Single Room Vents with Heat Recovery

This may be our next move on our retrofit journey.
There seem to be a number of choices.
Ideally I would start with 100mm diam units because these would be a drop in replacement for our Aereco in-wall vents.
Does anyone have any useful advice on how best to choose 1 of these?
Or direct experience and even better any performance data to go with that?
These are just 2 units available on-line. The Blauberg unit is from a relatively well known brand but what does it offer over the cheaper option here?

I am not familiar with either product but these a a few pointers to consider:

Noise level
Recommended room area/volume
Percentage heat recovery (independently assessed)

Lunos is the name I have always associated with these, and I see they are (apparently) available from Partel at

Perhaps they could be a third option? but I have no experience.

Take a look here:

I have eurovent and Vent axia lo carbon and both are pretty quiet in operation. Please note that the units have to be fitted on a downward outside angle to ensure any condensation drips outside. So before any direct replacement please check for drainage

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Drainage is important. Hopefully the current ventilation is also on the slope, if only to counter rainwater ingress.

I don’t know if you’ve already decided on a way forward with this in the meantime, but in case not:

I have previously used Vent Axia Tempra “through the wall” MVHR units, and have recently installed two of the Blauberg models: one Midi and one Mini. Although it’s early days for the Blauberg units, I can tell already tell you they are in a different league (as reflected in the price!).

The Midi is substantially quieter than the Mini - I would only use the former in a bedroom. Yes, it’s a real pain to install the 160mm dia duct for the Midi, but definitely worth it.

Note the minimum wall thickness required (mine is currently protruding until we do the EWI!).

They actually instruct you to drill an oversized hole, and supply polystyrene wedges to ensure you have a fall in the duct to the outside, in order to address the condensation drainage issue (although I think that’s a bit over the top and I would just get the hole drilled to the right size but on a slight downward slope).

I have yet to network the Blauberg units, which is of course their key selling point. They sell a variant with bluetooth-like wireless connectivity, as well as the Aeris model that I have (and you included in the original post) which requires a hardwired (with a data cable) connection between the units.

The Vent Axia units I installed a few years back have got nosier with motor wear - something to bear in mind with any fan you install in/close to a living space. Only time will tell whether the same will happen with the Blauberg units but given how much quieter they are out of the box, they’ve got a massive head-start in that area…

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I see from a schematic of the unit that the heat exchanger is at the far end, so having protruding ducting could be leading to excessive heat loss around the warm side of the duct. Could you find a scrap of EPS or PIR to fashion a wide collar around the protrusion? Something with a good overlap like this:


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Thanks for this Rob, very useful.
How does the Blauberg Mini compare with the Vent Axia Tempra in terms of noise in your experience?