top of page

How to choose, order, and install HUUM sauna stoves & WiFi sauna controllers


1. Introduction to HUUM

2. The Story of HUUM

3. How to choose your HUUM wood-fired stove or electric heater

3.1. Calculate the kW output power you will need to heat your sauna (electric & wood-fired) 3.2. Measure your sauna safety distance requirements (electric & wood-fired)

3.3. Investigate your sauna wiring and input power (electric only)

3.4. Choose your stones (electric & wood-fired) and air tunnel (electric Hive online)

3.5. Choose your UKU sauna control system (electric only)

4. How to order​ HUUM products in the UK

4.1. Confirm your order

4.2. Pay your invoice

4.3. R​eceive your HUUM delivery

5. How to install an electric HUUM sauna stove and UKU sauna control system

5.1. How to install an electric HUUM sauna stove

5.2. How to install an UKU sauna control system with a WiFi, GSM, or local connection

5.3. How to place the stones into the heater

6. Final questions to consider when buying a sauna stove from an online retailer

6.1. Check what’s included

6.2. Beware of non-transparent sellers

1. Introduction to HUUM

HUUM combines ancient sauna building principles with contemporary Nordic design and cutting-edge technology.

Their electric heaters and wood-fired stoves don’t just look good in the sauna, but are carefully designed with minimal metal to hold a large number of stones that provide the best possible heat and steam.

HUUM has also designed a smart control system called UKU for electric heaters, which includes a wall-mounted controller and a mobile app so you can control your sauna with improved safety and convenience from anywhere — like while travelling home or out exercising.

Here at Estonian Saunas, we’ve delivered HUUM sauna stoves and UKU sauna control systems

to a wide range of customers across Britain from luxury spas to pop-up beach saunas, from country estates to small apartments, and even an English Premier League football club, which has it alongside their training pitch (we’re just not allowed to say which one!) We also work closely with quality sauna builders who are helping others fulfill the dream of owning a home sauna.

2. The story of HUUM

The founder of HUUM, Siim Nellis, comes from a family of sauna stove builders over several generations in Estonia.

Following years of technical development, Nellis turned to the Estonian Academy of Arts in 2011 and challenged students there to help design a more efficient electric sauna heater that combines traditional Estonian sauna building knowledge with modern design and smart technology. They decided that modern sauna stoves are too industrial and that the design focus should be returned to the stones, as it has been for thousands of years, which provides a superior heat and steam.

The winning design was the Drop, a wall-mounted electric stove inspired by the shape of a water droplet.

Despite taking up very little space in the sauna, the Drop design holds 55kg of stones, which is far more than many wood-burning stoves. After further development, the Drop was launched in 2014 and immediately received positive feedback from sauna enthusiasts, as well as several design awards.

As a result, HUUM has continued to grow and invest in further product development, including the UKU smart control system that would provide sauna users with added convenience and safety.

The company established its primary presence in Tartu, the academic and cultural heart of Estonia, but it also relies on skilled expertise from metal workers across Estonia who individually work on different elements of the production, much of which is too creative for automated process lines so it requires handwork.

Their second design was Hive, a larger free-standing stove that is available as both an electric and wood-fired version. This was launched in 2016 and has already proved popular in public saunas and spas, as well as larger home saunas.

The technology has evolved too, including the HUUM mobile app which is under continuous development. This was originally only controlled through an inbuilt SIM card that requires a connection fee, but HUUM then launched their WiFi-connected UKU controllers at the start of 2019.

As for us, we created our own business, Estonian Saunas, to help export Estonian sauna design, technology, and traditions — which is why we’ve enjoyed a long and close relationship with HUUM.

We installed the first WiFi-connected sauna stove at our own home in Tallinn​ and have been exporting them ever since. We also invested in HUUM ourselves to support their expansion.

We are also currently developing another sauna with a HUUM wood-fired stove — although this one is inside a ZiL-131 Soviet Army truck!

At the end of 2019, HUUM launched two new heater designs, Steel and Cliff, with smaller safety distances and lower power input requirements in response to the growing demand for home saunas — especially in smaller spaces such as apartments.

​Demand for HUUM sauna stoves and WiFi controllers has surged in 2020 as more people spend more time at home and thinking about their health. After global lockdowns began, total HUUM sales increased more than three times in March. However, this is merely an acceleration of existing trends as more people invest in home saunas, which is something that is already normal in our part of the world. Fortunately, the production is relatively small scale and spaced out already so it is able to continue safely.

The biggest issue has merely been sourcing enough stones to meet the increased demand.

