1. Correct placement of the measuring device
- at least 25 cm from the nearest wall
- at least 50 cm above the floor
- at least 150 cm from the nearest window, door, radiator or ventilation slits
- no direct sunlight
- protect from dripping water or moisture
- rooms with ground contact (soil) tend to have a higher radon load
- dormitories, hobby rooms or children's rooms (rooms with a long stay) should be at the top of your list of measurements
- place your measuring device where you "breathe" I.e. at your desk at head level, in the bedroom on the bedside table, in the hobby or sports room at eye level.
2. Pay attention to weather and environmental influences
Radon values are subject to strong fluctuations. Especially the weather and also the season have a strong influence on the measured radon values. For this reason, we recommend that passive long-term measurements are always carried out in parallel to the short-term measurements.
In summer the measured values tend to be lowest. In spring and autumn you (usually) get a good average value of the average exposure over the annual average. In winter the measured values tend to be higher due to:
- worse ventilation behaviour
- frozen floor / walls, which become more permeable to the radon gas
- Chimney effects in the house (through strong heating)
For this reason, it is recommended that at least part of the measurements (long-term measurements) be taken in spring or autumn.
3. Measurement duration for radon measurements
The longer the measurement period, the more accurate the measurement result. Air pressure, humidity, temperature, wind, rain, sun can also have an influence on the measured radon values. For this reason, a measurement duration of at least 7 days per room is recommended (for short-term measurements). Short-term measurements are good to get a first impression of the current situation, but in addition to short-term measurements, long-term measurements over several months should also be carried out.
4. Extreme value measurement
If you want to carry out an extreme value measurement at your home, you should not enter the room or ventilate it for days before the actual measurement. During the measurement, the room should also not be entered or ventilated. In this way you can determine your maximum radon exposure.
5. Realistic radon value
In order to get the best & realistic average value of your radon exposure, you should continue to use the desired room as usual. This means that you should not change your habits (door open/closed, ventilation behaviour, usage behaviour) during the measurement. It is best to start the measurement and simply ignore the measuring device for the next few days. This will give you a radon value that reflects the real exposure (but please also consider point 2, that e.g. in winter your ventilation behaviour can change).
6. Typical measurement errors when measuring radon
- Measuring time too short
- Changing the position of the measuring device during the measurement
- Wrong measuring point
- Other use of the room than usual (in the case of extreme value measurement this is done intentionally)
Normally, the radon levels are highest in the basement rooms and decrease with each additional floor. However, due to structural conditions (gaps in the walls, chimneys, electrical ducts, water supply shafts, ventilation shafts, heat insulation cladding, etc.) chimney effects can occur, which literally suck the radon gas into the upper floors. Only a measurement in the respective rooms can give you certainty.
7. Measurement results of the neighbour
Measurement results from your neighbor or measurements that have been taken in your area cannot give a reliable statement about your own radon exposure in your house. Radon can change from little to extremely much within a few meters due to different soil layers (clay, gravel, groundwater, etc.). Also the characteristics of each building (tightness of the floor slab, walls, pipe penetrations) are individual. Likewise, the ventilation behaviour and the use of space are different. Our recommendation is therefore clear, that only your own measurements can provide real information about your personal radon situation.