Do you want to wow your guests with a truly unique, off-grid pool or spa experience? The weather is cooling down, and it's hard to imagine a better way to enjoy the Aussie outdoors in winter, than warming up in a wood fired spa.
A wood fired spa heater uses nothing but firewood to raise the temperature of your pool or spa water, runs completely off-grid, and costs a fraction of what gas and electric systems cost to operate.
This guide covers how wood fired pool heaters work, what size you need, how they compare to gas and electric alternatives, and whether this approach makes sense for your pool in Australian conditions.
How a Wood Fired Spa Heater Works
A wood fired spa heater is a standalone stainless steel unit that sits outside your pool. You connect it to the pool with two hoses — one draws cool water from the pool into the heater, the fire heats the water inside the heat exchanger, and the warm water flows back into the pool through the second hose.
The circulation happens through a thermosiphon, which is the natural movement of water caused by temperature differences. Hot water rises and cold water sinks, creating a continuous loop without any pump or power source. For pools where the heater sits more than 50 centimetres from the water, a low-pressure pump rated under 2,000 litres per hour can assist the flow.
The Winnerwell XL Wood Fired Pool Heater is purpose-built for this job. It handles pools up to 20,000 litres using AISI304 stainless steel construction and a large firebox designed for extended burn sessions.
What Size Pool Or Spa Can a Wood Fired Water Heater Handle
This is the first question most pool owners ask, and the answer depends on both the heater capacity and your expectations for heating time.
The Winnerwell L-size heater is rated for volumes up to 10,000 litres. That covers most hot tubs, plunge pools, and small above-ground pools. Expect to raise the temperature by 10 to 15 degrees over 3 to 5 hours of continuous burning.
The Winnerwell XL-size heater handles up to 20,000 litres, which covers larger above-ground pools and smaller in-ground pools. A standard 4 by 2.5 metre plunge pool holds around 10,000 to 12,000 litres, putting it well within the XL range.
For a full-size in-ground swimming pool of 40,000 to 60,000 litres, a single wood fired heater will not raise the temperature significantly in one session. Wood fired heaters work best on pools and tubs up to around 20,000 litres where you can get a meaningful temperature rise in an afternoon of burning.
Wood Fired vs Gas vs Electric vs Solar Spa Heating
Each pool heating method has strengths and trade-offs. Here is how they compare for Australian conditions.
Gas Spa Heaters
Gas heaters (natural gas or LPG) heat fast and work in any weather, but running costs are high. Expect $300 to $800 per month depending on pool size and usage. The unit itself costs $2,000 to $5,000 installed, and you need a gas connection. Gas heaters suit large pools that need rapid heating but the ongoing cost adds up fast.
Electric Heat Pumps
Electric heat pumps are the most popular choice in Australia. They cost $2,500 to $6,000 installed and run on household power. Operating costs are lower than gas at around $100 to $250 per month, but they heat slowly and struggle in cold ambient temperatures below 10 degrees. They also need a dedicated electrical circuit and professional installation.
Solar Pool Heating
Solar heating uses roof-mounted panels to warm pool water using sunlight. Installation runs $3,000 to $7,000 depending on roof space and pool size. Running costs are near zero, but solar only works during sunny hours and adds minimal heat in winter or overcast conditions. It cannot heat on demand.
Wood Fired Spa Heaters
A wood fired pool heater costs $1,849 to $2,229 for the unit with no installation cost beyond connecting two hoses. Running costs are $3 to $5 per session in firewood. It works in any weather, any time of day, and needs no electricity or gas connection. The trade-off is manual operation — you need to light and tend the fire for each heating session.
For off-grid properties, rural blocks, weekender cabins, and Airbnb setups where running gas or electrical infrastructure is expensive or impractical, wood fired is the most cost-effective pool heating option available.
Best Use Cases for a Wood Fired Spa Heater in Australia
Not every pool suits a wood fired heater. Here are the situations where it makes the most sense.
Off-grid and rural properties where running gas lines or upgrading electrical capacity is expensive or impossible. A wood fired heater needs nothing but firewood and water.
Holiday homes and Airbnb rentals where the pool is used seasonally rather than daily. The low upfront cost and zero ongoing fixed costs make wood fired ideal for intermittent use.
Plunge pools and small above-ground pools up to 20,000 litres where a single heater can raise the temperature meaningfully in one session.
Properties with easy access to firewood. If you live on acreage with fallen timber, your heating fuel is free. Even buying split hardwood, a session costs less than $5.
As a backup heater to extend your swim season when your solar panels are not producing enough heat during winter or overcast weeks.
How to Set Up a Wood Fired Spa Heater
Setting up a Winnerwell wood fired pool heater is straightforward and does not require a plumber or electrician.
Place the heater on a level, non-combustible surface like concrete pavers or compacted gravel. Keep it at least one metre from any combustible material including pool fencing, timber decking, and garden beds.
Connect the lower hose from the heater inlet to a point near the bottom of your pool. Connect the upper hose from the heater outlet to a point near the top of the pool. This height difference helps thermosiphon work naturally.
If the distance between the heater and pool is more than 50 centimetres, add a small submersible or inline pump. Keep the flow rate under 2,000 litres per hour to avoid back-pressure inside the heat exchanger.
Assemble the chimney sections and secure them. Fill the pool to normal level, then light the fire using dry kindling and gradually add larger hardwood pieces once the fire is established. Water temperature should begin rising within 30 to 45 minutes.
Wood Fired Spa Heater Specifications
The Winnerwell L-size heater features a 600mm by 800mm body, 380mm by 700mm firebox, 120mm chimney pipe, and weighs 37 kilograms. It suits hot tubs and pools up to 10,000 litres and is priced at $1,849.
The Winnerwell XL-size heater has a 700mm by 900mm body, 460mm by 760mm firebox, 120mm chimney pipe, and weighs 47 kilograms. It handles pools up to 20,000 litres and is priced at $2,229.
Both models are constructed from AISI304 stainless steel, the same grade used in food processing and marine applications. This gives excellent corrosion resistance for repeated exposure to heat cycling and pool water chemistry.
Where to Buy a Wood Fired Pool Heater in Australia
Ramped Up is an Australian stockist of the Winnerwell wood fired hot tub and pool water heater range. Both the L-size and XL-size models are available with fast shipping Australia wide.
If you are unsure which size suits your pool, contact the Ramped Up team for advice on matching the right heater to your water volume and setup.