3. How to choose your HUUM wood-fired stove or electric heater​

As mentioned, there are now four main types of HUUM stoves.

Drop is an elegant wall-mounted stove in the shape of a drop. Hive is a curvaceous free-standing stove for larger saunas. Cliff and Steel are both upright stoves with shorter safety distances suited for smaller saunas. They are all available as electric heaters, while Hive is also available as a wood-fired stove that can be heated either in the hot room or through the wall from the next room.

You are welcome to download the manuals for all these stoves in advance, which contains more detailed information about specifications and safety distances. Here they are: Drop, Hive, Cliff, Steel.

There are five steps here to understand when choosing a HUUM stove:

  1. Calculate the kW output power you will need to heat your sauna (electric & wood-fired)

  2. Measure your sauna safety distance requirements (electric & wood-fired)

  3. Investigate your sauna wiring and input power (electric only)

  4. Choose your stones (electric & wood-fired) and air tunnel (electric Hive online)

  5. Choose your UKU sauna control system (electric only)

3.1. Calculate the kW output power you will need to heat your sauna (electric and wood-fired)

This first part is for both electric heaters and wood-fired stoves. You’ll need to determine how much output power you’ll need from your sauna heater or stove in order to heat your sauna hot room properly.

HUUM heaters and stoves can be used in sauna hot rooms ranging from 3 to 35 cubic metres in size. The output power is measured in kW (for both electric heaters and wood-fired stoves).

As a very general rule, you will need about 1 kW of power for every 1 cubic metre of room that you are heating, although slightly more if you have more non-insulated surfaces (like windows and a glass door) or if you have more heat-storing surfaces (like brick, concrete or large logs) You’ll also need slightly more power output if you are using a wood-fired stove.

Most modern sauna hot rooms are built to a fairly standard style, however, with almost all wooden surfaces and one glass door. Based on that, this table shows what output power can comfortably heat what size of room:

Electric sauna heaters

3.5 kW: 3 to 6 cubic metres

4.5 kW: 3 to 7 cubic metres

6 kW: 5 to 10 cubic metres

9 kW: 8 to 15 cubic metres

10.5 kW: 10 to 17 cubic metres

12 kW: 12 to 25 cubic metres

15 kW: 15 to 30 cubic metres

18 kW: 18 to 35 cubic metres

Wood-fired sauna stoves

13 kW: 6 to 13 cubic metres

17 kW: 8 to 16 cubic metres

If you have any doubts about the power you’ll need then HUUM has also a great sauna calculator on their website here.

3.2. Understand your sauna safety distances (electric and wood-fired)

Your stove must be placed at minimum distances from any combustible surfaces. More detailed information is available in the product guides for each stove here: Drop, Hive, Cliff, and Steel.

In this guide, we’re not going into details about sauna construction as we are focused on the stoves, but you do at least need to ensure that the construction of your sauna meets these minimum safety distances.

Here is an overview of them for every HUUM stove based on type and kW size:


Drop 4.5 kW A: 100 mm B: 590 mm C: 435 mm

Drop 6 kW A: 120 mm B: 630 mm C: 455 mm

Drop 9 kW A: 150 mm B: 690 mm C: 485 mm

HIVE (electric)

Hive 6 kW​ A: 60 mm B: 580 mm

Hive 9 kW​ A: 90 mm B: 640 mm

Hive 12 kW​ A: 120 mm B: 800 mm

Hive 15 kW​ A: 150 mm B: 860 mm

Hive 18 kW​ A: 180 mm B: 920 mm


Cliff 3.5 kW​ A: 60 mm B: 390 mm

Cliff 6 kW​ A: 60 mm B: 390 mm

Cliff 9 kW​ A: 120 mm B: 510 mm

Cliff 10.5 kW​ A: 180 mm B: 920 mm


Steel 3.5 kW​ A: 50 mm B: 420 mm

Steel 6 kW​ A: 60 mm B: 390 mm

Steel 9 kW​ A: 100 mm B: 520 mm

Steel 10.5 kW​ A: 100 mm B: 520 mm

Hive (wood-fired)

Hive wood-fired 13 kW​ A: 250 mm B: 900 mm

Steel 17 kW​ A: 500 mm B: 1000 mm

Steel 17 kW LS (through the wall heating)​ A: 500 mm B: 1000 mm

3.3. Understand your sauna wiring and input power (electric only)

If you are planning an electric sauna then you’ll next need to know the power of your main fuse to ensure it matches the input power required for the heater. You also need to know whether you have 1-phase or 3-phase wiring.

