Family house Rumburk

Introduction

Radon is a naturally occurring radioactive gas which, at elevated concentrations, can pose a serious health risk. In the Czech Republic, it is one of the primary sources of radiation exposure in residential buildings. This study presents a case analysis of a family home in Rumburk, where in 2011 a controlled ventilation system featuring the unique VENTBOX mode was installed to eliminate radon. The system remains fully operational to this day.

Objective

To demonstrate the effectiveness of pressurised ventilation with heat recovery, including the specialised VENTBOX mode, in reducing high indoor radon activity concentrations (OAR) in living spaces.

Methodology

Initial condition

Before installation, the house — built in the 1960s on weathered, permeable granite — had minimal or no protection against radon. The average indoor radon concentration reached approximately 4,500 Bq/m³, with short-term peaks in some rooms as high as 6,000 to 10,000 Bq/m³.

System installation

Undercutting the house and subsoil ventilation were not feasible, so pressurised ventilation technology was selected. Helix 400 units — the predecessors of the VENTBOX 400 series — were installed in selected areas, featuring heat recovery and a specialised radon elimination mode. Following system activation, repeated measurements were carried out by a certified expert, with independent verification of the results conducted by the State Office for Radiation Protection.

Results

Radon reduction: Following installation, the indoor radon concentration (OAR) dropped below the recommended safety limits.
Energy efficiency: Thanks to heat recovery and controlled pressurisation, indoor temperatures remained stable, contributing to energy savings on heating.

Conclusion

The Rumburk case study demonstrates that the VENTBOX controlled ventilation system, with its unique radon elimination mode, is highly effective in reducing radon concentrations in residential spaces. Remarkably, the system has remained fully functional even after 14 years of continuous operation. This approach not only mitigates health risks associated with radon exposure but also supports energy efficiency, making it a suitable solution for homes and other buildings. An additional benefit of the system is its ability to regulate CO₂ levels, humidity, and volatile organic compounds, further enhancing indoor air quality.