The Wood-Fired Hot Tub Buyer’s Guide


If you’re looking for a wood-fired hot tub, you’d be forgiven for feeling overwhelmed at the options available at first glance.

There is a wide range of customisations and features available for these peaceful retreats, each adding to their ease of use, convenience, appearance, or experience.

This article gives an overview of the options available to buyers, and will help you decide what you’d like your own wood-fired hot tub experience to look like.

We’re going to consider 5 factors in the selection process when buying a wooden hot tub:

Types of Wood-Fired Hot Tub

Wood-fired hot tubs can be categorised into 4 types:

  • Fibreglass Hot Tubs
  • Lined (or Polypropylene) Tubs
  • Wooden Hot tubs
  • Ofuro Hot Tubs

While each of these works the same way; with a wood-fired stove heating the bathing water within the hot tub, the type of tub you choose will make all the difference to your delightful wood-fired tubbing experience.

Let’s take a look at each type of wooden hot tub, and talk about the differences…

Fibreglass Wood-Fired Hot Tubs

Often described as the most luxurious wooden hot tubs, Fibreglass lined hot tubs comprise a shaped liner sat within the wooden facade of the tub.

Thanks to the superior structural properties of fibreglass these liners are ergonomically shaped, making them exceptionally comfortable.  This strength also makes fibreglass lined hot tubs the only type of tub suitable for use with an integrated external heater; the stylish centrepiece fire that is the signature feature of these tubs.  The liner is moulded around a heater set within the timber hot tub exterior, allowing easy access and a sharp, clean appearance to the final installation.

Lined Wood-Fired Hot Tubs

Polypropylene lined hot tubs are the “middle ground” between a traditional wood-fired hot tub and a fibreglass-lined hot tub.

The wooden exterior of the hot tub is fitted internally with a resistant, recycled plastic liner, separating the timber exterior from the bathing water.  This allows the use of chemicals to maintain water hygiene for longer, extending the time between drain downs and cleaning.  

The interior finish also makes it very easy to clean a lined tub – no scrubbing is required; the interior can simply be wiped down.

Traditional Wooden Hot Tubs

Crafted from natural timber, traditional wooden hot tubs provide a simple way to enjoy fresh air and relaxing warm water.  

A wood-fired internal or external heater delivers warmth directly to the bathing water.  Supported by wooden benches within the tub, bathers sit deeper and can enjoy the unencumbered simplicity of the experience.

Well suited to back-to-nature retreats and natural gardens, traditional wooden hot tubs are made to similar designs as were first conceived hundreds of years ago.  Their appeal tends to lie in their budget-friendly cost and rustic charm.  

Ofuro Hot Tubs

Unlike the types of wood fired hot tubs above, Ofuro refers to the shape of the wooden hot tub.  

Originally crafted by the Japanese as a luxurious deep soaking bath and often dubbed “Love Tubs” for their intimate nature, Ofuro are instantly recognisable thanks to their oval shape.

The key feature of Ofuro Hot Tubs is that they’re suitable for 1 or 2 people only to use at one time.  This makes them popular for couples and holiday retreats, but not for larger gatherings.

Wooden Hot Tub Sizing

Wood-fired hot tubs are available in a wide range  of sizes, from personal Ofuro hot  tubs designed to give two people an intimate bathing experience, to 2.2m polypropylene lined hot tubs that can accommodate 10-12 people at once.

When you’re deciding the best size hot tub for your garden, the first question to answer at first is simply “how many people will you be sharing with?”.

The size of your new wooden hot tub will dictate how many people you can share with at once.

If your new tub is going to transform your garden into the party capital of the street, and you’re expecting to regularly host guests as well as your own family you’ll need to ensure that your tub  can comfortably accommodate everyone (there’s nothing worse than waiting in the chilly air for someone to hop out so you can take their place!).

Wood-fired hot tubs are available in sizes suitable for seating up to 12 people, with the smaller Ofuro Tubs only suitable for 2 bathers at once.

Big=Best?

Before you plump for the biggest tub you can fit with visions of floating around on an inflatable unicorn, larger-than-necessary tubs do have some drawbacks.

For one, larger tubs hold more water which means they’re going to take longer to drain down for cleaning, and longer to fill afterwards.  

It’s also worth remembering that a larger tub will take longer to heat up, and will need a few extra logs to reach temperature.  Although the difference isn’t huge, if you light the stove when you get in from work, a larger tub could mean the difference between hopping in at 8.30pm instead of 7pm.

For context, a 2.2m wooden hot tub (10-12 people) holds 2,700 litres, while a 1.6m tub (4-6 people) has a 1,400 litre capacity.  That’s almost twice as much water in the larger tub, and hence almost twice as long to wait for it to get toasty after lighting the fire!

