A typical Perth home with 6.6kW of solar with a 5kW inverter will save between $300 and $500 per quarterly bill (Solar Calculator, 2020). This is between $800-$2000 annually! Once you factor in a battery your savings will increase. However, savings depend on three things: how much power you use, when you use it and the size of your system. Below we walk through a real Synergy bill, show you what a 6.6kW system does to it, and explain exactly where the savings come from.
A Typical Perth Synergy Bill — Where Your Money Goes
Before we talk savings, it's important to understand where your money is actually going. In Perth, most households operate under Synergy Home Plan (A1), which is the standard residential tariff for homes in the South West interconnected system (this covers homes from Kalgoorlie all the way to Albany!). A1 customers pay 32.37 cents per kWh for usage and a daily supply charge of 116.05 cents per day (Synergy, 2025).
Below is an example of a typical two-month Synergy bill. This bill takes into account a family of four, using around 25kWh per day. This includes aircon in the summer, electric hot water and a pool pump.
Daily supply charge — 61 days; Rate: 116.05 c/day; Total: $70.79
Electricity usage (A1 tariff) — 1,550 kWh; Rate: 32.37 c/kWh; Total: $501.74
Two-month bill total — $572.53
Over a year, that's approximately $3,435.18 spent on electricity, and roughly $3,010.44 spent on electricity usage. The daily supply charge (about $424.74 a year) stays the same even after you install panels, because it covers the cost of being connected to the grid.
What Tariffs Does Synergy Offer?
Synergy offers two main tariffs, the Home Plan (A1) tariff and the Midday Saver. These tariffs both differ depending on home energy needs. Here's a comparison to help you determine which is best for your home.
Home Plan (A1) tariff — A simple plan for residential properties, with one flat rate for all seasons and a reduced daily supply rate for extra homes on the account. Supply charge: 116.0505 cents per day; supply charge additional homes: 46.1412 cents per day; electricity charge: 32.3719 cents per unit. Available to all customers if electricity is used for residential purposes.
Midday Saver tariff — By shifting electricity use to off-peak hours you could save money, taking advantage of lower rates and helping grid stability. Three time periods apply: Super Off Peak (9am-3pm), Peak (3pm-9pm) and Off Peak (9pm-9am). Supply charge: 129.2269 cents per day; Super Off Peak: 8.6152 cents per unit; Peak: 53.8446 cents per unit; Off Peak: 23.6916 cents per unit. Synergy will organise installation or reprogramming of your meter.
How Much Will Solar Actually Save You?
Using the same example from above, let's imagine the family adds a 6.6kW system to their home — this is the most common size for WA homes. If this was a north-facing 6.6kW system, in a suburb such as Duncraig or Canning Vale, the system will generate approximately 9,500-10,500 kWh per year.
Here's how those kilowatt-hours translate into savings:
Self-consumption savings: If the family uses around 40% of what the system produces directly (roughly 4,000 kWh), they avoid buying that power from Synergy at 32.37 c/kWh — a saving of about $1,295 per year.
Feed-in tariff (DEBS) credits: Any excess solar gets exported to the grid and earns you a credit under Synergy's Distributed Energy Buyback Scheme — that's 10 c/kWh for exports between 3pm and 9pm, and 2 c/kWh at all other times (Synergy, 2025). For a typical Perth home, that's roughly $180–$250 a year in export credits.
Please note: DEBS only applies to systems with a 5kW inverter size or under. Anything above a 5kW inverter size, such as a 10kW, cannot receive DEBS.
That's around $1,500 to $1,800 of savings a year, reducing that $3,435 Synergy bill to roughly $1,600–$2,000 a year. That equates to between $266-$333 every two months! If you add a home battery (eligible for the WA Residential Battery Rebate), the savings can climb even higher.
What Affects How Much You'll Save?
Solar savings aren't a flat number — they swing based on your home, your habits, and your system. The four biggest factors are:
1. System size. A 3kW system can save approximately $748.65 a year, a 6.6kW will save you $1,500-$1,800 a year, and a 10kW+ system (ideal for larger homes) can save $2,000+ more!
2. When you use power. Solar pays you the most when you use it directly. Running your dishwasher, washing machine, pool pump, or aircon during daylight hours is worth three times more than exporting that same energy back to Synergy. During peak hours of 3pm-9pm, if you're using all those appliances, you're likely taking from the grid, inevitably increasing your power bill.
3. Roof orientation and shade. North-facing roofs in Perth are ideal, but east/west splits also perform well because they spread generation across morning and afternoon. Heavy shade from trees or nearby buildings is the main culprit for under-performing systems.
4. Whether you have a battery. Without a battery, any solar you don't use during the day only earns 2–10 c/kWh back. With a battery, that same energy offsets a 32.37 c/kWh grid purchase later in the evening — which is why batteries are so much more attractive in WA after the recent DEBS rate cuts.
Frequently Asked Questions
Will solar eliminate my Synergy bill entirely?
Not entirely, but it will be significantly reduced. You will need to pay a surcharge to be connected to the grid. However, with a well-sized system and battery, your bills will be significantly reduced.
How long does it take for solar to pay itself off in Perth?
Most 6.6kW systems in Perth pay for themselves in 4 to 6 years after the federal STC rebate is applied. After that, every kilowatt-hour of savings is pure return — and quality panels are warranted for 25 years.
Does it matter where in Perth I live?
Only slightly. What's more important is your roof orientation and shading. This can impact where you put your panels and the total power generated.
What if I'm on Horizon Power instead of Synergy?
If you live in regional WA and are supplied by Horizon Power, the basic maths is similar but the DEBS peak and off-peak rates differ slightly. Our team can walk you through the numbers for your specific area.
Want to know exactly what solar would save on your bill? Send us a recent Synergy bill and we'll put together a free, no-obligation quote showing your projected savings, payback time and system design — tailored to your roof and usage. Call 9300 9324 or request a quote online at solaireconnect.com.au/get-a-quote.
References
Synergy. (2025). Standard Electricity Prices and Charges — South West Interconnected System. https://www.synergy.net.au
Synergy. (2025). Distributed Energy Buyback Scheme (DEBS) — Rates and Eligibility. https://www.synergy.net.au
Clean Energy Regulator. (2025). Small-scale Renewable Energy Scheme — Zone ratings and system output estimates. https://cer.gov.au
Government of Western Australia. (2025). Household electricity pricing. https://www.wa.gov.au/organisation/energy-policy-wa/household-electricity-pricing