By Sarah Chen · environmental engineer · water, waste and everything that flows downhill
“After my solar tank froze solid in a Canberra winter, I learned that off-grid heat demands twice the storage I originally planned.”
— Sarah. Every litre accounted for.
ArticlesCalculatorsSite PlannerShopOff-grid water heating in Australia runs on 4 main options: solar thermal, heat pump, wood stove or gas, with solar kits starting from $1200 AUD. Freezing tanks drop usable hot water fast, so storage should be sized at 2x daily use. Pick the fuel you already have on site.
You're off-grid in Australia. You've got the solar panels, the batteries, the composting toilet. But hot water? If you're using a gas bottle or a dodgy electric heater, you're wasting money and energy. Here's the real deal on the four main off-grid water heating options.
You're off-grid in Australia. You've got the solar panels, the batteries, the composting toilet. But hot water? If you're using a gas bottle or a dodgy electric heater, you're wasting money and energy. Here's the real deal on the four main off-grid water heating options.
How it works: Sun heats fluid in panels on your roof, transfers to a water tank. No electricity needed. Works in Aussie sun like a dream.
Pros: Zero running costs after install, reliable for 15+ years, perfect for our climate. You'll never pay for hot water again.
Cons: Upfront cost. Needs roof space. Not great in heavy rain (but Australia's mostly sunny).
Price: $2,500–$5,000 for a 150–200L system (1–2 person setup). Don't buy cheap Chinese panels—they'll crap out in 2 years.
Suppliers: Solar Thermal Australia (solarthermal.com.au) – full systems. Suntec (suntec.com.au) – good for residential. Tip: Get a 200L tank. 150L is a waste of money for off-grid.
How it works: Uses ambient air to heat water (like a fridge backwards). Needs 240V and battery backup for off-grid.
Pros: 70% less electricity than electric heaters. Works in cooler weather (Tasmania, alpine areas).
Cons: Needs a battery bank ($500–$1,000 extra), not great in extreme cold, expensive to install.
Price: $2,000–$4,000 (plus $500–$1,000 for battery backup). Not worth it unless you're in a cold spot.
Suppliers: Heat Pump Water Heaters (heatpumpwaterheaters.com.au) – off-grid models. Tip: Skip if you're in Queensland or NSW. Solar thermal is cheaper and simpler.
How it works: Wood stove with a heat exchanger heats water in a tank. Not just a regular wood stove.
Pros: Uses free fuel (if you've got wood), works when the sun's not shining, great for cold nights.
Cons: Requires constant wood chopping, fire risk, messy, and you need a proper heat exchanger (not a $300 "kit" from Bunnings).
Price: $1,500–$3,500 for a full system (stove + tank + exchanger).
Suppliers: Wood Stove World (woodstoveworld.com.au) – they do off-grid kits. Tip: If you're not chopping wood daily, skip this. It's a pain and a fire hazard.
How it works: Burns gas bottles to heat water. Easy to set up, but that's where the "easy" ends.
Pros: Quick to install. Works anywhere.
Cons: Propane is expensive ($100–$200/month for 2 people), requires refilling bottles (a pain), fire risk, and you're reliant on supply chains. If you're off-grid, you're already fighting the system—why add this?
Price: $500–$1,500 for the heater, but $100–$200/month for gas.
Suppliers: Gasworks (gasworks.com.au) – but don't bother. Tip: If you're using propane for off-grid, you're doing it wrong. It's a money pit.
| Method | Upfront Cost | Running Cost | Best For | Why You'll Regret It |
|---|---|---|---|---|
| Solar Thermal | $2,500–$5,000 | $0 | Most Aussies (sunbelt) | None. If you do it right, it's perfect. |
| Heat Pump | $2,500–$5,000 | Low (needs battery) | Cold climates (Tasmania, highlands) | Waste of money if you're not in a cold spot. |
| Wood Stove | $1,500–$3,500 | Low (wood) | Wood lots + no hassle tolerance | Fire risk, messy, and you'll hate it after 3 months. |
| Propane | $500–$1,500 | $100–$200/month | Short-term camping | Waste of money. You'll be paying for gas bottles for years. |
Practical Tip #1: Solar thermal is the only option that makes sense for off-grid in Australia. It's not cheap upfront, but it'll save you thousands over 15 years. Skip the "cheap" solar thermal systems—they're a scam.
Practical Tip #2: If you go solar thermal, get a 200L tank. 150L is for city dwellers. You'll be cold in winter if you don't.
Practical Tip #3: Never use propane for off-grid living. It's a waste of money and energy. If you're paying for gas bottles, you're doing it wrong.
Look, if you're off-grid in Australia, solar thermal is the only sensible option. It's not cheap upfront, but it's the most reliable, cheapest long-term solution. Propane? A waste of money. Wood stove? Only if you've got a woodlot and don't mind the hassle. Heat pump? Only if you're in Tasmania. But solar thermal? That's the one. Get it done right, and you'll have hot water for the next 15 years without a second thought. Stop wasting money on the wrong system. Do it right the first time.
Worth a watch: Stunning Off-Grid Home Setup | Genius Hot Water System That Never Runs Out! · Farm Learning with Tim Thompson
While many off-grid projects are achievable as DIY, certain situations require licensed professionals:
Always check local regulations and obtain necessary permits before commencing work.