How to read your smart meter data in Western Australia

Your smart meter quietly records your electricity use every 30 minutes. Over a year that builds a detailed picture of exactly when your household draws power and how much. Most people never look at it. That's a shame, because it's the best map you have for cutting your bill.

What a smart meter actually does

Western Power has been rolling smart meters across the SWIS (South West Interconnected System) since 2015. An old accumulation meter only knew one thing: the total since it was last read. A smart meter knows far more:

• Interval data — your usage in 30-minute blocks
• Import and export — what you buy from the grid and, if you have solar, what you send back
• Peak demand — the highest draw you hit at any moment
• Voltage and power quality — the technical health of your supply

Getting hold of your data

Through your My Synergy account

1. Log in to My Synergy
2. Open "My Usage"
3. Look at the daily, weekly, or monthly consumption charts
4. Download the CSV if you want to dig into the detail yourself

Through Western Power directly

For the full interval record:

1. Go to the Western Power website
2. Request your interval data (an NMI data request)
3. You'll get it in NEM12 format (CSV)
4. It covers up to two years of history

Through your inverter app

Already have solar? Your inverter app (Fronius, SolarEdge, Enphase, and the rest) shows generation and consumption in close to real time.

Reading your usage pattern

The daily load profile

A typical Perth household's day tends to follow a shape like this:

• 6am–8am: morning spike (hot water, kettle, heating)
• 8am–3pm: quieter, with the house at work and school
• 3pm–6pm: everyone's home again (cooking, AC, screens)
• 6pm–9pm: the evening peak (cooking, laundry, TV, lights)
• 9pm–6am: overnight baseload (fridge, standby, hot water)

What to look for

Your baseload. This is the floor your overnight usage never drops below. An efficient home sits around 300–500W. If yours runs higher, the usual suspects are:

• a tired fridge or freezer
• standby power vampires (old TVs, gaming consoles)
• a pool pump running overnight
• hot water heating at the wrong time

Peak spikes. Sudden sharp jumps usually point to:

• air conditioning kicking in
• the electric oven or cooktop
• a hot water system boosting
• a pool or bore pump

Solar against usage. With solar, lay your generation curve over your usage curve. The gap between them tells the story:

• generation above usage: you're exporting and earning credits
• usage above generation: you're importing and paying the full rate
• the overlap: self-consumption, and that's the most valuable kWh you have

Turning interval data into savings

Spot a better tariff

Your interval data shows whether a time-of-use plan would suit you. Work out three things:

1. your peak usage (3pm–9pm weekdays)
2. your off-peak usage (overnight and weekends)
3. your midday usage (the cheap solar window)

If most of your power lands outside the peak window, a time-of-use plan like Midday Saver could pay off. Our Savings Planner will model it against your real numbers.

Hunt down the energy vampires

Look at your overnight baseload between 1am and 4am. That's your true minimum. If it's sitting above 500W, switch appliances off one at a time across a few nights and watch which one moves the floor. The usual culprits:

• a second fridge in the garage (100–200W, around the clock)
• a pool pump running overnight (1,000–2,000W)
• a hot water system heating at expensive times
• old ducted AC idling in standby

Make the most of your own solar

Put your generation curve next to your usage curve and shift what you can into the sunny hours:

1. move flexible loads into the solar peak (roughly 10am–2pm)
2. set the hot water to heat while the sun's up
3. run the pool pump at peak generation
4. pre-cool the house in the afternoon before generation tails off

Every kWh you use yourself instead of exporting is worth around 25–30c. That's the gap between the A1 import rate you'd otherwise pay (32.37c/kWh, rising to ~33.26c from 1 July 2026) and the DEBS buyback you'd earn for exporting it (2c/kWh off-peak, 10c/kWh in the 3pm–9pm window). Self-consumption wins almost every time.

Size a battery from real numbers

Interval data is the honest way to size a battery:

1. evening import (3pm–midnight): this is what a battery needs to cover
2. midday excess solar (10am–3pm): this is what charges it
3. match the two: a battery that soaks up your spare solar and carries you through the evening gives the cleanest payback

In our modelled Perth scenarios a 10–13kWh battery suits most households, though the WA Battery Scheme rebate caps at 10kWh ($130/kWh, max $1,300, Synergy customers). Going much larger rarely improves the maths unless you have a big solar system or unusually heavy evening use. Run your own figures in the Savings Planner before you commit.

Making sense of NEM12 data

Download the raw interval data and it arrives as NEM12. The structure is simpler than it looks:

• 200 rows hold the metadata (NMI, meter serial, and so on)
• 300 rows hold the actual interval readings
• each 300 row carries 48 readings, one per 30-minute block
• quality flags mark whether a reading is actual, estimated, or substituted

You can open a NEM12 file in Excel and squint at it. Or you can let a tool like BillWise read it and draw the patterns for you.

Common profiles and what they tell you

The "camel hump." Two peaks, morning and evening, with a midday dip. This is the classic working-household-without-solar shape.

The "flat line." Steady use all day. That points to always-on loads, or a home that's busy from morning to night.

The "reverse peak." Heavy midday, light evening. You see this when electric hot water heats during the day. It's a great fit for the Midday Saver tariff.

The "cliff edge." A sharp drop at a set time, usually a timer-controlled pool pump or hot water system clicking off.

Take a look with BillWise

Upload your Synergy bill or interval data and BillWise will:

• draw your consumption patterns
• show your biggest cost drivers
• suggest the tariff that fits your profile
• model battery and solar sizing
• list the specific moves that lower your bill

Get your personalised analysis →

Your meter has been keeping a diary of your energy life this whole time. Learning to read it is where taking back control of your bill begins.

Want to see what your meter data means for solar? Try our Savings Planner to model different tariff and solar combinations, or upload your bill for a detailed breakdown of your usage patterns.