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How to heat and maintain your wood fired hot tub? A simple step by step guide with tips and tricks.

Updated: Aug 15, 2022

A wood fired hot tub is an efficient and simple soaking tub which uses a wood burning stove instead of an electrical heater. They tend to have a circular barrel shape made of cedar wood. Due to the wood burning stove, the hot tub heats up significantly faster than a regular electric heater.

How to heat and maintain your wood fired hot tub? A simple step by step guide with tips and tricks
How to heat and maintain your wood fired hot tub? A simple step by step guide with tips and tricks

Wood burning hot tubs also don't require the use of any chemicals such as chlorine or bromine as they may affect the wood and/or stove, if you do decide to use chemicals, ensure you are using the right stainless steel grade stove as the standard grade stove is not suitable for chlorine or bromine, however there are chlorine free sanitiser products available from our showroom and online-store that are suitable for any type of wood burning hot tub.

What is the safest and best way at filling your wood fired hot tub with water?

Most people will unreal the garden hose, place the hose into the bottom of the wood fired hot tub, turn the water on and walk, however this is wrong as we will explain in the step by step guide;

  1. Unreal your garden hose and point the nozzle away from the hot tub and turn the water on allowing the water to flush out for several minutes. Why you ask? Your garden hose environment is ideal for the growth and interaction of Legionella and free-living amoebae (FLA) due to biofilm formation, elevated temperatures, and stagnation of water - by flushing the hose for several minutes, you are removing the stagnation of water prior to putting fresh clean water into your wood fired hot tub.

  2. Place the watering end of the hose at the top edge of your wood fired hot tub and secure the hose by placing it gently under the cover - Do not let the hose watering end fall under the waterline of the wood fired hot tub as this could cause back-siphoning of the water. Tip: Ideally, a non-return valve device should be fitted to the hosepipe or bib-tap.

  3. Check Water Level: The recommended water level for a wood burning hot tub is 10-20cm from the top of the hot tub, allow the hose to run and once the water reaches the recommended water level remove the hose and then place your floating thermometer into the water.

What type of firewood should I use to heat my wood fired hot tub?

Woodsure is the UK’s only woodfuel quality assurance scheme. The Woodsure website has a postcode search to help find your local firewood supplier. When purchasing firewood for immediate use always look for the Ready to Burn certification mark. This demonstrates that the moisture content of the firewood is no more than 20% and is ready to burn.

Tubmarine Stainless Steel Wood Fired Hot Tub on display at Penguin Spas Outdoor Living Showroom

To start the fire in the wood burning stove, which should only be done after the hot tub has been filled with fresh clean water to the optimal level, gather 12-25kg of dry seasoned wood within the recommended length of 25-30cm long in advance, make some pieces of wood small kindling pieces and some larger logs that are split into quarters or halves. To avoid smoke it's best to use kiln dried wood, barkless wood will also produce less smoke. Kiln dried wood will also allow the heating process to be sped up.

Tip: Combine softwood (e.g., pine, fir) with hardwood (oak, beech, etc.) in equal amounts for best heating results.

IMPORTANT: You must never use anything other than wood. Coal or charcoal used in the stove is likely to damage the system (due to much higher burning temperatures) and ruin future enjoyment of the wooden hot tub.

How do you light a wood burning hot tub fire?

Lighting a wood burning hot tub fire for the first time can sometimes be difficult and there are countless guides on the internet. Our team has pulled together the best guidance available so you can get it right first time.

There are two popular methods of lighting a fire:

  • Pyramid Method and

  • The Jenga Method

For both methods you will need a firelighter, kindling and your firewood. Use the appropriate safety gloves and equipment.

Traditional Method of Lighting a Fire

With the use of a firelighter and a small amount of kindling, a small amount of heat will be produced to warm the flue. Firelighters can be an easier method as they burn at a steady rate.

IMPORTANT: Do not burn paper. Paper burns very quickly and can easily float up the chimney. This is dangerous since flames that enter the chimney can ignite the creosote deposits in the flue. Furthermore, the hot air and pieces of burning paper can rise through the chimney and ignite flammable materials outside.

Traditional Lighting Steps

Place small pieces of dried kindling into a triangular shape over the Firestarter's, allowing for air gaps. Place two smallish logs on either side of the kindling to allow for larger logs to be placed over the well alight kindling. Ensure that the air controls are set to the manufacturer’s guidelines to make lighting as easy as possible.

The Pyramid Method of Lighting a Fire

The Pyramid method aids in the flue getting up to temperature more quickly and removes the need to open the wood fired hot tub door to add fuel to the kindling which means there is less of a chance of the combustion chamber cooling.

Once the well ignited kindling has burnt through, the flue shall be warm and the logs which the kindling has sat upon should now be charred and ignite cleanly.

Upside Down Lighting Steps

  1. Place two small logs across the fire bed.

  2. Place 5 pieces of kindling across the two logs, then 4 pieces laid at a 90-degree angle across the bottom layer and place two firelighters in between the gaps.

  3. Add another five pieces of kindling laid in the same direction as the bottom layer.

  4. Light the firelighters and close the door of the wood fire hot tub stove. The fire will slowly increase, warming the flue gradually without producing copious amounts of smoke and pollutants to the atmosphere.

