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  1. We're planning on using our attic space as a playroom and I can't work out whether the temperature will be balanced or if it's going to be too hot up there in the summer and too cold in the winter. The house is an MBC build (0.11 walls, insulated roof and slab) which is currently in build, with triple glazed alu-clad windows (which are fixed apex windows in the attic). We're putting UFH on the ground and first floor but nothing in the attic. The MVHR unit is going up here so we can add vents into this space and there will be a number of rooflights, probably double glazed. Will this be enough to create a usable temperature up here? If the whole house is 3G, are we made to put double glazed up here (to cut costs)?
  2. I am planning the design for our new build and have created a nicely sized plant room on the ground floor. In our last build, our MVHR was put up in the loft and this appears to be a very standard place. However, it was horrible to get to to change the filters and more importantly, in this build we are having a flat roof so no lofts in sight! Is there any possible reason why the MVHR cannot go downstairs? If the intake and exhause vents need to be at first floor level, is there normally any resitriction on the length of pipework? We haven't even looked at MVHR units yet so checking the spec of "our" unit isn't possible. If there is no reason not to put it downstairs, am I missing something in wanting it accesible? I know you only change the filters once or twice a year ( not sure because I am not the one who would venture into the loft to do the deed), but it just seems to make better sense to me. It also caused us lots of issues when it came to doing the air-tightness tests at the end. We have learnt a lot from that build which was lovely to live in but cost a fortune to heat.
  3. My distribution box for the MVHR ( sometimes called spigot box or manifold) will sit beneath a flat roof , but above a ceiling. The roof build up from top down is; Alvitra Avalon over 270mm of insulation on some super expensive vapour stuff - forgotten the name - the price was so traumatic 22mm OSB3 POSIs above the ceiling build up which is Vapour control layer 25mm insulation 12 mm plasterboard 2mm plaster skim. There's enough space for spigot boxes to sit comfortably under the POSIs. That means they are outside the heated envelope. (just) The supplier says not to worry : but they would wouldn't they? Everyone has that problem, said the rep, What do you think?
  4. Hi. Firstly, not sure this is the correct place to post... never seen so many sub-forums in my life.... We're building a 245m2 passive(ish) house this year. South facing, plenty of solar gain when need (bris soleil and external blinds to minimise when not wanted). We're in a town and on mains gas, so it seems by far the most logical source of energy for heating and hot water. As much as I want to de-carbonise, a heat pump doesn't make sense in our case. So, that part is sorted. As we'll have triple glazing, ICF walls, large thermal mass, high air tightness, our energy demand will be low. I don't see the point in spending thousands installing a central heating system. Plus we'll have a wood burner - will be rarely used, so not fussed if there's a back boiler on it. Our initial PHPP assessment attached. I'm thinking plumbed towel rads in wet rooms and maybe 2kw post heaters (3x 150mm - one for each level - each with own control e.g. central warm water heater) Any issues with the above? Would also consider electric under tile heating mats for the master en-suite for my other half's chronically cold feet... My main query is hot water.... there's just the two of us and we both travel a lot for work so we've no regular routine. We have a combi boiler in our house which is great.... but hate the long delay for hot water to come out of the tap and the massive pressure and flow drops when somebody else flushes a toilet or turns on a tap. So I'm ruling that out. I'm also planning on a 3-4KW PV system with solar diverter to provide hot water in the summer... so that means some sort of storage. What are my options? In summary, we need instant DHW on demand, high flow rates, low running cost, heatable by gas and PV. Thernal store, unvented HW cylinder or sunamp type storage? Really unsure!!! Thanks
  5. I am a new member at the planning stage of a new build house for our retirement and looking to make it as comfortable, efficient and maintenance free as possible. I am trying to get my head round the many and various heating options – things have changed beyond recognition since we built our current house 35 years ago. The plan is that we will have one large room incorporating living/kitchen/dining. This will be on the first floor with ceiling at roof height and extensive glass to S & W to maximise the views. I know this isn't ideal, but we love the outdoors and the views are spectacular. Bedrooms all ground floor. My current thinking is to have wet UFH in concrete screed floors on both levels; either GSHP or ASHP (current preference). Can the ASHP be located in an outbuilding to avoid noise issues? My main concern is solar gain:- Can I utilise this free energy to heat the lower floors/DHW in winter (MVHR)?? How do I keep it cool as we experience the ever warm summers we are promised? (MVHR/AC/??) Thanks in advance
  6. Is it me, or does the requirement to fit fire rated doors upstairs (in our case FD30) mean we can't have MVHR? (Because of the gap under the door for the MVHR). Please tell me I'm wrong. Please tell me I'm overthinking! Reviewing current threads on and around the subject of fire doors, nobody seems to have pointed out that MVHR and FD30 doors are incompatible. Yet common sense says they ought to have door auto closers on them (but that requirement has been removed @PeterW here ) , but it seems obvious to me that a fire door with a gap under it is about as useful, well, as a chocolate fire door. I've reviewed Approved Document B, and the table on page 64 seems to suggest we could use an FD20. Both our bedrooms have a suicide door in them, (with a Juliet) so I suppose it might not be too bad.
