Jolo

Thanks, I was wondering what the English name for this sort of floor was! Had a quick search, it does look similar. Luckily I'm not attaching much weight to it, and I'm hoping to not have to drill into it at all, if possible!

Yes, my plan was to frame both side walls, then timbers spanning the gap, as you described. Like a horizontal ladder laid beneath the ducts. The thing I really wanted to check was if I needed extra connections to the ceiling along the middle. I've not done this before, and I know on a larger room I'd need additional supports in the middle. I tried searching but couldn't find what the recommended maximum span might be. I've made a rough sketch -- the red is the wooden ladder, fixed to both walls along the length of the hallway, with timbers spanning the width. The green bits are the thing I wasn't sure was needed, vertical supports connecting the timber spans to the ceiling, along the length of the hallway, in the middle.

Exactly right, Dave. It would also be fiddly to box in the whole wall, so just that part with the pipes is plenty, and as you say it won't make the stairwell feel narrow. So my main worry -- that the 1 metre span across the hallway would need ceiling brackets in the middle -- sounds like something I can ignore! Instead I can just anchor the frame to the wall all around the edge. Thanks!

Thanks both for your replies! Very helpful. And well spotted, there is a gap in the wall where the stairs are, but there will be some pieces of wood coming down there in line with the wall, as the ducts run down the wall above the stairs and will need boxing in too. So my plan is to have some vertical battens beside the ducts. And at the end, connect above the front door. I've taken some more photos, if that helps clear things up!

Now that my MVHR saga is finally over, I'm ready to box in the ductwork. Luckily I was able to route the ducts with minimal damage in the rooms themselves, as upstairs we had big enough ceiling voids, and downstairs all rooms connect off the hallway. But this does meain that the hallway has taken the brunt of the routing -- see photo! Now as this ceiling is pretty high (2m 60cm) I'm not worried about dropping it 15cm or so. It's also an opportunity to add better lighting (currently the only light is towards the back, it really needs one at both ends, or even three). The wall on the left side is wood, and the right side is brick (it's a load-bearing wall), but the ceiling is a bit of a mystery to me. It's either concrete or it might be a reinforced brick floor (1960s Dutch "Nehobo" floor, like a wall made of hollow bricks, with steel bars for strength, laid on its side). But whatever it is, it's a real pain to drill into. I've managed it here and there, but I've also managed to break at least two drill bits in the process! So ideally I'd like to get away with no (or minimal) drilling into the ceiling, if it can be avoided. Though if I have to, it's possible. However the hallway is only 1 metre wide, so my question is, do I even need to drill into the ceiling? If I put wooden battens along each side wall, then cross-battens across the span, will that suffice to hold a single-layer plasterboard ceiling? Or is a metal frame the better/easier option? Or do I really need some sort of support along the middle to prevent sagging? Thanks in advance!

My faulty Brink Flair unit has now been returned, and I bought and installed a DucoBox Energy Comfort 325. All of the problems I attributed to the Flair have now gone away. This is as good a like-for-like test as you're going to get, everything is the same - same house, same ducting, same vents, only the main unit has changed. Just for completeness, I want to mention two additional (objective, measurable) tests I did on the Brink Flair in the last days we had it, using a CO2 and humidity monitor. Why didn't I think of this earlier!! I placed the monitor inside one of the supply vents, luckily we have two through-wall vents which are perfect for this (https://www.ventilationland.co.uk/en_GB/p/uniflexplus-wall-manifold-rear-connection-1x-o90-mm/9744/) so the whole monitor can sit in the incoming airflow. We then left it for a few minutes so the values could settle down and we could get a general background reading: the RH was about 55% and the CO2 was about 450ppm. First test was a humidity test: I boiled a kettle in the kitchen and let the steam be sucked into the extract valve. The RH jumped to 70%, then went back down again. I also showered, and again the RH shot up to 70% (see attached graph). Second test was a CO2 test: I disconnected the flexible noise dampener which is connected to the Flair's extract port, and breathed into it several times. The CO2 reading at the supply vent briefly increased, from about 450 to 485, then went down again. I tried this again with my partner, and the CO2 reading went up to about 540 PPM. (This one is difficult to show on the graph though, as the unit only logs every five minutes, so the brief peak isn't logged. It's difficult to keep breathing into the extract!) This can only be because there was a leak inside the unit. This does echo the results of my smell test, but is more objective and can't be written off as me having some sort of super-nose! I consider that to be proof that the Flair was faulty, despite Brink's inistence that it wasn't. The new Duco works as expected. I've done the same tests, and showering makes no difference at all to the moisture levels of the incoming air. It's been in for over a week now, and the RH in the house hovers around 44 to 54%. Even while boiling a big pan of potatoes there's no moisture on the kitchen window, whereas with the Flair it would be dripping wet. With the Brink Flair the humidity in the house was always high. The 55% mentioned above was only acheived because we had left the above-window vents open, and aired the house out every day by opening the windows for several minutes. Until we started doing that it was always above 60% and would jump to over 70% when cooking/showering. I must say I'm really disappointed with Brink. They showed little interest in the problem, I had to nag them constantly, and were almost totally unresponsive, and it seems they closed my 'case' several times. If I hadn't kept the pressure up they would never have responded. Which is a shame, as I really liked their products otherwise.

Thanks for the tips! The unit goes in a cupboard on the first floor, the difficult bit is the Dutch stairs, which can be more like ladders than anything that would be called "stairs" in Britain. (Though lots of people here have their washing machine in the bathroom which is usually upstairs, I've no idea how they manage it...) However, I went for a Duco Energy Comfort 325 in the end. It seems like a good choice, I like the programming menus, and as it's over-sized for our house we'll end up running it well below capacity, which should be good for efficiency and noise. Although I think I might be cursed -- the first one that arrived had been opened before, and the unit was covered in scratches and paint blobs... so they're bringing us a replacement tomorrow. This will be our fourth MVHR unit since August, hopefully the last!

