Bath stove, equipped with a heat exchanger, performs several functions simultaneously. In addition to its direct purpose, the stove with a heat exchanger successfully heats water for the shower. And if the design is made in the form of a remote tank, located in an adjacent room, the device simultaneously heats the room. There are 3 variations of the heat exchanger device:
- Internal. In this case, the sauna stove is equipped with a coil, located at the bottom or side.
- External. Made in the form of a rectangular tank, the liquid heats directly through the wall of the sauna stove.
- Outdoor. Represents a hermetically sealed vessel encircling the chimney pipe.
The principle of operation of all heat exchangers designed for sauna stoves is identical due to the contact with the red-hot surface of the chimney or furnace, they heat water for large volumes of containers, based on the principle of convection. Their operation allows the water tank to be installed in the adjoining steam room.
Common Myths regarding Furnace Heat Exchangers

Regardless of the design, all heat exchangers are filled with liquid. Depending on the purpose of the device, it can be ordinary water or antifreeze. Liquid flows from a communicating tank (storage tank or heating system). It is connected by two connectors at the top and bottom. The whole scheme of the device of the heat exchanger is not complicated: it is based on the natural circulation of the heated liquid or by connecting an electric pump.
Professional stove builders recommend opting for an open water heating system, without the use of pressure. Also consider the effect of the length of pipes on the efficiency of the entire system. Optimal is considered a length not exceeding three meters. This is quite enough to take the container with heated water into the next room.
The thickness of the pipe also matters. To work without an electric pump, the diameter must be greater than one inch. Otherwise, the sauna stove, equipped with a heat exchanger, will not cope with the distillation of liquid on its own.
Installation work
The last step is left. to install the heat exchanger in a brick-built stove. Standard stove for the bath consists of several elements: the stove-fireplace directly, the chimney, heat exchanger, remote tank and connecting elements (valves, pipes).
Experts advise as a place to install the heat exchanger to choose a place near the furnace, inside the brick jacket.
Keep in mind, that the furnace is laid with bricks to the level of the firebox, only after that performs installation of a heating unit, then the chimney. Although some experts recommend putting a heat exchanger in the chimney, as they consider this scheme optimal for the combustion of fuel.
Choosing a stove for the bath with a heat exchanger for water and heating
Washing in a bath need hot water. And there are several solutions to this problem. It is completely absent if the settlement has a network of hot water supply. But still more often the homeowner himself should take care of heating water for household needs. A radical decision to have a boiler that can cover the needs of the house and bath. But it is easier and more profitable to use bath stoves on solid fuel if you use them seldom.
By the location of the tank for warm water
Depending on where the tank with water is located, there are the following types of heaters:
Blower and heat exchanger cleaning
- A tank directly in the steam room. allows water to boil faster, t. к. The water pipe is absent or very short. it also cuts down on heat loss. The disadvantage is quite obvious: the usable area of the steam room is reduced.
- The tank is in the adjoining room where the shower room is installed. Often this option is recommended. It is more convenient to wash in a separate shower room, and there is more space in the steam room. But the length of the water line grows.
- The problem of low pressure can be solved by installing a tank with a coolant in the attic. This method is also not without disadvantage. It is necessary to bring cold water upstairs, and the length of hot water line is longer. The tank must be carefully insulated to reduce heat loss as much as possible.
What is the best heat exchanger for a sauna stove?
In addition to heating the steam room to the desired temperature, for a comfortable visit to the sauna or bath need a large amount of hot water. Solve the problem in different ways: the installation of a boiler or flow-through water heater.
Judging by consumer reviews, the most economical and heat efficient solution is considered a heat exchanger for the sauna stove. The device, depending on the design, provides the needs for DHW and allows you to fully heat the adjacent rooms: the washing room and the pre-bathroom.
Mounting the tank from a part of the pipe
Next, you can proceed to installing the hot water tank. To the end part of the tank from below, weld a steel circle at least 8 mm thick. In a circle cut a hole for the chimney with a diameter of 12-15 cm with an offset to the back of the tank. Next, secure the underside of the flue pipe to the bottom of the furnace tank. This is necessary to avoid the possibility of water leakage into the furnace.
Cover the top of the tank with a semi-circle made of steel with a drilled hole for the pipe. The chimney itself is welded tightly to this opening. This leaves the top of the tank open to pour water. To close the neck, make a lid with a handle.
On the chimney, at a distance of 35 cm from the tank, weld a steel plate measuring 30×30 cm. At the site will be mounted brick chimney with a special damper, since this design of the chimney is expected to have an exit through the ceiling and roof. At the bottom of the tank, opposite the hole for filling water, weld a valve.
How to calculate the area of the heat exchanger
It is not uncommon when home craftsmen take on the manufacture of such a device with their own hands. To do this, they should learn to calculate the necessary parameters relating to the provision of sufficient heat and volume of hot water for bathing.
When calculating the dimensions of the device is allowed rounding. So when installing a heating system with a capacity of 5 kW you need a device, the usable area of which is defined as 1m². This example is quite approximate, because the device with similar parameters will also be provided with heat with the participation of the stove with a capacity of 9 kW. It is still better to calculate the size of the area, leaving some reserve. During the cooling of the unit power is significantly reduced, and the reserve allows you to maintain the temperature in the room until the next firing of the furnace.
When choosing a heat exchanger, the last thing worth paying attention to is the shape of the device. There are no special requirements for this parameter, so you can safely rely on your imagination. Often the heat exchangers, as well as the pipe system, are made of stainless steel. It is quite durable and effective in operation. The only disadvantage is the occurrence of some difficulties when performing welding work.
Heat Exchanger with Your Own Hands for a Sauna Stove. DIY
Main advantages
The undoubted advantages of using a heat exchanger in the design of the furnace are:
- Simultaneous performance of several functions: heating water, air in several rooms, as well as steam formation;
- Options to install the tank at a considerable distance from the oven (even in another room);
- Durability. When using modern materials and observing the technology of installation the service life is up to 20 years.
- Aesthetically pleasing appearance
- Accessibility of maintenance;
- Easy installation;
- High efficiency;
- The possibility of installation in a Russian traditional bath, as well as in a modern Finnish sauna;
- Space saving due to compact size;
- High power and, as a consequence, quick heating to the desired temperature;
- No (or negligible) deformation when heated
The advantage of the sauna stove with a heat exchanger
The most important advantages of furnaces with a heat exchanger can be considered the following parameters:
- Bath system with a heat exchanger performs two functions at once: it heats water as well as the steam room and pre-bath room.
- The tank of such a system can be located in a room adjacent to the steam room.
- Stoves of this kind, the cost of which is not so great, are made of quality material with a long service life.
- The furnace of a modern furnace is equipped with fireproof glass, thanks to which you can enjoy the burning of the fire, while controlling the process itself.
- The appearance is quite attractive, and the system itself is unpretentious in care.
- I would like to note that the stoves of such design are simple in terms of installation, which is possible with your own hands.
- The small size of such a sauna stove allows you to save space in the steam room.
- Also the power of such system copes well with the rapid heating of the room assigned to the steam room to the desired temperature.