Water Capacity

When discussing size, it’s worth noting that not all types of wooden hot tub carry the same capacity of water.

Traditional wood-fired hot tubs, and lined hot tubs hold more water than a fibreglass hot tub.

The fiberglass liner is shaped within the hot tub exterior to provide more comfortable, ergonomic seating shaped to support you in the water.  This reduces the water capacity, because the liner does not fill the full interior space within the tub.  

Where an external integrated heater is fitted to a fibreglass tub, the liner is shaped around the stove, further reducing the water capacity.  Internal Heaters sit within the bathing area and also reduce the hot tub’s water capacity.

Location

Your wooden hot tub should be sited with clear access at all sides, for periodic inspection, maintenance and staining/painting of the exterior (if desired).  

Wood-fired hot tubs all have a chimney from the stove (no matter which heater type you choose), which needs to vent safely and can get hot.  

Access will be required for loading and cleaning the heater, so it’s important to remember this when positioning the tub.  Having to squeeze through a tight gap to load logs into the stove will quickly make the process something you dread, and take the shine off your anticipation of using it!

Although the space in position is a key consideration, an often-overlooked aspect is the access available between the delivery drop off, and final position.  Window sills, waste pipes and fence posts have all hampered Royal Tubs’ deliveries in the past, and we can’t stress the importance of a quick check with a tape measure before you order, to make sure your tub is able to reach its new home. 

Sizing Takeaway

Your perfect hot tub will be large enough to accomodate the guests you’re expecting, while fitting comfortably into its surroundings and dovetailing with your lifestyle.

Wood-Fired Hot Tub Accessories

Not all of the accessories available are compatible with each tub type; please check the comparison table below to see if your wood-fired tub is suitable.  

Fibreglass Lined Traditional
Drain Valve
Chimney Guard
Air Bubbles x x
Lights ✓ (fewer options available)
Massage Jets x x
Skimatic Filter
External Filter x
Stirring Paddle
Matching Steps
Decorative Rim x
Drinks Holder

While many add-ons can be considered “luxuries”, there are some which make all the difference to living with your wood-fired hot tub.  The importance and convenience of these can’t be understated.

Essentials

Drain Valve

A drain tap is a simple modification to your tub, allowing it to be drained via a simple lever valve.  

Where most wooden hot tubs have a “bung” positioned at the bottom of the tub (much like a bath plug), adding a drain valve extends this drain beneath the tub to a manual valve fitted externally.  This lets the owner easily connect the drain to a hose, and empty the water for cleaning without having to get in the tub.  

Chimney Guard

The chimney guard wraps around the flue pipe, giving valuable clearance between the hot chimney and any rogue legs or fingers that might brush past.  This greatly reduces the chance of burns from contact with the chimney.

Insulated Lid

Although every wood-fired tub *should* come with a lid, these tend to be designed only to prevent leaves, bugs and other debris finding their way into your spa.  

An insulated lid keeps the heat in your tub for longer, meaning it heats up faster the next time you want to use it.  

Enrich The Experience

Massage Jets

Embedded into the walls of your tub, massage jets are operated at the flick of a switch and comprise pumped jets of water to ease muscle tension and provide an added dimension to your soak.

Air Bubble Systems

Air bubble systems deliver jets of air from beneath your tub, creating the sensation of being massaged.  

Unlike massage jets which pump water to work out muscle tension, air bubbles provide a gentler impression, bolstering the feeling of tranquil relaxation.  

Lights

While they’re a seemingly simple addition, adding lights into the walls or floor of your tub can transform your hot tub into an otherworldly escape, creating a nighttime atmosphere far removed from your usual back garden experience.

Convenience

Some accessories just make your tub simple to live with.  Although these don’t have the same “sexiness” as light and jets, these add-ons will make maintenance and use a breeze, letting you cut out the hassle between lighting up and jumping in.

Filters

There are two filters types suited to use with a wood-fired tub:

Skimatic Filters

A schematic filter sits on the edge of the hot tub, and can be used with any tub type without needing a power supply.  It catches floating debris and traps it, removing leaves, bugs and other bits and pieces that find their way in from the surface of the tub.

External Filters 

External filters are connected through the wall of the hot tub, pumping the water through either sand or fibreballs to decontaminate it and extend the time between drain downs for cleaning.

Stirring Paddles

A simple addition to your tub; a stirring paddle lets you ensure the water in your wooden hot tub is evenly heated to give accurate temperature readings before hopping in.

Appearance

Matching Steps

Crafted from the same timber as your wooden hot tub’s exterior, a set of matching steps adds functional value in keeping with the look and feel of your tub, making access effortless.

