Product Description
An immersed heater inside the hot tub
SubmergeFire™ 26 is a heater for a compatible hot tub, not a complete bathing product. Its body sits in the water, transferring heat directly rather than through a separate heater outside the tub and an external circulation loop.
This layout keeps the surrounding area clear, but the heater and its protective surround take up internal space. Check the tub geometry, benches, flue position and required guard before deciding that an internal heater suits your project.
Technical details
| Feature | Specification |
|---|---|
| Type | Internal, immersed wood-fired hot tub heater |
| Nominal output | 26 kW |
| Material | AISI 316 stainless steel |
| Plate thickness | 2–3 mm |
| Fuel | Wood only |
| Water circuit | Direct immersion; no separate external flow-and-return loop |
| UK delivery | London area included; contact us with a postcode for other UK locations, Scotland or Ireland |
View the SubmergeFire technical drawing for the heater body, feet, fixing arrangement and installation dimensions. Use the drawing to check the actual installation; do not estimate compatibility from a photograph.
What is supplied?
| Component | Supply status |
|---|---|
| Heater body and firebox lid | Included |
| Flue elements and rain cap | Included |
| Fixings | Included |
| Stainless-steel surround around the immersed body | Not included; make to suit the actual tub on site |
| Ash shovel | Separately priced UK option |
| Chimney guard | Separately priced UK option |
The body surround and chimney guard are different parts
The stainless-steel surround visible around the heater in some photographs is not a standard included part. Its shape depends on the tub and the space around the heater, so it needs to be designed and made for the actual installation. It is not normally supplied as a separate standard accessory.
The optional chimney guard protects against accidental contact near the flue. It does not replace the required protection around the immersed heater body. Confirm both arrangements before fitting the heater.
Why choose an internal layout?
Direct immersion avoids an external heater body and the associated exposed circulation hoses. This can be useful where space outside the tub is limited. The trade-off is less internal room: allow for the heater, guard, seating and access to the firebox together.
Compatibility and installation planning
This heater is not universally compatible with every tub. Check dimensions, fixing points, firebox access, chimney route and the custom surround against the actual shell and bench layout. The installation must provide practical access for loading wood, removing cooled ash and inspecting the heater.
Validate the applicable clearances and protection for the supplied heater and the site. The technical drawing and installation instructions take precedence over photographs when setting out the installation.
Fill before lighting and use wood only
Fill the tub to the required level before lighting the fire. Never operate the heater dry or without the specified water coverage. This is a wood-fired appliance; other fuels are not part of the documented use.
Output and heating time
A 26 kW nominal output does not establish a fixed heating time. Water volume, starting temperature, weather, wind, insulation, the cover, wood quality and how the fire is managed all affect the result. Plan around the actual tub and operating conditions rather than a universal promise in hours.
Water treatment and maintenance
The AISI 316 specification permits appropriate chlorine treatment within the supplied care instructions; salt treatment is not recommended. Let the heater cool before cleaning and keep the firebox, flue and surrounding area accessible for maintenance.
Is SubmergeFire™ 26 the right layout?
Choose this immersed 26 kW heater when keeping the outside area clear is important and the inside of the tub can accommodate both the heater and its custom protective surround.
If maximising bathing room is the priority, consider an external-heater layout instead. Confirm the drawing, mounting arrangement, protective surround and supplied parts before ordering.
Frequently asked questions
The selected configuration, final drawing and accepted order documents take precedence for the product supplied.
Is this a complete hot tub?
No. It is an internal heater for a compatible hot tub.
What are the output and material?
26 kW nominal output, with 2–3 mm AISI 316 stainless-steel construction.
How does it heat the water?
The immersed heater body transfers heat directly to the water. There is no separate external heater and flow-and-return pipe loop.
Does it take up room inside the tub?
Yes. Allow space for the heater body, the custom protective surround and a suitable bench and access layout.
Where can I check the dimensions?
View the SubmergeFire technical drawing provides the body and mounting details needed to assess the installation.
What is included?
The heater body, firebox lid, flue elements, rain cap and fixings. London-area delivery is included; other destinations need a postcode-based confirmation.
Is the stainless-steel body surround included?
No. It must be made to suit the actual tub on site and is not normally sold as a standard separate accessory. It is different from the optional chimney guard.
Which accessories are available in the UK?
An ash shovel and a metal chimney guard are separately priced options on this page.
Which fuel can I use?
Wood only, following the supplied operating instructions.
Can I use chlorine or salt treatment?
Appropriate chlorine treatment is permitted for the AISI 316 heater within its care instructions. Salt treatment is not recommended.
Must I fill the tub before lighting?
Yes. The heater must have the required water coverage before a fire is lit. Never operate it dry.
How long will heating take?
No single time is guaranteed. Water volume and starting temperature, weather, wind, insulation, cover, wood and firing conditions all matter.
What delivery is included?
The UK selector includes delivery to the London area. For other UK locations, Scotland or Ireland, contact us with the delivery postcode.
