ProAir FEX Terminal

ProAir Fex Terminal - Patent Pending

The FEX Terminal is a low cost efficient solution that facilitates the ingress and egress of air to and from a MVHR unit.  It ensures that no cross contamination of Fresh and EXhaust airflows occur as they enter/leave the building. The FEX Terminal is proprietary to ProAir Systems with Patent Pending status. The terminal has been independently tested by the Centre for Sustainable Energy of Galway Mayo Institute of Technology (GMIT). It is available for sale directly from ProAir Systems.

Challenges with current systems today:

When installing HRV systems up to now the fresh and exhaust air streams had to be separated so (i) that no cross-contamination ocurred and (ii) that the exhausted air is not sucked in at the fresh air inlet. This generally meant having two penetrations in the building envelope and taking two ducts (usually 150mm diameter) along the inside of the building to the HRV unit. As these duct lines will be as cold as outside, they will need to be highly insulated and indeed ideally, as highly insulated as the walls of the house. This is why it is recommended that these lines are kept as short as possible, but yet avoid cross-contamination. This can prove difficult and expensive to achieve.

FEX Terminal Benefits

The ProAir FEX terminal is a cost effective and simple solution to this problem. The uniqueProAir Fex Terminal - side view(patent pending) design of the FEX terminal allows the two air streams to penetrate the building in one opening approximately 150mm wide and 300mm high. In the top part of the unit fresh air is taken at the sides of the unit. In the lower half of the unit air is exhausted at 45 degrees away from the building at the bottom of the terminal. As the exhaust air is moving away from the building at speed, a situation never arises where this air curls back and is sucked into the inlet.

    • Simple, easy to install solution
    • Independently tested to confirm no cross contamination of air flows
    • Improves energy efficiency of HRV System and building
    • Reduced ducting and installation costs

  • Size: 150mm wide x 300mm high
  • Patent Pending
  • Tested by The Centre for Sustainable Energy of GMIT (Galway Mayo Institute of Technology)
PA Fex Terminal - side view 



  • Component Plates
ProAir Fex Terminal - side view 
  • Fresh air is taken into the house via the top 150mm round duct and exhaust air is removed via the lower 150mm duct
  • The terminal (both parts) is mounted on the wall outside.
  • The terminal on a side wall of a house in Co. Galway

Airflow Performance

The FEX Terminal is fabricated from 1mm zentec coated steel primed and finished in a powder coating at high temperatures. As with all auxillary ventilation equipment the FEX will add some resistance to the flow of air. This resistance will then create a slight pressure on the system. This pressure will vary with the amount of air moving through it. The chart below indicates this:

Airflow Performance