GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Are Fi-Wi or Fine Wire Ventilation systems for a Passive house adequate or hyped up?

ThXzr7FgXL | Posted in PassivHaus on

As the question implies I wonder if any one here has any thoughts on this ventilation system I have come across on a particular site in Ireland. Here’s a link to it

Here’s an extract –
“FiWi HRV has revolutionised the way we ventilate Passive Houses because it’s super efficient, it eliminates complicated duct runs that require regular cleaning… Water Vapour and CO2 levels equalise rapidly in air at speeds of + – 500m/sec so they don’t need to be chased around the house with ducts, by lowering the levels in one area, Humidity and C02 from other areas rapidly rushes in to equalise, vents over bedroom doors facilitates this. 2 strategically placed units become the lungs for a house, 20 degree stale air exits and 19 degree fresh air returns simultaneously through each unit. Cool fresh air does not mix with warm stale air but the heat is efficiently transferred from warm -> cold through the Fine Wire heat exchanger. Each FiWi HRV unit at medium speed (150m3/hr) can exchange enough air for 5 people, one person requires 25m3/hr, but at the higher setting one unit can exchange 250m3/hr. The EC fans have capacity to move 1,000m3/hr so they can be used to control overheating in Passive Houses when temperatures exceed 24 degrees” and

“The surface area of a Fine Wire heat exchanger is 10 times greater than a similar sized standard plate heat exchanger allowing for greater efficiency. A FiWi HRV unit can be built into a wall at the build stage. It can be built into your fitted kitchen and uses a standard 30cm x 72cm fitted kitchen door… It can be fitted discreetly into your fitted wardrobes in a bedroom etc…. For a regular house one unit is fitted in the living area and another in the upstairs landing, the bathroom is ventilated with a humidity controlled fan that automatically opens the duct. Power consumption (6W/motor) is extremely low from the 2 long life EbmPabst fixed magnet EC motors.

(Using Various thermostats)…FiWi HRV compensates for weather conditions while the efficiency of other HRV units drops below 70% when the wind blows. CO2 and Humidity monitors are fitted as standard to each unit to maintain air quality. There is no duct work requiring regular cleaning and the easily removed Heat Exchanger can be regularly washed in your dishwasher or under a shower… FiWi HRV is the most efficient heat exchange technology on the market with each Heat Exchanger containing 20km of 0.10mm copper wire as an exchange medium, making the surface area 10 times larger than most other HRV units on the market.”

Are there any similar systems in North America? Is this only suitable for simple, large open plan arrangements? Have heard discussions on the prototype model that was tried before this by another company and the Power output was a serious issue then, as was ability to actually dry a modern bathroom quickly on its own (Usually tiled ceiling to floor and covered in condensate after a shower)…

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Martin Holladay | | #1

    I'm not familiar with this type of HRV.

    Can any GBA readers help Tim out?

  2. user-1088066 | | #2

    I have been to Ireland and had experienced the FIWi HRV. They work with point source cascade ventilation and the measured efficiency I saw were between 75-80%. They do work well, although Seamus is still perfecting them. The technology is very neat and quite affordable, just not really available in the US yet.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |