Heated floors

These days, there still are people who believe the myths about the harm caused by heated floors, such as footaches, excessive dust and that you cannot lay heated floors down in bedrooms or beneath wooden floors. The European (ISO 7730) and Lithuanian (HN 69:2003) hygiene standards state these requirements for comfortable temperatures:

  • Room temperature 20-24°C, floor temperature 19-26°C, vertical temperature differences <3°C
  • Room moisture (40-60%)
  • Average air movement speed (0,1-0,25 m/s)

The optimal room temperature is 22°C. When comparing with a convectional system (radiators, convectors or air heating), floor heating provides the same perceptible temperature while keeping the air temperature 2°C lower (20°C), which gives a sizeableoperational efficiency of 12%. Floor heating gives off 50% of the heat by radiance(depends of the heating space and the distance to it – the whole heating surface and the person are in direct contact) and 50% by convection (the temperature difference between the heatable surface and air).

Experiments have determined that the optimal floor temperature is 24°C – the person will feel discomfort when the floor is too cold (<19°C) or too hot (>26°C). The maximum floor temperature (29°C) is allowed only under certain circumstances when you need to deal with significant heating losses (<100W/m²), and in a small timeframe (when the temperatures outside are critical). When correctly installing and using the floor heating system, the floor temperature is usually 22-26°C, so the difference between the surface temperature and the air temperature is 2-6 degrees at most – too small for dust to settle. Obviously, the temperature difference and air convection is much bigger when using convectional heating. Laboratory tests conducted in Germany have determined that the conditions for the spread of dust mites and alergens when using floor heating are much worse than when heating with radiators. A study has been conducted in Sweden that has indicated how floor heating should be set up under wooden floors. Scandinavian preschool microclimate study findings indicate, that floor heating should be mandatory in kindergarten play rooms.

The findings of all studies and experiments are contrary to the common myths:

  • It has been proven, that the vertical temperature curve of floor heating is the closest you can get to the ideal heating curve
  • Only by using floor heating can someone ensure comfortable floor temperatures
  • The air movement when using floor heating is minimal because of the small differences of temperatures
  • Due to the lower amount of air circulation happening, the conditions for the spread of dust mites and alergens are much worse
  • When heating the floor, you always have warm and dry floors – worse conditions for dust mites.
  • You can use wooden floors above floor heating (the “worst” are carpeted floors)

Conclusion: In buildings with good thermal insulation and floor heating, the people feel that air quality is better at lower air temperatures. It has been proved by experiments, that warm floors, colder and dryer air is better from the point of health and hygiene than standard convectional heating by radiators. When assesing the design advantages – there is no visible heating equipment and no restrictions to furniture layout, and lower running costs, the floor heating system is the best choice.

One of the stages of installing a heated floor