The blog

The maths behind your power bill.

Running costs, paybacks and head-to-heads — in plain English, with the numbers shown. Is it worth it? We do the sums so you don’t have to.

Topics: Benchmarks Bills Business EV Explainer Grants Heating & cooling Hot water Is it worth it Lighting Quick wins Running costs Solar

AU Running costs

What's the cheapest way to cool a room? Fans, portables and splits priced per hour (Australia)

A ceiling fan costs about 2c an hour. A portable air conditioner costs about 36c — for less cooling than a small split delivers at 18c. Every common way to cool a room, priced per hour, plus the combination that beats them all.

24 Sept 2026 Read →

AU Heating & cooling

What size air conditioner do you need? The honest kW guide for Australia

The same 30 m² room needs a 1.8 kW air conditioner in Hobart, 2.3 kW in Sydney, 2.6 kW in Brisbane — yet generic size guides recommend 3.5–5 kW. How to size a split or ducted system properly, with the free industry calculator installers use.

2 Sept 2026 Read →

AU Heating & cooling

Ducted air conditioning installation cost in Australia (2026): prices by home size, changeover and rebates

Installation prices for ducted reverse-cycle in Australia: $8,000–20,000 for most homes, $8,000–14,000 for a changeover that reuses your ducts, and the state rebates — including Victoria's, which gets harder from 30 September. What actually moves the number.

28 Aug 2026 Read →

AU Business

What's a demand charge? The half-hour that sets your business power bill

Some business tariffs bill you for your single hungriest half-hour of the month — and from 1 September, NSW retailers must ask before putting you on one. How the charge works, what it costs, and the fix that's a sequence, not a spend.

23 Aug 2026 Read →

AU Explainer

Peak and off-peak electricity times in Australia (2026) — every network, every state, one table

When is off-peak electricity? It depends on your network and your retailer — and they often disagree. Every Australian network's 2026 peak and off-peak hours, state by state, in one table; the big retailers' windows beside them; and the cheap window that has quietly moved to the middle of the day almost everywhere.

23 Aug 2026 Read →

AU Explainer

Paying peak power rates all year? Your network only charges them for 8 months

Since July 2024, Ausgrid's peak window only exists in summer and winter — but fewer than half of energy retailers pass that on. Here's the two-minute check, worth about $100 a year.

18 Aug 2026 Read →

AU Explainer

Petrol just jumped 30c a litre — what can you actually do about it?

The fuel excise is back at full rate, and the war premium never left. Here's how an energy manager thinks about a household's transport bill — security first, cost second, and a two-car answer most advice misses.

14 Aug 2026 Read →

AU Is it worth it

Should you buy a home battery before the rebate shrinks?

The federal battery discount is real, and really shrinking — installers know it. Here's what the rebate is actually worth, what a battery honestly earns, and who should genuinely hurry.

13 Aug 2026 Read →

AU Is it worth it

EV vs hybrid vs petrol: the honest mid-size SUV maths for Australia

Same hour-by-hour model as our hatchback study, opposite answer: for mid-size SUVs the hybrid wins — for now. Here's the honest maths, and exactly when the EV catches up.

10 Aug 2026 Read →

AU Is it worth it

EV vs petrol vs hybrid: the honest hatchback maths for Australia

The cheapest hatchback to own in Australia is now electric. We modelled a real household hour by hour to prove it — here's the honest maths, and the fine print.

2 Aug 2026 Read →

NZ Running costs

What's the cheapest way to heat a room in New Zealand? (priced per hour)

A 2kW panel heater costs about 74c an hour to run. The same warmth from a heat pump costs roughly 19c. Every common Kiwi heater priced per hour of warmth — including the LPG cabinet heater you should retire.

19 July 2026 Read →

AU Quick wins

Draught-proofing: the $30 heating upgrade (Australia)

Sealing gaps around doors, windows and floorboards can cut heating and cooling loads by 10–20% — for the price of a takeaway dinner. Where the leaks hide, how to find them, and what to buy.

19 July 2026 Read →

NZ Quick wins

Your hot water cylinder is about 30% of your power bill — four cheap fixes (NZ)

Hot water is the quiet giant of the Kiwi power bill. Check your tariff, your thermostat, your cylinder wrap and your showers — most homes can claw back real money without replacing anything.

19 July 2026 Read →

AU Running costs

What's the cheapest way to heat a room? (Australia, priced per hour)

A bar heater costs about 72c an hour. The same warmth from a reverse-cycle split costs about 17c. Here's every common heater priced per hour of warmth — and the catches worth knowing.

5 July 2026 Read →

UK Is it worth it

The price cap just rose 13% — should you fix your energy tariff?

The Ofgem cap hit £1,663 on 1 July, but it only bites if you're on a variable tariff — and 60% of households are. Here's the fix-or-wait decision explained honestly, with the numbers.

5 July 2026 Read →

AU Is it worth it

Is heat-pump hot water worth it? The payback maths

A heat-pump hot water system cuts water-heating energy by 70–75% and saves a typical Australian home about $500 a year. Whether it's worth it depends on one thing — when you buy it. Here's the honest working.

5 July 2026 Read →

UK Bills

What's a normal energy bill in the UK? (by home size)

Ofgem's "typical" household pays £1,663 a year at the July cap — but that's a 3-bed semi. Here's what normal looks like for your home size, what an efficient home pays, and how to tell which you are.

5 July 2026 Read →

NZ Bills

What's the average power bill in New Zealand? (by household size)

The average Kiwi home uses about 7,100 kWh a year — but "normal" swings hugely with household size and whether you're in Auckland or Invercargill. Here are the benchmarks, and the efficient number worth aiming at.

5 July 2026 Read →

NZ Grants

EECA's Warmer Kiwi Homes grants in 2026: you might be eligible now (even if you weren't last year)

EECA's insulation and heating grant quietly expanded to middle-income areas in January — 50,000+ more households qualify and most don't know. Here's who's eligible, what's covered, what changed, and what it's worth.

5 July 2026 Read →

AU Is it worth it

The Solar Sharer Offer: 3 free hours a day — but is the whole plan cheaper?

From 1 July, retailers in NSW, SE QLD and SA must offer a plan with 3 hours of free midday electricity. Who actually comes out ahead, what to shift into the window, and the one comparison that matters.

5 July 2026 Read →

AU Bills

What's the average power bill for your household size? (Australia)

Regulator benchmark data puts the average 4-person east-coast home at roughly $2,850 a year for electricity — about $700 a quarter. Here are the average bills by household size, what an efficient home pays, and how to tell if yours is high.

4 July 2026 Read →

AU Bills

Power prices just fell — so why is your winter bill higher?

Default electricity offers dropped on 1 July in most states, yet winter bills are landing hundreds of dollars up. Three things changed at once — here's what they are and what's worth doing about each.

4 July 2026 Read →

AU Is it worth it

Are LED downlights worth switching to? The payback maths

Swapping 10 halogen downlights for LEDs saves a typical Australian home about $220 a year — and the changeover usually pays for itself inside a year. Here’s the working.

28 June 2026 Read →

AU Is it worth it

Is rooftop solar worth it in Australia? Payback explained

A 6.6kW rooftop solar system pays back in about 5 years in Australia — the sweet spot. Here’s the honest maths on savings, feed-in tariffs, and why a battery is a different decision.

24 June 2026 Read →

AU Running costs

How much does it cost to run ducted air conditioning in Australia?

Ducted reverse-cycle aircon costs a typical Australian home about $600–1,200 a year to run. Here’s the maths — and why replacing a working system to save energy rarely pays back.

18 June 2026 Read →