  7. Reaching the final straight, need to purchase the main MVHR unit. Was originally going to get an Adroit DV110 but the prices have rocketed, the Kinetic Advance SX looks a strong contender, however the limited reviews of the App on the Apple App Store do not seem very favourable... A key feature for me is being able monitor and interact with the MVHR when away from the property, (new build is over 100 miles away from main house) I've seen the Adroit in the flesh and used the 'cloud' function and whilst clunky it does what I need. Anyone actually got a Kinetic Advance SX, how are you getting on with it and the app?
  8. I found some mention of this in other posts but not my specific question. Now that the hot weather is back I have noticed that on occasion the master bedroom in our current house is a little uncomfortable at around 25C although opening the windows soon fixes this. In the new place the master bedroom has a lot more glass, basically a west facing glazed gable and insulation levels are higher. This got me thinking should I consider "comfort cooling" which I often see advertised on flats in London. I believe that @JSHarris has this on his MVHR, I think via running his heating in reverse? In my case I would have to change the MVHR unit to one that allows cooling. It is partly an attractive option because we will have 3 MVHR units (Dantherm) but one supplies the most used rooms in the house with the most glass so I would only have the extra cost of changing that one unit. I spoke briefly to the heating engineer and he felt it wasn't worth it as there would be an considerable increase in costs because we would have to also up spec the pipework to allow for the possibility of water condensing in it. It would effectively have the same costs as putting in an AC system. He felt that summer bypass is enough, certainly in Scotland it would be rare for the actual outside air temperature to be well above 20C, especially in the evenings. Also we can always open the windows. If this isn't enough he recommended looking at solar reduction film for the windows or a through the wall AC unit. Does anyone have any thoughts or experience of using comfort cooling and how well summer bypass works in practice?
  9. Hard hat on. It is possible to run MVHR ducting through a passive slab? I am starting to think about ducting runs from my bungalow with vaulted ceilings. As a bungalow, there are no joists to take the runs. Passive slab not poured for another few months at least.
  10. Fitting my vent terminals for my Mvhr supply and extract valves and I know a few on here have used BPC for the ducting etc. When cutting the plenums down to size, the bit that sticks through the plasterboard that the ceiling valve pushes into, have people left them to protrude a little bit lower than the plasterboard? It is just when I looked at how the valve attaches to the plastic tube it needs to compress a foam gasket and I assume for this to work properly it would need the tube to be left longer than the flat surface of the p/board to make a snug fit? TIA
  11. Hi guys, Just joined this group. Just finished building a Passivhaus in Penzance, Cornwall. My friend and I built 2 houses together, one for each family on a challenging plot chasing the passivhaus dream... We've been in the house since end July and just seeing how it copes with our first winter! So it's a timber. Frame design, sitting on a concrete raft (on 30cm insulation!) planned using the PHPP software to conform to PH standards. So it's super insulated, airtight (0.3ac/hr) no cold bridges, triple and quadruple (skylights) glazed with Brink MVHR system (ubbink plastic duct and plenum). My friend developed the wall buildup himself to achieve the PH standards without us having to buy premade PH timber frame sections, saved us a lot of money... Biggest struggle so far, trying to get the. Brink post heater to operate... It's wired up correctly but won't operate, even at high fan speeds...? Which is really why I joined this forum, to hopefully glean some info as our supplier hasn't solved it (or Brink at this stage!) Cheers.. Murray
  12. I need to improve the ventilation of my own house (2009 chalet bingalow conversion, done to roughly 2010 regs), as it now needs to run slightly warmer for parent comfort reasons and is starting to feel a little stuffy (need to check humidity). In theory I could fit an MVHR, but it is a warm roof chalet bungalow conversion so that would be more than a little complicated, and also of course it would be a big disturbance. The plan is to try: 1 - a PIV unit upstairs - which will be on a wall on the landing not a ceiling with the unit in a space behind a stud wall in the roof angle, as nearly all the ceilings are sloping and if I get into the tiny roof voids it will be very tricky outside. 2 - Replace both upstairs and downstairs bathroom fans with (100mm) dMEV fans. 3 - If necessary trim a few mm off bathroom doors. I would welcome any comments. I am not expecting a transformation, just an improvement. I routinely fit PIVs in rented properties, and a HR fan somewhere downstairs, and all of the installations have worked well. Any comments would be most welcome. Cheers Ferdinand
