MJNewton Posted February 5, 2018 Share Posted February 5, 2018 Hi everyone, My first post here so let me start off with a big thank you to past contributors to MVHR discussions - the archives have been invaluable in getting me up to speed with the nuances of numerous aspects of system design and have even provided answers to questions I didn't know I had! I note a number of names were on the ebuild forum too on which I have also been trawling the archives of. One aspect I haven't read much (anything?) about is aesthetic considerations of the room supply/extract valves. I see that there are numerous options available, most of which are subtle variations on the same theme, but I am sure some must look better 'in the flesh' than others not least given that there appears to be quite a range of costs. I was wondering if anyone had any particular recommendations? I think quality and subtlety of finish would likely pass the wife test (the judging criteria of which is, naturally, only to be disclosed once I am past the point of no return with cutting holes!). I wondered if something like the acoustic offerings from Alnor might fit the bill by virtue of them being fairly plain looking and obviously air vents. I think I am perhaps nervous of the commercial look of a conventional valve having seen them in many an office environment? Of course, perhaps it is more that I am over thinking this and once the novelty and focus on MVHR has worn off any valve will blend in to the surroundings along with everything else. Incidentally, I am planning on using HB-type semi rigid ducting and balancing flows at the manifold end with restrictors; non-adjustable ceiling valves would therefore also be acceptable if this gives any more choice. Mathew Link to comment Share on other sites More sharing options...
ToughButterCup Posted February 5, 2018 Share Posted February 5, 2018 Welcome Matthew. You're clearly one of the more discerning types.... most of us here are so worn down by the Hell of self-building, we're just glad to get stuff at a sensible price. So your post is the more valuable for lifting our sights a little. I take it you meant us to understand 'valve' as the bit of plastic that sits on and in the wall at each MVHR inlet and outlet vent? Care is needed because the word valve actuates the brain cells of our resident Welsh Plumber, who is still drunk after the rugby this weekend. Perhaps invisibility has something to say for itself where inlet and outlets are concerned? Anyway, you're most welcome. Ian Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 5, 2018 Share Posted February 5, 2018 Welcome. Using any of the 75mm OD duct systems pretty much locks you in to a limited range of terminals. We used these terminals which are pretty discreet looking and have the advantage that they can be just unplugged by hand and put in the dishwasher to clean them. The rear unit that takes a single duct is this one: https://cvcdirect.myshopify.com/collections/radial-ducting/products/airvalve-90-fitting-92duct-125mm-valve and the terminal that plugs into it is this one: https://cvcdirect.myshopify.com/collections/radial-ducting/products/conus-airvalve-125mm Where we had to fit fresh air vents into a vertical wall, we went for these directional ones, that can be turned to direct the airflow: https://cvcdirect.myshopify.com/collections/radial-ducting/products/turn-airvalve-125mm One consideration is whether you are using the HB+ system where the flow adjustment is at the plenum chamber, using restrictor rings, or one of the other systems where the flow adjustment is at the terminal. The former is quieter, has neater looking pretty flush looking terminals, but is trickier to initially balance and set up, the latter is easier to set up but does mean that you need to be careful when cleaning the adjustable terminals to not upset the set position (and you need to remember where each one has come from so it goes back in the same place!). Link to comment Share on other sites More sharing options...
lizzie Posted February 5, 2018 Share Posted February 5, 2018 Depends a bit on what you want spend really. I have lovely milky glass fittings for my ceiling holes (tech term LOL)but they cost a lot, I figured they were going to be there and visible for a long time so they had to look good. I just couldnt find any others I liked. Various different shapes and sizes available. https://www.fraenkische.com/en/Ventilation/Building-ventilation-for-installers/Systems/profi-air-starline-design-grill/profi-air-starline-design-grill-7228.html Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 5, 2018 Share Posted February 5, 2018 9 minutes ago, lizzie said: Depends a bit on what you want spend really. I have lovely milky glass fittings for my ceiling holes (tech term LOL)but they cost a lot, I figured they were going to be there and visible for a long time so they had to look good. I just couldnt find any others I liked. Various different shapes and sizes available. https://www.fraenkische.com/en/Ventilation/Building-ventilation-for-installers/Systems/profi-air-starline-design-grill/profi-air-starline-design-grill-7228.html Are they adjustable to balance the system, though, or do you have to adapt them to fit a system that has balancing valves/restrictors fitted elsewhere? I spent a fair bit of time looking around and found a fair bit of incompatibility between different manufacturers fittings, which could be tricky to get a work around for. I found that all our ducts needed some form of flow regulation to get the rates to comply with the regs and to ensure that the MVHR worked at best efficiency, and it was a pretty tedious task! Link to comment Share on other sites More sharing options...
