Household air quality indicator RaDEC


The device measures the following quantities:

  • Radon concentration Rn, radon volume activity (RVA)
  • Equivalent dose rate from photon radiation (X-ray and Gamma radiation) (not in RaDEC light version)
  • Carbon monoxide concentration CO
  • Carbon dioxide concentration CO2
  • Relative concentration of volatile organic compounds VOC
  • Temperature T
  • Relative humidity RH

RaDEC is primarily intended for the indication of substances harmful to the human body in the indoor air of buildings and for measuring additional parameters of this environment. It can warn the user in case of increased limits of harmful substances and the user can immediately take appropriate actions, such as good ventilation.

RaDEC is equipped with a colour display with touch control and a touch power button (TESLA logo) on the top of the case.

In addition to the instantaneous value of the quantity shown on the display, the device also creates periodic records of all measured quantities. These records can be displayed for individual measured quantities in the form of a graph on the display with a length of 100 items.

RaDEC can be powered from the mains or from the built-in accumulator.

Thanks to the built-in accumulator, the indicator is portable and can be used for measurement even in areas without power supply for at least 7 days.

It is possible to set two alarm limits “notification” and “warning” for the measured quantities, the exceeding of which is indicated optically on the display and acoustically by an internal siren.

The device also displays the current date and time.

RaDEC can be placed anywhere in the room. It is recommended to place it as far as possible from windows or ventilation equipment. The back of the indicator should stay uncovered.

Technical parameters
Sensitivity when measuring Rn concentration0,055 imp/hr/Bq/m3, measured from RaA+RaC
Rn statistical error at 300 Bq/m3± 24% at 1 hr measurement
± 5% at 24 hr measurement
Rn measuring rangeapprox 30 – 60000 Bq/m3
Gamma detection sensitivity0,75 imp/sec/1uSv/hr (not in RaDEC light version)
Gamma measuring range0,1 – 10000 uSv/hr (not in RaDEC light version)
Gamma measurement and display interval3 sec, value smoothed by weighted averages (not in RaDEC light version)
CO measuring range0 – 800 ppm
CO measurement and display interval3 sec
CO measurement accuracybetter than ± 20% / 5 years
CO2 measuring range0 – 40000 ppm
CO2 measurement and display interval1 min
CO2 measurement accuracy± 20%
VOC measuring range1 – 100%
VOC measurement and display interval3 sec
T measuring range-40 – 125 °C
RH measuring range0 – 100%
T, RH measurement and display interval1 min
RH measurement accuracy± 5%
Max. number of records2570
Records interval1 hour
Records valueradon: current value of the moving average
other quantities: hourly average
Power supplybuilt-in accumulator or charger via USB-C port
Accumulator life timemin. 7 days
DimensionsØ130 x 110 mm
Guaranteed operation conditionstemperature: +10°C to +50°C
relative humidity: 0% to 80%

Display examples of quantities and possible functions:

Basic display

At the bottom of the display are the symbols of all measured quantities together with the instantaneous value and units. By pressing any quantity symbol, the name of the quantity and the measured value will appear in the main field of the display (radon measurement is selected in the figure). The currently selected symbol at the bottom is displayed without a measured value.

Fig. 1 – basic display

The colours of the individual symbols of the quantities express the current state of the value of the quantities within the alarm limits. If the value of the measured quantity is “OK”, the symbol is coloured green. Exceeded limit of the type “notification” is visually indicated in yellow, limit of the type “warning” in red. No alarm limits are indicated for the “Temperature” and “Humidity” quantity symbols.

Charts display

The graph created from the records of the quantity that is selected for display in the main field on the basic display is displayed. To change the graph to another quantity, it is necessary to go back to the main display using the back arrow in the upper field of the display. The graph display shows the course of the quantity indicated in the upper field of the display.

Fig. 2 – charts display

In the upper field of the record, the text “Record x of y” indicates the total number of records (y) and the record on which the white cursor (x) is located. In the middle below the graph is the value of the measured quantity record in the graph, where the white cursor is located.

In the graph it is possible to move through the individual records (points) using the arrows < and >. Using the << and >> buttons it is possible to jump by 100 graph records (pages) forwards and backwards. If there are fewer entries, pressing these buttons does not work.

The graph also shows the currently set alarm limits “notification” and “warning” for the given quantity by a yellow and red line.

Configuration display

The top line is the same for all configuration displays. It contains a back arrow, which is pressed to go to the basic display and at the same time saves the set configuration values and a line of 5 symbols that define the individual configuration displays of “alarm limits”, “time”, “display”, “sound” and “factory settings”. The selected icon is always lightened.

Alarm limits configuration display

It is possible to set two alarm limits “notification” and “warning” for the measured quantities, exceeding / passing below of which is always indicated optically on the display (in case of display off this display lights up for 5 seconds) and acoustically by one beep of the internal siren. If any alarm persists for a long time, the acoustic and optical alarm indication is repeated with an interval of 30 minutes.

Fig. 3 – alarm limits configuration display

Alarm limits have an established hysteresis of +/- 10% of the set value for exceeding the limit. Exceeded “notification” limit is visually indicated in yellow, “warning” limit in red. Acoustic alarms can be turned off in the “Sound configuration display” setting.

The alarm limits for the measured CO quantity cannot be reset by the user due to the high danger of CO and the importance of the alarm. For the same reason, an acoustic alarm cannot be switched off for the measured CO value. If the CO limit is exceeded, the internal siren starts beeping 5 times with a repetition interval of 3 seconds and the display lights up permanently.

The default limit values established on the basis of international hygiene and medical recommendations are as follows:

Factory setting of limits
notification warning

When setting limits, the bottom line of symbols allows you to select the quantity whose limits will be set. The factory values of the alarm limits correspond to the above table, the values can be changed by the user by pressing the + and – buttons or by pressing the alarm value (the number keypad pops up). The factory values of the alarm limits can be reset on the “Factory settings configuration display” at any time.


  • This device has 24 months warranty period from the date of purchase.
  • In the event of a warranty claim, contact the service department.
  • The warranty covers material or manufacturing defects, not damage caused during transport and handling and improper usage.
  • In case of incorrect and unprofessional use or if the seal is broken, the warranty expires.
  • The warranty performance extends the warranty period by the repair time.
  • At the end of its working life, the product must be treated as electronic waste.


RaDec Technical Specifications & Operation Manual EN

RaDec Technical Specification & Operation Manual DE