  5. Set the air controls to the manufacturer’s settings.

  6. Leave the kindling well alone until the top of the appliance is warm and then close the primary air control, the kindling will fall between the logs. Once these are burning well the burn rate of the wood fired hot tub can be adjusted and more logs applied to the fire as required to heat the water.

The Jenga Method of Lighting a Fire

This technique involves criss-crossing layers of kindling at right angles, and involves much less balancing than the pyramid. Make sure to leave gaps between each piece of kindling, about the same width again, to promote airflow.

You can add logs on top of your kindling Jenga, although it’s also just as convenient to chuck them on once the smaller pieces have burned down.

How to test the water temperature of your wood fired hot tub safely?

When heating a wood burning hot tub, most users enjoy a hot tub temperature range between 36°C and 38°C, however, 40°C is the highest temperature that any wood fired hot tub should reach as exceeding 40°C is potentially harmful and should be avoided.

To reach your ideal bathing temperature as fast as possible it is recommended to turn the jets on for a few minutes or stir the water to circulate the water across the hot tub and check the temperature of the hot tub around every 15 to 20 minutes.

What do I do once the ideal bathing temperature of my wood fired hot tub has been reached?

When your ideal bathing temperature has reached (remember not to exceed 40°C) you are ready to use the wood burning hot tub, no further logs need to be added. Make sure to close the heater's air vents before you use the wood burning hot tub and if there is too much water, feel free to drain the desired amount out of the hot tub. If the water gets too hot it is a good idea to open the hot tub's lid for a while to let the water cool before you get into the hot tub or add some more cold water from the hose if there is enough space in the hot tub - use the drain valve if required.

How do you maintain a steady heat of water in your wood fired hot tub?

If the wood fired hot tub is being used for longer periods of time, the water temperature may drop slightly. A good way to maintain the heat of your wood burning hot tub is to place some larger hard wood logs into the stove of the hot tub, at this point the hard wood will burn for longer. Make sure air vents are open to keep the fire slow and steady due to the good air flow.

How do you empty and clean a wood burning hot tub?

Hygiene is one of the most important factors of having a wood fired hot tub especially if you have opted not to add any chemical, sanitisers, or filtration system. If you have purchased an off-grid wood fired hot tub, we would recommend draining the hot tub daily, but if you have purchased a wood fired hot tub with a filtration system, please read the manufacturers guidelines as there are so many different spa filtration systems on the market.

Once the water has cooled down, connect your hose to the water drain valve and disperse the grey water to a safe place – we would normally water our garden. Once emptied, use the garden hose (do not use a pressure washer), and spray the inside of the tub from top to bottom with fresh water which will help remove any debris (grass, sand, stone etc) – leave the drain tap open and allow the excess water in the pipes to drain out.

Once the wood fired hot tub has been hosed down, using a dry cloth, apply AquaSPArkle Spa Surface Cleaner (available from our online store) and gently work around the inside of the hot tub – this product will help remove any oils and grease marks. Once completed, close and secure the hot tub lid and get yourself a well-earned beverage or two.


What is the best wood fired hot tub to buy UK?

Buying a new wood fired hot tub is always an exciting experience, but there are so many options to choose from and can sometimes be difficult to narrow down the best wood fired hot tub for your needs. Penguin Spas is here to help. Our mission is to help you choose your perfect wood fired hot tub for you to enjoy and relax.

Traditional Wood Fired Hot Tubs

Traditional Wood Fired Hot Tubs

Choose the very best from our range of traditional Scandinavian wood fired hot tubs that have been designed to be simple and timeless with an elemental everlasting design.

Fiberglass Wood Fired Hot Tubs

Fiberglass Wood Fired Hot Tubs

Choose from our exclusive premium collection of BaltoScandia eco-friendly handcrafted luxury fiberglass wood fired hot tubs with Scandinavian Thermowood cladding.

Stainless Steel Wood Fired Hot Tubs

Stainless Steel Wood Fired Hot Tubs

View our beautifully UK designed stainless steel wood fired hot tubs. Our range of Stainless-steel hot tubs are eco-friendly in the environment and green by their nature.

Plunge Cold Tubs and Ice Tub

Plunge Cold Tubs

Cold water and ice therapy with our plunge tub. After enjoying the hot tub or sauna, many bathers will quickly cool themselves down by getting into a cold plunge pool or ice bath.

Accessories for your wood fired hot tub


Make your wood fired hot tub experience more pleasurable with our large range of accessories including hydrotherapy jets, sand filtration system, salts, and chemicals.


About Penguin Spas Premium Outdoor Living

Here at Penguin Spa Premium Outdoor Living, we are passionate about delivering the best quality hot tubs, best in energy efficiency, great value for money, and unbeatable customer service. Our friendly team is here to help you choose the right hot tub for your needs and your budget.

