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Product Detail

Aito Kiuas AK47, AK57 & AK57K Heat Storing Wood Burning Sauna/Banya Heater

£ 2,119.00 GBP

Product Description

AK stands for Aito Kiuas, which is Finnish for ‘Genuine Stove’. The sauna heater bears this name, because these traditional heat storing sauna stoves are based on the original sauna heaters used throughout the last century in Finland. Naturally the design has come a long way, being perfected by decades of Finnish ingenuity. Unlike the other constantly burning heaters, these legendary heat storing stoves require only a single heating to provide excellent sauna until the following morning. The huge stone capacity delivers exactly the right kind of high oxygen heat for the truest löyly which is easily regulated, even by a sauna novice.

The enamelled steel finish is the perfect choice for a durable heater, ensuring rust resistance and making is a pleasure to clean. This heater comes with extremely durable, fast-heating stones that extend their usage life and decrease the required heating time. The AK stoves are the top class heaters for the true sauna connoisseur. A fact that has lead the Finnish president, Sauli Niinistö, to choose this heater for his personal sauna. Needless to say, their constant heat supply is an excellent bonus when fitting sauna around his busy schedule.

The heat storing heater works by combining the high specific heat capacity of the large volume of olivine or ceramic stones with an insulated casing. In line with our Endurance ethos, the heater is protected with enamelled rustproof steel, the stone compartment is lined with fireproof bricks and the firebox made from cast elements and fireproof mass. Furthermore, the inner lid, fire-grate and hatch are made from high quality cast iron. The AK-47 and 57 heaters are also available as tunnel model heaters, which is truly the ideal option for the user who insists on a tranquil sauna experience. The AK-57 is also available with a white enamel coating.

The heaters require durable ceramic stones sauna stones due the high heats within the heaters. Both the AK57 and AK57 are available with heater tunnels that allow the heater to be fueled from the outside of the sauna room through the wall. These can be purchased separately here. The AK57 is also available with a extension piece that makes the heater taller (AK57K modification), which is particularly useful where the sauna or banya has raised or mezzanine benching. The AK57K also considerably increases the heaters stone capacity for a further improved löyly. The AK57K extension piece can be purchased here along with the additional ceramic stones required.

Product Specification







Capacity of the sauna






Measurements and weight













Heater weight/ Amount of Ceramic Stones/ Amount of Olivine Stones

190kg/ 60kg/ 90kg

270kg/ 90kg/ 160kg

305kg/ 130kg/ 220kg

715kg/ 260kg/ 290kg 

1775kg/ 600kg/ 650kg

Connective flue’s outer diameter






Connective flue from the lower corner of the floor*







enamel-lined, black

enamel-lined, black

enamel-lined, black

painted, black

painted, black

Safety distances**

To the sides






In front












To the rear






* This is so the sauna bench remains high enough from the surface of the sauna heater. 

** Safety distances are to combustible materials.

About Narvi Oy

Product Disclaimer

All Aito heat storing sauna heaters are CE tested and bear the Finnish Key Flag Symbol. This is awarded to heat storing sauna heaters that are made and designed in Finland, where over 95% or more of the production must be within Finland itself. There are many brands that claim to be made in Finland but are actually made in the Far East or Russia and merely assembled or labeled in Finland. Watch out for these symbols as a mark of an authentic, Finnish-made, safe, quality product:

Finnish Key Flag and CE Marked

As part of Finnmark Sauna's Endurance Ethos, we only deal in products that are market leaders in quality. We commit ourselves to search exhaustively for the highest quality authentic Finnish sauna products.

Please note, we recommend that sauna heaters should be installed by a suitably qualified electrician/builder/plumber/fitter. Finnmark Limited accepts no liability for loss or injury caused by the incorrect installation of your sauna heater. Please Contact Us if you require information on our recommended fitters.

Purchasing & Delivery

Before You Buy

To avoid disappointment on day of delivery, be sure to measure the area you plan to place your new sauna equipment and compare this with measurements under the product specification tab, before placing your order. Please ensure you measure any doorways (height and width) through which any large sauna equipment must pass to get to its final position. Identify any delivery obstacles and check that the sauna equipment can clear any stairs, low ceilings, sharp corners or elevators. Please note, we use independent couriers to deliver all our products and thus we cannot confirm whether the courier is willing and able to help with delivery beyond the threshold of the property. Should you require any specialist delivery support, please contact us to discuss ahead of your purchase.


- Recorded Next Day Delivery* is available on all marked products for orders to the UK Mainland. The product will be marked as such within the product description ("Order before 2pm to guarantee next day delivery on this item") where this service is offered. The customer must order before 2pm to guarantee receipt of the product Next Day*. * Next Day Delivery guarantees next working day only, for orders within UK Mainland.

- All other products** are subject to 3-10 working days shipping time with tracked and recorded courier. Please note, some of our items are shipped direct from manufacturer. ** Excludes sauna cabins & installations.

- Sauna Cabin delivery times can vary considerably, especially those that are made to order. Please contact us for manufacturing and delivery time estimates for sauna cabins. Where installation for cabins and bespoke installations is requested, this will be completed in the next available time window which may be sometime after the delivery of goods. Please contact us to confirm delivery and installation requirements and timings.

- Expedited Delivery or installation services may be available upon request, but extra charges will apply.

Warranty Information

Manufacturers Warranty

A two year manufacturers warranty applies on all products commencing from the point of sale/purchase from Finnmark Ltd.

#1: What does this warranty cover?

The warranty covers it covers any defects in material and workmanship under normal use. A warranty claim cannot be made on domestic equipment being installed in a commercial environment.

#2: What will we do to correct problems?

In the rare case that a warranty claim is required, Finnmark Ltd provide replacements for any confirmed broken parts of a product. Where this is not possible, Finnmark may offer a replacement but the customer may be required to return the product to Finnmark Ltd or to the manufacturer, at the customers expense. The customer should follow the claims procedure laid out below.

#3: How long does the coverage last?

The manufacturers warranty covers all items purchased directly from Finnmark Ltd for 2 years commencing the point of sale/purchase by the customer.

#4: What does this warranty not cover?

The following are not covered by the manufacturers warranty:
- Theft or loss of the product.
- Usage of domestic equipment within a commercial environment.
- Damage of a product resulting from negligence.
- Damage of a product resulting from unauthorized modification of the product.
- Damage caused by natural disaster.
- Consequential and indirect damage caused.

#5: What do you have to do?

To make a warranty claim, the customer is required to:
- Provide all information required by Finnmark to assess the issue.
- Finnmark Ltd may request detailed photographs of the product. For example a heater may require photos of the elements, power supply and drivers to assess what may be required to fix the product.
- Finnmark Ltd will make a judgement based on this information as to what replacement parts may be needed or if the product needs to be returned and replaced.
- Where a replacement is granted, the customer must first return the initial product to Finnmark Ltd or may be required to be sent to the product manufacturer, this will be confirmed by Finnmark Ltd during the claims procedure. The return shall be at the expense of the customer and should be sent via a recorded courier service. Finnmark Ltd holds no liability for items lost or damaged in transit.

#6: Applicable Laws

All warranty claims are handled in accordance with the laws of the United Kingdom where Finnmark Ltd is based and registered.

Payment Information

We are currently able to accept the following payment methods:
- Credit & Debit Card (including Mastercard, Visa & American Express)
- Paypal
- Amazon Pay
- Bank Transfer