Drinks Holder

Designed to be in keeping with the tone of your tub, with a drinks holder lets you safely store your glasses without fear of stray elbows. 

Adding accessories is by no means needed to enjoy your new tub.  By taking a moment to consider how you’ll live with your tub and the memories you hope to create there, you might just find a little something to add another dimension to your blissful retreat.

For a more detailed look at the benefits of adding accessories to your wood-fired hot tub, you can read our dedicated blog: Wood-Fired Hot Tub Accessories – Are They Worth Adding?

Wood Fired Hot Tub Exterior Upgrades

Some exterior options will make it easier to live with your tub, or let it sit seamlessly into its new surroundings.  Others will save you time and money. 

We’re looking at Accessories that compliment the exterior of your wood-fired hot tub, and the options for customising its look.

Exterior Cladding

The exterior cladding on your wood-fired tub is most of what you’ll see day-to-day, while your tub isn’t in use.

If your tub is going to be on show (and why wouldn’t it be?!) then being able to match your hot tub’s cladding to its surroundings lets your tub sit seamlessly into its surroundings.

Exterior timber cladding is available in Larch, Western Red Cedar, Oak, Spruce and Thermowood.

Spruce is a budget friendly, standard option for our wood -fired hot tubs.  Robust and light in colour, it often has a knotty finish giving it a distinct character.  Perfectly suited to traditional wood-fired hot tubs, spruce should be stained or painted to protect it from the elements.

Western Red Cedar is a favourite cladding timber among architects and designers, commonly used in home building.  It’s distinctive reddish colour lasts well over time, and it’s exceptionally durable, resistant to moisture and decay.  Staining for longevity is recommended, but you wouldn’t want to paint over its gorgeous colour.  This timber is often chosen to accompany our fibreglass or lined hot tubs.

Oak is synonymous with English Character.  Hard-wearing, dense and resistant to decay, it weathers to a striking silvery tone with time, although many customers prefer to stain the timber to show off its characteristic grain.

Larch is another budget-friendly timber, perfectly suited to traditional wooden hot tubs.  Resistant to attack by insects and rot, larch also weathers to a distinctive grey colour although we recommend staining to protect it from the weather and preserve its pale, natural colour.

Thermowood gives a striking coloured finish, as well as boasting exceptional durability and resistance to warping.  Commonly added to fibreglass lined tubs, Thermowood is naturally heat treated before fitting to prolong its life and give prominence to its rich colouring.

Lid  

The basic function of the hot tub lid is to keep out debris but upgrading has its benefits.

A fibreglass lid lets you match your lid to your hot tub’s liner, giving a pleasing aesthetic finish.  Fibreglass lids are also lighter than their wooden counterparts, making them easier to remove and replace.

Insulated lids slow the rate at which your hot tub cools down after use meaning your tub will heat up faster the next day, and also reduces the number of logs needed to bring it back up to perfect bathing temperature.  

Steps

Steps aren’t a necessity, they make your tub far easier to live with and because they can be made to match your tub’s exterior, they fit seamlessly into your install.  

Steps also serve to guide access in and out of your tub, saving you from marshalling guests and preventing the area around your tub getting soaked when it’s time to hop in and out. 

Decorative Rim

Sitting atop the timber facade, the rim gives a “meatier” appearance to the tub, concealing the depth of the timber slats as well as protecting the open grain.  

Heater Type

The type of heater you choose with your wood-fired hot tub will have an aesthetic impact alongside the exterior choice you make.

Weather/Exposure

If you’re planning on siting your tub under cover, or in a  concealed position, it’ll benefit from natural protection from the elements.  In the Irish climate this will give you more options for when you can enjoy your tub.

If the final position of your tub is likely to be exposed to the elements, it’s worth investing in a more durable timber option to prolong its appearance and protect it from the compounding effects of exposure.

Your Garden

Many customers like to match the exterior of their tub to the garden features around it, especially when installed on decking, next to fencing or your house itself.

By previewing the timber finishes you can choose a tub to complement your garden, or even select other materials to match your tub if you’re planning on further additions later on.

Exterior Summary

Wood-fired hot tubs are a striking addition to a garden and by customising the exterior to match its surroundings and add extra functionality, you can ensure that your tub is just as joyful to look at as it is to use.

Wood-Fired Hot Tub Heater Options

Often confused with the tub type, the wood-fired stove is a customisable feature.  

Wood-fired stoves for hot tubs can be categorised into 3 types:

  • External Integrated
  • External 
  • Interal 

External Integrated Heaters

Fitted into the exterior of the tub itself, the stove is accessed through an external door to the firebox, for loading and lighting the fire, as well as emptying the ash periodically.

External Integrated Heaters are only available for use with fibreglass wooden hot tubs.