Award Winning Penguin Spas Premium Outdoor Living Showroom - Scotland
Award Winning Penguin Spas Premium Outdoor Living Showroom - Scotland

Our new Scottish outdoor living showroom is an oasis of calm, showcasing a large selection of multiple award-winning hot tubs, wood fired hot tubs and accessories we have to offer. Based in Yieldshields, near Carluke – right in the central belt of Scotland – we are within easy reach of the M74 & M8 motorway network and less than 35-minute drive to the city of Edinburgh and Glasgow.

Since 2012, Penguin Spas Outdoor Living have been devoted at creating and supplying elaborate products which are all designed to help improve people’s health, wellbeing, wellness, and happiness.

All our premium products are carefully designed and manufactured, and we strive to constantly improve ourselves and the products we deliver. We embrace new technologies and understand the importance of delivering reliable and durable products which help to improve our customers lives.

Do you want to know more about our range of multiple award-winning, energy efficient hot tubs available here in Scotland?

Here at Penguin Spas, we are proud to be the only official Scottish dealer of award-winning, energy efficiency gold standard hot tubs and swim spas from UK designed Sunbeach Spas and the world’s premier spa brand Oasis Spas

Both manufacturers of the Sunbeach Spas and the Oasis Spas have created a complete insulation energy saving system that reduces energy consumption to save you money. You can have peace of mind that your hot tub or swim spa will be hot and ready for you, without costly energy bills.

Sunbeach Spas are leading the hot tub and swim spa industry with energy efficient SmartSpa™ R10 insulation and cutting edge technology. The multiple award-winning Sunbeach Spas are all designed here in the UK and are manufactured with the newest industry features which the company consistently pushes the industry forward with innovative designs and features.

Eco Spas are committed at improving the wellbeing of people and the health of our planet. Eco Spas is proud to be at the forefront of energy efficiency hot tub design and manufacture. Each of our holiday park hot tubs have been carefully designed here in the UK in compliance with current safety guidance written by the Health and Safety Executive (HSG282) which provides constant efficiency and immediate use while ensuring utmost hygiene and guaranteeing the easiest maintenance possible resulting in an experience that becomes an asset to your business.

Oasis Spas are built by one of the world’s largest international hot tub and swim spa manufacturers who distribute products in 40 countries around the world. Oasis Spas are built to last with premium components and the thickest shells on the market. The Power Saver Technology with SmartSpa+™ R10 insulation will save you thousands over the life of your hot tub or swim spa and the Easy-Care Technology makes maintenance simple.


Wood Fired Hot Tubs

We know a lot of thought and research goes into buying a hot tub and if you have not already seen a wood fired hot tub, we would strongly encourage you to come to our new outdoor living showroom where you can view the European Product Design Award Hot Tub from Tubmarine and a range of BaltoScandia wood-fired hot tubs.

Tubmarine: Since 2013,Tubmarine founder Chris Galley has worked with the engineers and suppliers throughout the UK and Europe to arrive at the new hot tub design. The end result is a hot tub that requires absolutely no electricity, heats up in less than two hours and is easy to maintain.

BaltoScandia Wood-Fired Hot Tubs: BaltoScandia is on a mission to bring a practical, aesthetic Scandinavian lifestyle to every garden across the UK. Our hot tubs, saunas, and cabins are manufactured with great care and workmanship at a competitive price point, without compromising on quality.


Outdoor Living Premium Range

As our company has grown so has our passion to create amazing outdoor spaces. Whatever style garden you have, large or small, you want it to be a place that you can relax in, and escape to. As well as the obvious perks of getting more fresh air and sunlight, there are lots of other benefits of an ideal outdoor living spaces.

Creating an outdoor living space will provide an additional space in your home to relax and unwind. Expand the space that you already have available to you. A casual living space in the garden is also the perfect place to entertain guests, to provide seating, and mingling space to enjoy evening drinks or a BBQ. Create a functional and enjoyable area for you and your family to use in the garden, whatever the weather.

BaltoScandia is a family-owned company founded with a clear objective: to create and design a premium line of Scandinavian designed outdoor living products like no other. There collection of premium Scandinavian designed cosy BBQ huts, grill cabins, glamping pods, glamping cubes, sauna cabins, sauna barrels and hot tub enclosures are all designed for private, and business uses.

Alfa Forni Pizza Ovens - Everybody Loves Restaurant Quality Pizza. Now You Can Enjoy it at Home with an Alfa Oven! Turning a traditional tool like an oven into a designer object acclaimed all over the world as a standard-bearer for “Made in Italy” and high-quality has always been the mission of the Alfa family. That is why Alfa ovens are conceived and designed as professional ovens that guarantee excellent results in baking pizza, bread and then some combined with unparalleled ease of use and maintenance.

The story of RB73 is a story of passion for fire. But also of beautiful and timeless products. Handmade by professionals with love for the product. Enjoy beautiful moments, enjoy staying outside! Think of warm summer evenings, but also throughout the rest of the year there are often beautiful days when an outdoor fireplace can be used to give that wonderful extra warmth and atmosphere on your terrace. The fires have glass fronted doors so you do not suffer from smoke, ash or sparks on the terrace.

Contact Us

Address: Thornhome House, Yieldshields, Carluke, South Lanarkshire, Scotland, ML8 4QD

Telephone: 0800 112 3886 or 01555 729 607


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