Oh that's interesting, I've heard differing opinions on the need for a pre-heater. It was one reason I went for the Flair instead of the Ease. We did have several days below zero this winter, but I thought the pre-heater was only really needed below -7 or something? There's a separate external pre-heater available for the Comfort, and there's version called the Premium which has one as an option.

I think I will go for the DucoBox Energy Comfort 325 as it's available now, and is light and compact -- and as its capacity is so much bigger than our maximum, surely running it so slowly will get amazing heat recovery? Also what I wrote last night about the Duco wall-mounted controllers is incorrect, the three ventilation positions can be adjusted (I found it in a separate manual, which goes through all the options in detail). So that's good. Out of interest, I wonder what people's thoughts are on the Itho Daalderop HRU 200 ECO. It's an absolute bargan basement option, available for well under a grand in either Euros or Pounds. I'm amazed at the price! The volume setting is done via two potentiometers, one for low and one for high, the middle speed is just the average of the low and high. https://www.ventilationland.co.uk/en_GB/p/itho-daalderop-hru-200-eco-unit-e-rft-high-rise-200m3-h/9947/

One big reason for choosing enthalpy was the lack of a convenient condensate drain point, but I feel up to tackling that now I discovered the drain pipe saddle clamp things...

Thanks everyone for your input, much appreciated! I'm baffled too, as is the distributor. And I chose Brink as they're well-known in this sector, been around a long time, manufacture in NL and sell globally, and they're part of Ariston. But their customer service has been very poor -- they don't respond until they're nagged, go silent for weeks, they've even ignored repeated emails from the distributor, and apparently told him it was sorted when it wasn't. It took them two months to get around to testing our first (returned) unit, and even then it was only because I'd emailed one of the executives at Ariston out of desperation. They said it met all required norms, yet every house guest who's been willing to try it has scored full points at a game of "guess the odour". Even their installer who came could smell the problem. I've offered to help test it, told them they can send someone whenever and I can demonstrate the issue in 30 seconds. Part of the problem is that we self-installed, so from their side it's the distributor's problem, but he just runs a small ventilation business and whatever commission he made from the sale will have already been eaten up in the time he's spent dealing with this! If he was based nearby he'd probably have come round to smell it for himself, but that hasn't happened as he's almost an hour's drive away. Now I'm thinking about it, I'd have been happy to pay for a visit to test it. Even after all this, if there was a solution offered then I'd rather keep the Flair (or switch to an Ease) than go through the hassle of swapping it out, but Brink seem to have little to no interest in engaging, so sadly I'm out of options. 🤷‍♂️

As mentioned in other threads, I've sadly lost confidence in Brink due to the odour issues I've had with the Flair 200/225. So I'm having to dive once more into the world of MVHR units, and I'm drowning in research now 😵 my head is just swimming with it. I was going to splash out on the Zehnder Q350 with enthalpy exchanger but then I noticed it's almost 50kg, which will be a total pain to install. (I guess I could take the exchanger out to get it upstairs and on the wall...) I do like the look of the DucoBox Energy D325 (and it's smaller sibling the D250, which isn't available until April), but the four-button wall-switch will apparently only do 10%, 50% and 100% of the maximum speed, and that can't be changed?! (Having a 10% flow button seems really strange to me, especially as there's a separate holiday mode. I'd much rather 30% 70% and 100%) I've also just learned that many models of MVHR don't have constant volume regulation, which I think means that the m³/h you set is just a hopeful target, and it will drop over time, which seems a bizarre omission to me. So... does anyone have recommendations, suggestions? (Or brands/models to avoid!) Our house is less than 80m², and the calculations based on Dutch norms came out at a top flow of 175 m³/h. Nothing fancy going on, a very simple set-up really!

Sure! It never worked properly, as there's a leak inside the unit. This means any smells/moisture are just distributed around the house. I've been posting about it here, hijacking an old thread on the same topic, from about halfway down the first page. The ordeal still isn't quite over, I'm waiting for a collection date and refund at the moment (though the distributor has agreed to this). It's a shame, as I really liked the Flair and chose it after a lot of research, but I can't live with the cooking (and worse!) smells being blown into the bedrooms all the time. (I've been closing the vent into the main bedroom when we cook, the transfer is that strong.) If you decide to go for a Flair anyway then maybe yours will be fine, but I advise you to test it straight away. It's fairly easy to do -- just have someone waft a bag of ground coffee or squeeze the air out of a half-full bottle of shower gel near one of the extract valves, and see if the smell comes through one of the supply valves. I'd be very curious to know if anyone else has the same issue we have!

Thank you John! So these units are just missing some logic which adjusts the fan speed depending on the pressure, is that right? BTW I was considering getting a Zehnder Q350 with enthalpy exchanger, but then saw it's almost 50kg!! The Duco 325 is only 21kg, that might be a better option... Both seem to have constant flow, at least!

I'm currently researching options to replace my faulty Brink Flair 225, and have found some which apparently don't have constant pressure or constant volume, which seems bizarre to me. So without that basic feature, if I set the normal flow to, say 100 m3/h, it will drift over time as filters become dirty? Here's an example of one: https://www.ventilationland.co.uk/en_GB/p/vent-axia-mvhr-sentinel-kinetic-advance-250sx-including-preheater-right-250m3-h/9985/