Frequently Asked Questions
What is Fireflow?
Fireflow is a precision-engineered stainless steel coil system that transforms any water-tight container into a beautifully simple wood-fired hot tub.
Light a fire within the coil and as the water heats, it naturally circulates back into your tub through a process called thermosyphon - no electricity, no pumps, no complex mechanics.
Just wood. Water. Fire. Flow.
How does it work?
Fireflow works using a natural principle called thermosyphon circulation.
As water inside the stainless steel coil heats, it becomes lighter and rises. Cooler water from the tub flows down into the coil to replace it. This continuous natural circulation gently moves water through the system without the need for pumps or power.
The result is steady, even heating powered entirely by fire and gravity.
Do I need electricity?
No.
Fireflow requires no electricity, no extension leads, and no running costs beyond wood.
It is fully off-grid.
Do I need a pump?
No.
The system is entirely passive and self-circulating. Once the fire is lit and the water begins heating, thermosyphon circulation does the work automatically.
What kind of tub can I use?
Any water-tight container can be converted, including:
- Galvanised stock tanks
- Inflatable drop-stitch tubs
- Ice bath barrels
- Custom-built timber tubs
- Metal troughs
As long as it holds water securely, Fireflow can heat it.
How long does it take to heat the water?
Heating time depends on:
- The size of your tub
- Starting water temperature
- Fire intensity
- Weather conditions
As a general guide:
- Smaller tubs (2-person) can heat in 1–2 hours
- Larger tubs (4–6 person) may take 2–4 hours
A well-managed fire makes a significant difference.
Is installation complicated?
No.
Installation is straightforward and requires only basic tools.
The Coil Kit includes all necessary fittings and connectors. You simply:
- Drill two holes in your tub
- Install the bulkhead fittings
- Connect the hoses
- Fill with water
- Light the fire
No wiring. No plumbing systems. No specialist installers required.
Is it safe?
When used correctly, Fireflow is safe and reliable.
Important safety principles:
- The tub must always be filled before lighting a fire
- Water must be able to circulate freely
- The system must remain open-vented (never sealed)
- Keep children supervised around open flames
Full safety guidance is provided with every system.
Can I use it off-grid or while camping?
Yes.
Fireflow is designed for both:
- Permanent garden setups
- Remote off-grid locations
- Camping and outdoor retreats
As long as you have water and wood, you can create heat - even in remote places.
What fuel can I use?
Seasoned hardwood is ideal (oak, ash, beech, birch).
Avoid:
- Treated timber
- Painted wood
- Composite materials
Clean, dry firewood produces the best heat and cleanest burn.
Does the coil rust?
Fireflow coils are made from high-quality stainless steel designed for outdoor durability and water exposure.
With normal care and storage, the system is built to last for many years.
Can I leave it outside permanently?
Yes, but we recommend:
- Covering the coil when not in use
- Draining water from hoses in freezing conditions
- Storing indoors during extended winter periods
Basic care extends lifespan significantly.
Is this cheaper than a traditional hot tub?
Yes — significantly.
Traditional electric hot tubs often cost:
- Thousands to purchase
- Hundreds per year in electricity
- Ongoing maintenance and servicing
Fireflow removes:
- Electrical installation
- Pump systems
- Heating elements
- Complex maintenance
The simplicity keeps both upfront and ongoing costs low.
What makes Fireflow different?
Fireflow focuses on:
- Mechanical simplicity
- Natural circulation
- Clean design
- Emotional experience
It’s not just a hot tub - it’s a slower, more intentional way to bathe outdoors.
No noise.
No humming pumps.
No control panels.
Just the sound of fire and moving water.
Do you offer different sizes?
Yes.
We offer:
- Coil Kits (for converting your own tub)
- Nomad 2 (2-person inflatable system)
- Nomad 6 (6-person inflatable system)
Each designed to work seamlessly with the Fireflow heating system.