If you have 1-phase, which is standard in UK homes but also found elsewhere in Europe, then you’ll need to choose a HUUM sauna heater that has up to 9 kW output power. If you have 3-phase wiring, which is standard in UK commercial premises and most places across Europe, then you can choose any HUUM sauna heater.

As it happens, when we built our own first sauna with a HUUM heater, we had an apartment with single phase wiring that couldn’t even handle the kettle and washing machine being on at the same time! However, we were able to upgrade from 1-phase to 3-phase fairly easily so that is also an option if you need more power.

If you have any doubt at all about the correct wiring for your property, check your electricity bill or box — or speak directly to your electricity provider. And always use a certified electrician for any electrical installation.

3.4. Choose your sauna stones (electric and wood-fired) and Hive air tunnel (electric Hive only)

​This step doesn’t actually apply to our online shop at because we include all stones and an air tunnel as standard.

HUUM stones are carefully selected grey rounded volcanic stones gathered in Finland and known as olivine dolerite in British English or olivine diabase in American English. These stones are recommended for HUUM stoves for both their visual aesthetic as well as the quality of the heat and steam that they produce.

In addition, if you choose an electric Hive stove then you have the option of adding an air tunnel. This is inserted into the mechanism to increase air circulation among the stones, which helps care for the stove and also improve the quality of the sauna experience. If you do add an air tunnel then this reduces the number of stones you will need.

So here are the quantities of stones required to fill each HUUM stove:

  • Drop electric stoves (all): 60 kg of 5 to 10 cm diameter stones.

  • Hive electric stoves (6 & 9 kW) without air tunnel: 120 kg of 10 to 15 cm diameter stones and 30 kg of 5 to 10 cm diameter stones.

  • Hive electric stoves (6 & 9 kW) with air tunnel: 80 kg of 10 to 15 cm diameter stones and 30 kg of 5 to 10 cm diameter stones.

  • Hive electric stoves (12, 15 & 18 kW) without air tunnel: 220 kg of 10 to 15 cm diameter stones and 30 kg of 5 to 10 cm diameter stones.

  • Hive electric stoves (12, 15 & 18 kW) with air tunnel: 180 kg of 10 to 15 cm diameter stones and 30 kg of 5 to 10 cm diameter stones.

  • Hive wood-burning stoves (13 kW): 90 kg of 5 to 10 cm stones.

  • Hive wood-burning stoves (17 kW): 100 kg of 10 to 15 cm stones and 30 kg of 5 to 10 cm stones.

3.4. Choose your UKU control system (electric only)

If you have chosen an electric stove then you’ll also need a control system for it. For this, HUUM has developed UKU.

The UKU sauna control system by HUUM include a wall-mounted controller, which is placed outside the sauna, and available in a range of colours. That colour is your first decision. We provide a black wall-mounted controller as standard, but you can pay slightly more for one in white, sand, metallic, olive, or wood.

Your second choice is how the control system is connected. There are three options: a local connection, a GSM connection (though a mobile network with an with a embedded SIM) or a WiFi connection (which we recommend and has no annual fee).

If you choose to have a GSM or WiFi-connected sauna then you will also have access to the HUUM mobile app, which includes the same controls as the wall-mounted controller and is being continuously developed with new features. Both the wall-mounted UKU controller and the app will enable you to not just switch your sauna on and off, but also see the current temperature, choose your target temperature, and set a timer. The control system also includes safety features, including an automatic stove shutdown for overheating or when the door is open.

4. How to order​ HUUM products across Europe

  1. Confirm your order

  2. Pay your invoice

  3. R​eceive your HUUM delivery

4.1. Confirm your order

Visit and select your HUUM products. Or simply send us an email at The prices in our online store exclude VAT.

By the way, we only use the information you submit at this stage to deliver your order then check back with you once in future by e-mail to see how happy you are with your sauna. We don’t give anyone else your data or use it for any future marketing.​ Our entire marketing strategy is basically just to make content for sauna enthusiasts that’s genuinely interesting so we don’t bother with email marketing and all that stuff.

4.2. Pay your invoice

If you’ve selected payment by invoice then we will issue an invoice to either you or your company so you can make the payment directly to our UK bank account, which is with TransferWise. You are also welcome to use TransferWise to pay into our Estonian bank account. We don't take card payments because we like to keep costs as low as possible for customers (and most of our customers are businesses that want to pay by invoice anyway) but if you use TransferWise service to send money to our Estonian bank account then that is one way you can pay by card.

Once the payment is received, we’ll dispatch the order as fast as possible.