lizzie Posted February 5, 2018 Share Posted February 5, 2018 We have the Robbens Frankishe system and they are part of that although they will fit the same size pipes on any system. We have some flow things behind them inside the pipes that regulate the air. These covers are so easy to take on and off they are magnetic just pull on and off really well for easy access and cleaning we also have filters behind the covers on the intakes. Thats about the extent of my technical knowledge sorry! Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 5, 2018 Share Posted February 5, 2018 54 minutes ago, lizzie said: We have the Robbens Frankishe system and they are part of that although they will fit the same size pipes on any system. We have some flow things behind them inside the pipes that regulate the air. These covers are so easy to take on and off they are magnetic just pull on and off really well for easy access and cleaning we also have filters behind the covers on the intakes. Thats about the extent of my technical knowledge sorry! Sounds like a neat solution. Most of the flow adjustment systems are either clunky (like running around changing restrictor plates) or mean screwing the actual terminal in and out on the thread, so they all end up looking slightly different if there's a lot of adjustment. For a budget solution I think it's hard to beat the ones I linked to, as they are very unobtrusive, especially as so few people gaze up at the ceiling all the time, where 90% of them are fitted. Here's a view of one in the corner of one of our rooms, The outer ring that sits flush with the ceiling is around 150mm diameter: 4 Link to comment Share on other sites More sharing options...
MJNewton Posted February 5, 2018 Author Share Posted February 5, 2018 (edited) [Apologies for those that got a half-complete notification - I somehow submitted without having finished] Thanks everyone for the welcome, and indeed the comments/suggestions. Addressing some of the key points raised: Terminology - Yes, if I've found one thing with MVHR it is the variety of terms in use often interchangeably! I am seeing manifolds and plenums being swapped around; and valves, terminals, grilles, vents (and now 'ceiling holes'! ) all being used. Here am indeed talking about, well, the ceiling holes (that's arguably the least ambiguous term given its uniqueness!) System Type - I am intending on using the HB+ system with the central manifold-based flow restrictors (based on your previous discussions/experiences with them JSHarris) and accept that initial balancing is going to be a bit of pain. Having performed a 20-stage iterative balance of our wet central heating system, taking around 6 hours to complete, I've got the determination (and OCD?!) to see something like this through though! It may well end up something of a hybrid system of different suppliers where possible/compatible and I *might* make my own manifolds to suit my specific needs (and budget). Something worth mentioning is that this will be a retrofit installation and whilst it will be performed alongside a new extension it does mean I can afford to be a bit more focused on some of the arguably less(er) important aspects! As you say, Ian, a complete self-build must mean any available time is highly competed for and so I could well understand that subtleties of vent aesthetics are justifiably low down the list! The fact that I am retrofitting means that wherever possible I shall be wanting to install from the below-ceiling side (just to be clear: the ducting will be in the ceiling void; it is just which side I'll be primarily working from!). For this reason I may well end up fabricating my own plenums that I can fix from beneath using a 63/75mm-to-125mm adaptor and 125mm right-angle rigid bend as all plenums I've seen are very much fit-from-above or at first fix. I think I'll be able to do all this from underneath (I've done similar before with an inline shower extractor fan) given the right terminal type (particularly the ones with a collar that is screwed to the ceiling hole edge. The Conus air valve is not one I'd come across JSHarris but could be just the ticket given how slimline it is and depending on how easily I can attached it to a non-HB+ plenum. Am I right in assuming that there's no distinction between supply/extract with that particular type? The type Lizzie has also sound very interesting, but my desire for (expensive) aesthetics is unfortunately sometimes countered by my thrifty-Northern roots so I might have to avoid looking too much into that option! Edited February 5, 2018 by MJNewton 2 1 Link to comment Share on other sites More sharing options...
Ferdinand Posted February 6, 2018 Share Posted February 6, 2018 Thanks for the reply - nice to see threads wrapped-up. Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 11, 2018 Share Posted February 11, 2018 On 06/02/2018 at 04:30, Ferdinand said: Thanks for the reply - nice to see threads wrapped-up. On 05/02/2018 at 15:58, recoveringacademic said: Care is needed because the word valve actuates the brain cells of our resident Welsh Plumber, who is still drunk after the rugby this weekend. Just to fully wrap it up, I wasn't drunk, just tainted slightly. 1 Link to comment Share on other sites More sharing options...
