Before you start: what you'll need
- Proof of property ownership (rates notice, council letter, or title deed)
- A recent Synergy or Horizon Power electricity bill (the NMI is on it)
- Approximate quarterly consumption in kWh and dollars
- If existing solar: the system size in kW
Step 1 - Confirm eligibility (5 minutes)
You're eligible if you tick all of these:
- You own the property (owner-occupier or landlord; not renter).
- The property is in WA, connected to Synergy or Horizon Power.
- You haven't already claimed a battery rebate for this address.
- The battery will be installed by an SAA-accredited installer.
- The battery model is on the SAA approved products list.
If any of those is "no", read our edge cases guide - strata, off-grid, holiday rentals, trust-owned properties all have specific rules.
Step 2 - Run the calculator (30 seconds)
Visit our free calculator. Enter your postcode, quarterly bill amount, current solar size, and the battery size you're considering. The calculator returns:
- WA state rebate amount (auto-detects Synergy or Horizon)
- Federal Cheaper Home Batteries rebate amount
- Net out-of-pocket cost after both rebates
- Annual bill savings estimate
- Payback period
Note the rebate numbers - every installer quote should match them within ±5%.
Step 3 - Get three quotes (60 seconds + 24 hours)
Use our quote request form to be matched with three SAA-accredited installers servicing your suburb. They'll contact you within 24 hours.
Alternatively, find your own installers via:
- The SAA register (verify accreditation)
- The CEC installer directory
- SolarQuotes, ProductReview, Google Reviews (for ratings)
Step 4 - Review quotes (15 minutes per quote)
Every quote should have these line items:
- Battery brand + model + version (e.g. "Tesla Powerwall 3 v2.0", "Sungrow SBR128", "BYD HVS 12.8 with Fronius Symo Hybrid")
- Inverter brand + model (if not built into the battery)
- Cabling, switchgear and labour (line-itemed if possible)
- Federal Cheaper Home Batteries rebate - specific dollar amount, calculated as $/kWh × battery kWh
- WA state Residential Battery Rebate - specific dollar amount, capped at $5,000 (Synergy) or $7,500 (Horizon)
- Net out-of-pocket total (after both rebates)
- Warranty terms - battery manufacturer warranty + installer workmanship warranty
- Estimated install timeline
If a quote is vague about the rebates ("we'll work it out at install time"), push back. A quality installer will rewrite the quote with specific numbers in 10 minutes.
Step 5 - Sign the install agreement (15 minutes)
Choose your installer based on:
- Total net cost after rebates (cheapest isn't always best)
- Battery model choice (must be SAA approved)
- Installer reputation and warranty terms
- Install timeline
Pay the deposit (typically 10% of net cost). The installer lodges the rebate application as part of the install process.
Before paying the deposit, get in writing: "Confirmation that the rebate application will be lodged in my name and at this battery model."
Step 6 - Install day (1–2 days)
The installer arrives, mounts the battery, connects the wiring, commissions the system, and walks you through the app setup. Expect 2–4 hours of power-off during commissioning.
Things to verify on install day:
- The installed battery matches the model on your quote (check the serial number sticker)
- The thermal placement is sensible (not in a sun-baked garage)
- Backup mode works (request a brief grid-disconnection test)
- The app is set up and showing real-time data
Step 7 - Western Power approval (2–4 weeks)
After install, Western Power inspects and approves the system's grid connection. During this period, the battery may operate in standalone mode (charging from solar but not exporting). Most installers handle the Western Power paperwork.
Step 8 - Rebate processing (4–6 weeks)
Federal rebate: already deducted from your invoice. No further action needed.
WA state rebate: processed by Synergy or Horizon Power. Arrives as one of:
- A direct deposit to your bank account (most common)
- A bill credit on your next quarterly statement
- A reduction to the installer's invoice (less common)
If you haven't received the state rebate within 8 weeks of commissioning, contact your installer first - they have visibility into the application status.
Paperwork to keep
- Signed installer quote and invoice
- Battery serial number and model documentation
- SAA accreditation number of your installer
- Western Power connection approval
- Federal rebate STC documentation (from your installer)
- WA state rebate confirmation
Store everything together. If you sell the property, the buyer's solicitor often asks for these documents.
What if the rebate is denied?
Rare, but happens. Most common causes:
- Installer wasn't SAA accredited at the time of install (always check the register beforehand)
- Battery model wasn't on the approved list at time of install
- Property doesn't have a unique NMI (rare; affects some demountables)
- Owner already claimed for this address
If the rebate is denied due to installer error, most install contracts include a clawback clause - the installer absorbs the cost. If denied due to homeowner-supplied info being incorrect, you bear it. Always confirm eligibility in writing before signing.
Common timeline questions
How long from quote to install?
Typically 3–6 weeks. Tesla Powerwall 3 can stretch to 6–10 weeks due to demand.
How long from install to receiving the state rebate?
Usually 4–6 weeks. Up to 10 weeks during peak periods.
How long from sign-up to bill savings?
First full quarterly bill reflecting battery savings arrives 4–8 weeks after commissioning, depending on your billing cycle.