​​Fun fact: TransferWise is also a British-Estonian company like us and they have a sauna with a HUUM stove in their London office! The company was created by former employees of Skype, which yes was also an Estonian company! You can read more about the saunas of TransferWise on our blog here. They started by offering a cross-border money transfer services but now offer international banking too, which is why it is so easy for us to accept payments in different countries.

4.3. Receive your HUUM delivery

We always use reliable couriers and add insurance to the delivery. So if anything goes wrong with your products on the way to you then you can trust us to fix it as fast as possible. That’s very rare though.

We’ll pass on any specific delivery instructions to the courier and also give you the tracking number so you can see when it’s arriving. The delivery driver will have your phone number in case there are any issues on arrival finding you. That’s the only reason we ask for your phone number when you order.

5. How to install an electric HUUM sauna stove and UKU sauna control system

We worked with HUUM to make these videos for them about how to set up an an electric stove with an UKU sauna control system, and also how to add the stones. This is based on a Drop stove, but the principles are the same for other electric stoves.

Our most important bit of advice here is to always use a qualified electrician for the installation of electric home products like this. Most electricians should find the process fairly straight forward but you can show them these videos if they have any issues (and you can also email us at for additional questions).

First, here’s how to install the Drop electric stove:

And here’s how to install the UKU sauna control system by HUUM and connect it to the Drop stove:

And here’s how to place all the stones inside the Drop heater:

Oh… and don’t forget to send us pictures of your sauna! We love sharing them on our @estoniansaunas social media accounts. They are inspiring to other sauna enthusiasts and also loved by Estonians who want to see where Estonian sauna design and technology ends up around the world.

6. Final questions to consider when buying a sauna stove from an online retailer

6.1. Check what’s included

Most sauna stove retailers sell all items separately. A stove might look like a great price, but you’d need to buy the stones and the control system separately. And those stones certainly add to the shipping cost!

We believe in selling the stove and the stones together to give a clearer price. We don’t mind providing a special quote to someone who wants to use their own stones (and even put together this guide for collecting sauna stones), but in our experience this is rarely the case. HUUM has already selected the optimal type of stone, which is then polished and rounded to compliment the overall look of the stove and supplied at good value-for-money.

Like everyone else though, we do sell the UKU sauna control systems separately because there are different options for the type of system and also the colour of the wall-mounted controller. Also, you can combine stoves and control systems from different manufacturers.

6.2. Beware of nontransparent sellers

As saunas increase in popularity, so too do the range of online sellers and the potential for things to go wrong.

HUUM products are very high quality so customers have rarely had any problems after receiving them. They all come with warranties too. We’ve had occasional mishaps with deliveries, but we’ve always fixed any issues as fast as we can.

The best way to assure customers is by being as transparent as possible. You should expect any online seller to clearly display the legal name of their company and where it is registered. This is good business practice and a basic courtesy to customers who should be able to conduct due diligence on who they are ordering from. In fact, it's a legal requirement in a lot of countries too even though too many online retailers ignore the law. At the very least, customers should also be able to verify that info on official state business registries.

We go much further. In fact, our founder Adam's previous life was working for the Estonian government to help support the development of our transparent, trusted business environment. We continue to speak out publicly about the importance of this for improving trust in business. We believe transparency is good for everyone: legitimate entrepreneurs, consumers (especially online), and wider society.

So here’s some things you might want to know about us:

Our business is an Estonian company, registered in Estonia as Estonian Saunas OÜ (LTD). Our registry code is 12986006 and our VAT number is EE101870812. The owners and directors are Adam Rang and Anni Oviir. We’re both Estonians, although Adam is also a dual citizen of the UK.

Our company’s legal address is Veskiposti 2-1002, Tallinn, 10138, Estonia. We’ve got no office because we have a very lean operation.

On top of all this, a lot of data about our company is publicly available, including financial information and things like how much tax we pay. And all public data about Estonian companies, including everything mentioned above, is verified by our state through the use of our secure digital identities.

We try to keep our business as lean as possible and our prices as fair as possible so we would be surprised if anyone is able to beat us in the UK on value for money sauna stoves. However, let us know if you see anything different.

Thanks for reading

If you are ready, you can choose your HUUM products to be delivered to you in the UK through us at

You can also just send us an email at We get a lot of emails that begin ‘Hi Tere’, but tere is actually just ‘hi’ in Estonian! Anni or Adam will reply to you as soon as we can.

We really enjoy helping more people enjoy good saunas so we export not just Estonian sauna design and technology, but also our traditions as much as possible too! If you’d like to learn more and follow our own adventures, you can check out the rest of this Estonian Saunas blog or follow us on Instagram, Facebook, YouTube and Twitter. We also have a Facebook group for Sauna Builders & Explorers.

bottom of page