FAQ Questions and answers regarding electric heaters
- Can any stone materials serve as heater stones?
- What factors should be taken into consideration when choosing the power of a heater for a sauna room?
- How often should the heater stones be changed in a family sauna?
- What do safe distances from heaters mean?
- Can an electric heater give you an electric shock?
- Can the heaters electrical circuit be fitted with a residual current device (RCD) to eliminate the danger of electric shock?
- What is the correct temperature of a sauna?
- Can I use my electric heater if one/some of its resistors are broken?
- Can anyone connect a heater to the mains, and who has authorisation to change a broken resistor?
- Can the materials in sauna heaters cause unpleasant odours?
Heater stones should be of a material that is as heavy as possible, dark in colour, and large in size for them to be able to store as much heat energy as possible. Heater dealers sell stones that are purposely intended for use as heater stones and which come from well-known suppliers, and whose composition and suitability are guaranteed. Stone material that is well-known and suitable for use in heaters includes: peridotite, olivine and olivine-dolerite. Heater stones must be arranged loosely to ensure there is good air circulation.
The walls and ceiling of the sauna room should have good heat insulation, especially if the room is to be heated by means of an electric heater. The wall materials of the sauna, such as concrete, logs, glass, tiles, brick, glass bricks, etc., require a relatively powerful heater and quite a long time to heat up. The larger the sauna is in terms of capacity, the greater the heater power should be to heat up the room sufficiently well to take a sauna bath. When approaching a heater dealer you should know beforehand what the wall materials are in your sauna and the capacity/inside area of the sauna. Air-conditioning in the sauna room must be arranged in such a way that it does not cause the heat produced by the heater to be wasted. Much research has been done on the proper air-conditioning system for saunas, and for many years this has been applied at the planning and implementation stages of sauna ventilation in any new construction. The manufacturers product brochure, available from the heater dealer, gives further detailed instructions relating to choice of heater power.
How often they are changed by and large depends on how much the heater is used. If it is an average of twice a week, the stones should be changed once a year. It is a good idea to rearrange the stones occasionally, as they tend to crumble with use, making the area more compact and therefore obstructing the free circulation of air. Good air circulation will ensure that the heater works properly and the resistors too will last a long time owing to lower temperatures at their surface.
Safe distances are minimum distances from combustible materials that must be observed to prevent the danger of fire. The manufacturer gives the relevant safety distances based on studies and safety regulations, and they must not be reduced as that might create a fire hazard!
Electric heaters are safe to use when installed correctly. The Safety Technology Authority (Turvatekniikan keskus) monitors the electrical safety standards of heaters and gives manufacturers and heaters a certificate of safety. In Finland approved heaters are marked FI. Heaters may carry certificate labels from other countries. Heaters are connected to the mains supply in such a way that their touching metallic parts are earthed. Live components are prevented from coming into contact with one another as part of the design.
Do not connect the power feed for the heater through the residual current device. It is not necessary as the heater is earthed and therefore sufficiently protected. A residual current device is for securing the safety of small electric appliances eg. coffee maker.
The temperature of the sauna must be one in which the user sweats while seated on the sauna bench and feels comfortable. There is no right or wrong sauna temperature as everyone has a different sensation of what suits him/her best, taking into account age and state of health. If the sauna temperature is high (80–100oC), the body will not sweat easily, even if you try to make the air humid by throwing water on the stones. With a low sauna temperature (50–60oC) it does not feel dry as you can use plenty of water to humidify the air. Bathers can bear to stay in the sauna and it feels comfortable and pleasant! With traditional basic heaters it takes a fairly long time to get the heater stones sufficiently hot and the sauna temperature can easily get too high. To keep the sauna at a suitably low enough temperature you must choose a heater such as the Harvia Forte (Ever-ready) electrical heater, which can regulate the sauna temperature as required by means of its air circulation valve.
A broken resistor should be changed immediately, as the ones that are still intact have to burn longer under the control of the thermostat, and a while later one of the remaining unbroken resistors may also break.
All electrical appliances that are fitted with protective housing that is attached by screws to prevent dangerous live components from coming into contact with one another, must be installed and serviced, in compliance with the regulations in place, by a professional, authorised electrical engineer or any such other knowledgeable person.
The first heating of the sauna heater removes residual protective and processing substances from different manufacturing phases. These substances may cause unpleasant odour and even smoke in some cases, and it is therefore important to have the sauna well ventilated during the initial heating. Because of the odour it is not recommended to go to the sauna during the initial heating.
Note also that in case any such repair work has been carried out anywhere in the flat that has required the use of paint, varnish, glue or other substances that contain evaporable components (solvent vapours), even small amounts of such materials will cause a strong petrol-like odour as the vapour passes through between the hot rocks and resistors of the sauna heater. The odour wears off when the solvents in the flat have completely dried out.
Heating the sauna heater might furthermore emphasise other odours mixed in the air that are not, however, caused by the sauna or the heater. Onion and other strong seasoning used in cooking are some of these odours. Also, odours from the garage or a near-by oil filler neck may mix into the incoming air of the sauna and be detected when going to the sauna.