Onoff Posted February 11, 2018 Share Posted February 11, 2018 Daft question..... I am since day one, considering a single room MVHR for the bathroom. As in a the wall type Ventaxia. I've not really got the wall space though where it wouldn't stand out like a sore thumb. Should I maybe be thinking about a couple of ducts on the ceiling and a loft mount MVHR. Maybe something I can expand later on as I do the other rooms? Link to comment Share on other sites More sharing options...
j_s Posted February 11, 2018 Share Posted February 11, 2018 I don't see why your can't just get a loft unit and as you improve each room , add another duct run Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 12, 2018 Share Posted February 12, 2018 8 hours ago, Onoff said: Daft question..... I am since day one, considering a single room MVHR for the bathroom. As in a the wall type Ventaxia. I've not really got the wall space though where it wouldn't stand out like a sore thumb. Should I maybe be thinking about a couple of ducts on the ceiling and a loft mount MVHR. Maybe something I can expand later on as I do the other rooms? That would work. Just adjust the fan speed right down initially, then gradually turn them up as you add other rooms. Much of the cost in MVHR is in the ducting and terminals, so it might not cost that much more to do this now, plus you'd have the advantage of being able to add MVHR to each room as you go just by adding a bit of duct and a some. The only downside I can see is that you ideally need to run MVHR ducts in pairs, to keep the system balanced, so initially you would fit an extract duct in the new bathroom and fit a fresh air intake duct in one of the living areas. Link to comment Share on other sites More sharing options...
MJNewton Posted February 12, 2018 Author Share Posted February 12, 2018 @Onoff You will also likely see (or hear!) the benefit of reduced noise by siting the MVHR unit within the loft space. Link to comment Share on other sites More sharing options...
Onoff Posted February 12, 2018 Share Posted February 12, 2018 3 minutes ago, MJNewton said: @Onoff You will also likely see (or hear!) the benefit of reduced noise by siting the MVHR unit within the loft space. Cheers. (I was trying not to detract from your thread btw) Loft is the obvious option but at the mo that is cold space. Link to comment Share on other sites More sharing options...
MJNewton Posted February 12, 2018 Author Share Posted February 12, 2018 That's alright - I'd got everything I required, and your query was on-topic by virtue of the aesthetics angle. :-) Regarding the cold space, others with more knowledge will chime in I'm sure if I've got this wrong, but my understanding is that the performance and efficiency of an MVHR is indeed affected by external heat loss/gain, and consideration must also be given to avoiding condensation forming. You should therefore ensure that duct runs and the unit itself are well insulated when located outside the thermal envelope of the building - I don't imagine this is all that difficult to achieve within a loft space using conventional loft insulation though. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 12, 2018 Share Posted February 12, 2018 I think the best loft installation I saw (can't find the link now, it's not on this forum) was the chap that made a big box out of PIR foam with a large PIR access panel that just plugged into the front of it. The MVHR was in that, together with the plenum boxes, and all the ducting ran down and under his loft insulation. Seemed a pretty good way to keep things neat and tidy as well as insulate the unit. IIRC he used the tile grill external terminals, and ran the intake and exhaust ducts vertically up to the roof from the big PIR box. Link to comment Share on other sites More sharing options...
j_s Posted February 14, 2018 Share Posted February 14, 2018 I will take some pictures of my mvhr in the loft soon. I'm building an insulated board box for the unit itself out of 100mm celotex. Might even get to switch it on soon! Link to comment Share on other sites More sharing options...
Adsibob Posted February 5, 2021 Share Posted February 5, 2021 On 05/02/2018 at 17:52, lizzie said: We have the Robbens Frankishe system and they are part of that although they will fit the same size pipes on any system. We have some flow things behind them inside the pipes that regulate the air. These covers are so easy to take on and off they are magnetic just pull on and off really well for easy access and cleaning we also have filters behind the covers on the intakes. Thats about the extent of my technical knowledge sorry! I'm interested in the Robbens Frankishe terminals that @lizzie has, as I think they will work really well with our interior decor in some rooms. I see from their website that these pretty terminals are compatible with the following size radial ducts: I think the difference between those two diameters must be internal and external diameters, but that would mean the duct is between 10mm and 13mm thick. My question is what airflow rate do I need? Or will i need different sizes for different rooms given it depends on the volume of the room it is extracting or supplying from? Maybe it's a silly question, but I note that airflow rate is hardly mentioned when choosing ducting, only when discussing the actual MVHR unit - surely the airflow of the ducts is just as important? Link to comment Share on other sites More sharing options...
dpmiller Posted February 5, 2021 Share Posted February 5, 2021 generally one 75mm duct will flow enough to the average room, running two ducts to each plenum offers increased flow or reduced noise, as required. Link to comment Share on other sites More sharing options...
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