External Heaters

An external heater sits outside of the hot tub itself, positioned alongside the tub.  

The heater is connected to the bathing water via two hoses for inlet and outlet, and the heat is transferred by gravitation of convection currents.

External heaters are the only option available for Ofuro hot tubs, due to limited space inside the tub on account of their shape.  

Internal Heaters

Internal heaters are installed within the bathing area of a wood-fired hot tub, separated by a wooden fence.  They are loaded from above, and tend to be the most budget-friendly heater option.

A Note On Chimneys

All wood-fired stoves need a chimney to vent the smoke from the fire heating your tub.  It’s important to ensure that users are protected from burns arising from contact with the flue; chimney guards are an optional accessory to greatly reduce the chance of injury from contact with the hot metal.

Steel Choices:  Should You Upgrade?

All of our standard stoves are manufactured from 430 grade stainless steel.  This is a higher grade than many of our competitors use however it boasts strong anti-corrosive properties and will reliably last a long time.

Royal Tubs also offer heater upgrades to 304 and 316-grade stainless steel.

304-grade stainless steel has corrosion resistance, although the cost of the material increases because of this.  The outcome is a longer lasting stove, at the cost of a higher purchase price.

316-grade stainless steel has superior corrosion resistance, especially from acids and chlorides.  

To summarise:

430 grade is a resistant, high quality stainless steel grade used as standard in our heaters.

304 -grade has superior corrosion resistance in comparison to 430.

316-grade stainless steel is more resistant than 304 and 430-grade, especially against corrosion from chlorides.

The steel grade is particularly relevant to wood-fired hot tubs where chemicals are going to be used in the water.

Using Chemicals in the Water

Standard 430 grade steel is not suitable for the use of chemicals in the water.  304 and 316-grade stainless steel offer corrosion resistance, which allows for the use of chemicals, with 316 grade being the longest lasting under these conditions.  If you plan to use chemicals in the water, the heater must be upgraded to accommodate this.

What To Consider When Choosing Your Heater Type

These factors will determine the best heater choice for you.

Location & Accessibility

Your new wood-fired hot tub’s surroundings will play a part in choosing the best type of stove.

  • If your wood-fired tub is going to sit into an alcove, recess or corner, access in and out of the tub is going to be restricted to one or two sides of the tub.  In this case, an internal or external integrated heater would be the better option.
  • If your tub is going to sit in an open area, with free access around it an external heater would free up space within the hot tub itself and make cleaning and lighting easier.
  • In a rural garden an internal heater means that the exterior timber facade of the hot tub gives a natural appearance.
  • Where a wood-fired hot tub is installed for use by paying guests, such as a holiday let or glamping site, an integrated external heater is usually preferred as their inset fitting makes the chance of contact injuries very low.

Type of Wood-Fired Hot Tub

Fibreglass wood-fired hot tubs are the only models suitable for use with an external integrated heater.   

External heaters are also commonly used with fibreglass hot tubs, to free up additional space within the bathing area for more guests while maintaining the benefits of the shaped liner for comfort and convenience.

Internal heaters are commonly chosen for use with Traditional wooden hot tubs.  This combination is the most budget-friendly of the tub/heater pairings.

Both external and internal heaters can be used with poly-lined wood-fired hot tubs.  As with traditional wooden tubs, internal heaters tend to be favoured on cost grounds while external heaters are easy to access for cleaning and lighting.

Access

While internal heaters have many benefits, they tend to be slightly more awkward to clean as everything has to be done from above.  

External heaters can be positioned freely away from the tub to ensure clear access all around for inspection, and keep the fire door easily accessible for both loading and lighting the fire as well as cleaning the ash when required.  

Only available for use with fibreglass wood-fired hot tubs, external integrated heaters give easy access for lighting and cleaning is very easy, with everything carried out from directly in front of the heater.

Heater Choice Summary

While considerations such as positioning are crucial in making sure your new wood-fired hot tub can be used safely and easily, the most important factor is choosing a heater that’s suitable for your budget and your garden, with access playing a key role in your decision.

Using Chemicals in the Water

Standard 430 grade steel is not suitable for the use of chemicals in the water.  

304 and 316-grade stainless steel offer corrosion resistance, which allows for the use of chemicals, with 316 grade being the longest lasting under these conditions.  

If you plan to use chemicals in the water, the heater must be upgraded to accommodate this.

This post should have given you a basic overview of the factors to consider when buying a wood-fired hot tub. More detailed discussions on each topic can be found in the linked articles at the end of each section.

Whatever you decide, we’re sure your new wooden hot tub is going to bring you happy memories for many years to come.

If you still have questions, you’re welcome to contact us by phone, email or on Facebook and a member of our team will be happy to help.




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