As depicted in the above image, 12 volt sub floor ventilation systems and 240 volt sub floor ventilation systems provide very different damp solutions for sub floor areas.
Each sub floor ventilation system has its own characteristics, especially when it comes to the attachments needed.
12 Volt Sub floor Ventilation Systems
The 12 volt system doesn't require any attachments, as the 12 volt sub floor ventilation system replaces terracotta vents as a ‘retrofit’.
Damp solutions are achieved by humid air being drawn toward the strategically placed 12 volt sub floor ventilation system and allowing the air to flow freely out from the problem area.
240 Volt Sub floor Ventilation Systems
240 volt sub floor ventilation systems (as shown above) require flexible ducting, dampers, branch fittings etc.
These materials are installed in the sub floor area as well as the sub floor ventilation system itself. Sub floor ventilation has to flow around these objects.
These ducts often penetrate through sub walls which means that the penetration has to be large enough to accommodate the 150mm ductwork, which may weaken the sub wall structure.
Sub floor ventilation companies who install 240 volt systems use one fan and sometimes multiple units to draw humid air into the piping configuration and then to the outside, providing their version of a damp solution.
The flow rate of these units are 8,000 litres or more per minute, at a noise rating of around 48-60dba at 240 volts.
12 volt sub floor ventilation companies use multiple units that replace certain terracotta vents to provide damp solutions for the specific damp area.
The flow rate of these units are 5,500 litres per minute at a noise rating of 27dba at 12 volts.
12 volt sub floor ventilation system provider, Envirofan argue that their experience over the years and in the testing process of 12 volt sub floor ventilation systems in the 1970’s has demonstrated three things.
Firstly the effectiveness in providing damp solutions is not extracting massive amounts of air in a short period of time but moving lower volumes of damp air over a longer period.
Secondly in providing an installation which doesn’t impact on the building structure itself and thereby retrofitting existing terracotta vents changes their characteristics from ‘passive’ to ‘active’ sub floor ventilation systems.
Thirdly in getting an effective damp solution, utilising 12 volt sub floor ventilation systems users won't require accessories or increased power consumption to drive them as may be necessary with larger systems.