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Sub Floor Ventilation – Solar Air Modulesolar-whiz-for-sub-floor-ventilation-diagram


Efficient ventilation of sub floor areas is crucial to the health and durability of any building with a sub/underfloor area. Continual high moisture levels may cause irreparable damage to the structure of the house – as well as elevated humidity and reduced indoor air quality, severely impacting on the health of its occupants.


Condensation is normally a strong gauge of high humidity levels in any home – and will often lead to mould development. This is both unpleasant and poses an immense health risk – as it is a major trigger for asthma attacks.


High moisture levels inside any home increases the risk of developing asthma and allergies as well as other respiratory problems such as excessive coughing, wheezing, higher susceptibility to developing colds, sore throats and nasal or sinus infections.


For many people (especially younger and older), high humidity may also result in skin and eye irritation, joint pain and headaches. Under floor ventilation is often the best place to start addressing these issues; but it may not always be the complete answer to your damp problems.


If you don’t have a sub floor area – alternative methods for addressing these issues may be required to improve the indoor air quality. Please see our Solar Whiz and SAM products to see how they can help you with these problems.


Damage caused by poor ventilation in sub-floor areas

High humidity levels under the house will result in a damp sub/underfloor, causing mould, fungi, rotting floor boards and stumps, odours and mustiness. Moisture can make its way into the house causing serious damage to your internal walls and painted surfaces. In the worst case scenario major damage such as crumbling of the brick walls of your house may occur. Major damage is also likely in the sub/underfloor areas due to the moist conditions creating ideal breeding grounds for termites, white ants and wood borers.


Underfloor Ventilation Reduces Asthma Symptoms

Solar ventilation inside and under the houseAsthma sufferers should be aware that asthma attacks are generally triggered by poor air quality, which might be caused by issues in the sub floor area. The most common approach to sub floor ventilation is constant or timer operated mains powered fans.


These fans are designed to remove moisture from the sub-floor area – with the aim of allowing replacement air to enter the area under the house via vents located around the building. The problem with constant or timer operated fans is that they also operate when there is high humidity e.g. when it is raining – which means that they actually bring damp air into the sub floor area. Due to the normally lower temperature under the house this causes condensation – and a deterioration of conditions – not an improvement.


The SAM unit can be used to resolve sub floor damp issues. The SAM provides heated air which, when blown into a damp sub floor area, will evaporate the dampness and ventilate the sub floor, therefore eliminating the problem. The SAM unit can be wall mounted so the ducting from the collector to the fan is short and minimises heat loss. The 150mm diameter fan used for the SAM is very popular in sub floor ventilation jobs because it only requires a 150mm wall penetration hole. If an extraction fan is required you just need to add an additional 8 Watt fan and 18 Watt PV panel to the SAM system.


Using a SAM to ventilate a Sub Floor area will help address the following issues:


Mould in Subfloors can be prevented using Solar Air Heating Modules

  • Mould
  • Mildew
  • Condensation
  • Rotting Floor Boards and/or Stumps
  • Damage to Internal Walls & Paintwork
  • Crumbling Brickwork
  • Breeding Ground for Termites, White Ants & Borers


Solar powered fans offer a couple of obvious advantages over the traditional mains powered and timer operated systems:

  • The systems only operate during sunny conditions – ensuring that the replacement air generally is quite dry and therefore contributes to keeping the sub floor dry
  • Solar powered fans cost nothing to operate

Global Eco & Environmental Solutions offers a variety of Solar Powered sub floor and underfloor ventilation options:


  • Solar Whiz – High volume – Sub floor/gable fan for moisture extraction from sub floor requiring about 500 mm diameter for installation
  • Where less space is available in the sub floor area GES offers a series of Inline fans




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