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 https://www.partel.co.uk/product-category/lunos-ventilation-with-heat-recovery/
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?
@zapaman Sorry for replying so late - I only just noticed your followup question! Even the Mini units from Blauberg are noticably quieter than the Vent-Axia Tempra.
No direct experience but this guy seems to have a good handle on the topic.
My conclusion was that you had might as well use a low speed extractor.
Charlie DIYte
Low speed with a boost function.
However:
As he said, centralised MVHR is the best if you can afford/fit it.
Luckily for me I have three rooms with built in wardrobes, each of which now have ducts taking fresh air to the ground floor from the loft. There is no way that I would live without MVHR now.
“Air quality” for the purpose of these graphs is VOCs
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Yeah, we had an MVHR installed 3 years ago in our terraced house and managed to cramp most of it in the loft with piping going through the little store room on the first floor down into the kitchen. So not too much disturbance.
We don’t have an air quality monitor, but since I now live part time in another house without it, I just notice the difference in air quality each day.
I mean the price of the single room MVHR units seems enticing compared to a full house unit, but I am weary of cutting 160mm holes through my walls in every room. Also from a cost perspective in a whole house retrofit, the MVHR was good value for the benefit, because it was just about half of the cost of installing all the triple glazed windows and doors.
I think if you can afford it, plan in a whole house unit. However, of course if you can put the small units where would you put them as a priority? I wouldn’t be able to decide between bathroom, kitchen, bedrooms, living room. You really need one in every room, don’t you? Where do you ave yours @rob and what are your thoughts. Your experience would be great as you do seem to have multiple. Do you have any airtightness issues with these?
Does anybody know what the EPC evaluation would say to these? Is it the same issue as with a whole house unit i.e. a significant downgrade?
The downgrading of EPC with a centralised MVHR is based on it being always on extraction. The distributed units are also always on but [edit: some of them] only extract half the time.
But would the EPC assessment differentiate?
Does it really matter what the EPC says? The calculation method may be changed again. Better to stick with a model that actually measures usefully, like PHPP.
If your house isn’t likely to hit high levels of airtightness you might also consider a dcMEV (dc=demand control) unit. Less ducting (because it only extracts) and a lot cheaper. Look at Aereco.
Unfortunately, yes, it does matter what the EPC says. It is the metric used by the government for all sorts of functions and the general public have never heard of PHPP.
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I meant in the context of the OP’s requirements. I agree if you have to get a grant or something that depends on it. But I also think we should avoid chasing EPC points when it’s a pretty poor judge.
Early next year we should be getting an all new EPC procedure. I will be looking for a new EPC after that. I should see a big improvement. My HP & MVHR should become benefits rather than liabilities.
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Would be great to see an updated EPC, but I wonder if it will get further delayed than next year.