Positive ventilation brings fresh air into a home, and dilutes the radon. The flow of air and radon from the ground may also be reduced.

A positive ventilation system can be effective in homes with radon levels up to and around 500 Bq m-3.


Positive ventilation systems work best in well insulated, draught-free homes - especially bungalows.

A typical system has a fan in the roof-space connected to a vent in the ceiling. There are units for properties, such as flats, without a roof space. A filter ensures that the air is clean:

  • Some units have an optional heater
  • The fans are quiet


Installation is quick and simple; the units are normally supplied with a fitting kit. A vent is fitted centrally in the ceiling, normally in a hallway or stairwell. The vent is connected by a flexible duct to the main unit which is supported by the ceiling joists or the rafters in the roof space.

The typical cost is £550, but might be up to £1000; installation normally takes a day or less. The fans fitted in many units use similar amounts of electricity to an energy efficient light bulb.

The systems improve air quality and may also reduce condensation.

For more detailed information, please refer to the downloadable guidance below.





How to reduce radon levels overview


Disclaimer. It should be noted that the measures described on this sheet are not guaranteed to reduce the radon level in your home, however similar measures have been proven successful in many UK homes.