Wattcalc articles
Plain-English explainers on Australian energy and sustainability decisions. Every article is researched against primary government and regulator sources, links back to the calculator that does the maths, and is reviewed monthly to keep figures current.
Why we publish
Australian residential energy decisions are deceptively complex. The maths on rooftop solar has flipped twice in the last decade — once when feed-in tariffs collapsed, again as retail rates climbed past 30 c/kWh. The federal Cheaper Home Batteries program (May 2026, $258 per kWh tier 1) has rewritten battery payback. EV running costs depend on whether you charge from solar, off-peak or a public DC fast charger. Heat-pump hot water is now eligible for federal STCs and state schemes like VEU and ESS — but only if you pick the right model. Time-of-use tariffs save some households hundreds and cost others hundreds.
The articles below exist to translate the regulator publications and program documentation into plain English, anchor everything in 2025–26 numbers, and connect each topic back to the Wattcalc calculator that runs the maths for your specific household. We don't sell solar systems, EVs, batteries, hot water systems or electricity plans, and we don't earn a commission from anyone who does. Read the editorial principles on our About page.
Solar & rooftop systems
Whether solar is worth it, what size to install, what feed-in tariff you can realistically expect, and how the federal STC rebate actually works — the building-block topics for any rooftop solar decision.
Is solar worth it in Australia in 2026?
Feed-in tariffs have collapsed since 2018 — but retail electricity rates haven't. Here's what payback actually looks like in 2026 with worked examples.
Read article →6.6 kW, 10 kW or 13 kW solar: which size for your home?
The biggest system isn't always the best. A 2026 guide to right-sizing solar based on usage, roof, export limits and self-consumption.
Read article →Solar feed-in tariffs by state in 2026
FiT rates vary widely by state and retailer. Here's the 2026 picture for NSW, VIC, QLD, SA, WA, TAS, ACT and NT — with the highest-paying retailers in each market.
Read article →Solar and battery rebates by state in 2026
Federal STCs apply nationally, but each state layers its own incentives. What's available in 2026 — and which schemes are about to close.
Read article →How STCs work: Australia's solar rebate, explained
STCs are netted off your install price by the installer — there's no separate rebate to claim. Here's what they're worth, why they're falling, and what to watch.
Read article →Home batteries & VPPs
The federal Cheaper Home Batteries rebate has changed the maths in 2026. Whether a battery is right for your household depends on your evening usage, feed-in tariff, and whether VPP membership stacks up.
Should I get a battery with my solar in 2026?
The federal Cheaper Home Batteries rebate ($258/kWh tier 1) changed the maths. Here's when a battery pays back, when it doesn't, and what to model first.
Read article →VPPs explained: are they worth joining?
Virtual Power Plants let your battery support the grid in exchange for credits or upfront discounts. Which Australian VPPs actually pay, and what to watch.
Read article →Tariffs, bills & electricity prices
Decoding your electricity bill, choosing between time-of-use and flat rates, and understanding what households actually pay in your state.
How to reduce your electricity bill (2025–26)
The highest-impact, lowest-effort moves Australian households can make in 2025–26 — from tariff swaps to load shifting and small efficiency wins.
Read article →Time-of-use vs flat-rate electricity: which is cheaper?
ToU tariffs split your day into peak/shoulder/off-peak. Whether they save you money depends entirely on when you use power. A 2026 guide with worked examples.
Read article →Average electricity prices by state in 2026
What households actually pay per kWh varies by 12c between states. The 2026 picture, plus what's driving prices in each market.
Read article →How to read your Australian electricity bill
Past usage, supply charges, GreenPower, controlled load — what every line on your bill actually means and how to spot a bad deal.
Read article →Electric vehicles & home charging
Whether an EV pencils out against petrol, what it actually costs to charge at home, and how to navigate Australian charger types and home install costs.
EV vs petrol Australia: the real cost breakdown
Sticker price is only part of it. We compare 10-year fuel, electricity and servicing costs for an EV against an equivalent petrol car using current Australian numbers.
Read article →How much does it cost to charge an EV at home in 2026?
Home charging costs $4–$15 per 'tank' depending on your tariff and solar setup — a fraction of petrol. The 2026 maths.
Read article →EV home charger types explained
Australian EV home chargers come in 3.6 kW to 22 kW flavours. What each level means, what fits your home, and what they cost in 2026.
Read article →Hot water & heat pumps
Heat-pump hot water is the cheapest way to make hot water in Australia in 2026 — if you pick the right model and qualify for the right rebates.
Editorial cadence
Wattcalc publishes one substantive article each week. Topics are picked from a continuously refreshed backlog that prioritises (1) high-intent decision-stage queries Australian households are searching for in Search Console, (2) state-specific variants of common questions where the answer differs by state, and (3) explainers that close gaps between primary regulator publications and what households can actually do with the information. Every article is reviewed monthly against an automated audit of 11 federal and state primary sources — if a rebate, tariff or scheme changes, the affected article is updated and the "last reviewed" date is bumped.
Have a topic suggestion? Get in touch.