV Add-On tariff drops overnight charging to 19.92c. Our calculator recommends the best tariff for your specific usage pattern.
How does Synergy billing work?
Synergy bills roughly every 60 days (not quarterly). Each bill shows your supply charge (~$1.19/day) plus energy usage. The average Perth household pays $300-$600 per billing period. If you have solar, your bill also shows export credits (DEBS or REBS). You receive about 6 bills per year.
Will I still have power during a blackout with solar?
Solar panels alone shut down during a blackout (safety requirement, they can't feed power into a dead grid). You need a battery with backup capability to keep power during outages. Not all batteries support backup. Check the specs. Typical 10kWh batteries can run lights, fridge, and internet for 8-12 hours. Larger systems (13.5kWh+) can power most of a house overnight.
What happens after I request quotes?
Up to 3 installers in the WattMate network in your area receive your details. An installer from the WattMate network will be in touch by phone or email. You're under no obligation. Compare their quotes, ask questions, and take your time deciding. We don't share your details beyond the matched installers, and you control who contacts you.
How accurate are the savings estimates?
Our estimates use real Synergy tariff rates (updated when rates change), Bureau of Meteorology solar data for Perth, and current federal/state rebate values. They assume typical installation conditions (north-facing roof, minimal shading, standard equipment). Your actual savings may vary based on your specific roof angle, shading, equipment quality, and usage patterns. We recommend using our estimates as a starting point and getting a site assessment from an installer for precise figures.
Still have questions?
Run the calculator for an answer built on your own usage, or email us and a real person will help.