  13. In the most recent Passivhaus Trust newsletter (link below) is a link to this document, "Good Practice Guide, MVHR for single dwellings". Its a detailed description of how to design an MVHR system for a Passive House. The guide: Papers/2018 MVHR Good Practice Guide rev 1.2(1).pdf The newsletter:
  14. I’m looking to control the losnay MVHR system with some wireless humidity switches - similar to wireless temperature sensors. Does anyone know of any good ones? R ed
  15. This weekend is MVHR install weekend (hopefully). We are looking for some pointers from anyone who has installed a Vent Axia Kinetic Sentinel unit. BCP has supplied all the kit. Very thorough. Could do with an idiots guide for the plan of attack though. First attempt at a plan. How does this sound? 1. site manifolds 2. Site plenums 3. Cut duct lengths and join between manifold and plenum (cutting holes in walls and floors as needed) 4. Site unit 5. Figure out how to connect all those silvery pipes from the unit to the manifolds 6. Put in pipes to outside Is this a reasonable approach? We have trawled this site for photos. Any out there that show all the connections to and from the unit itself and the manifolds? It looks like it should be fun (or the makings of a divorce) 😉
  16. Hi All - i think the filters on my mvhr unit need changing. I’ve just read the manual and it says they should be replaced every 12 months but I’ve only been in my new home 5 months and the machine sounds like it’s having to work quite hard. It’s gotten much noisier. My sustem is Vent Axia Lo Carbon Sentinel Kinetic V MVHR system. I tried to hoover the current filters this evening but it’s a really tough task with little success. Does anyone one know where I can buy replacement filters from for cheap?! I’ve looked online and they all seem really pricey. If you have to change them regularly then it’s really going to add up! Any advice would be really helpful. Also, I’ve seen online that there’s different grades of filter quality. Can you really tell the difference? Thanks
  17. What is this thing doing that a water trap does not? Thanks
  18. Blowing a gale but sunny so giving the mvhr unit is 12 month clean. Not too bad. A few flies in it though.
  19. Hi everyone, I'm pricing and speccing MVHR units with both BEAM and BPC in Northern Ireland at the moment. I'm having a hard time deciding which system is right for us and tbh I feel like I'm dealing with two really salesy sales men, making it hard for me to know if I'm being steering down the garden path. Beam are telling me Rotor is the best and I'm silly to go for Counterflow. They are recommending x2 Counterflow units or x1 Rotor Unit for my 288m2 self build. BPC have told me I'm being taken for a mug and they have recommended x1 Counterflow unit. The BPC unit will be running at 30% capacity and the BEAM unit/s are sitting closer to 50%. I'm totally lost and have to decide pretty soon as to which is best. I'm happy to share spec sheets and pricing etc with anyone privately (not a fan of putting quotes up for everyone to see lol). Any help would be mega appreciated ?
  20. I'm probably a bit late, I am in the middle of a self build and am looking for advice. I have 240 m2 of floor space and have opted for UFH for the ground floor which I have purchased from NuHeat with Neostats. Upstairs I have aluminium Rads with a neostat on the landing and a 300 UV cylinder again with a Neostat all of which are hard wired. I have natural gas and am looking at a modulating Worcester 34kw system boiler. I have a 4kw pv system (SW facing and hopefully will fit an immersun) with single panel optimisers and a Beam c130 MVHR system. I have installed the first fix myself and am looking for any suggestions/advice on things I may have missed. I think I am down to about 0.17 on the external walls with 140mm batts and superfoil, osb before plaster board and also used the foil breather membrane on the external timber frame. A Scan 58 log burner has also been purchased as I am looking at cutting down on bills the closer to retirement I get ? . Dare I venture into the AV/networking!! I am dreaming cables at the moment!!! Thanks in advance C
  21. Hello, Suspect a few of you have faced this challenge with your mvhr system. Is there a certain distance the kitchen mvhr extract plenum to the cooker hood/hob? Is this the direct distance? Or the horizontal distance from directly above the hobs? Would 1m be enough? I've tried finding an answer on line / in my various folders but no luck. What have you all done about extractor hood? Just use a recirculating one? Cheers CC
  22. This post covers more than just MVHR, but I wasn't quite sure where this post would be best placed. Admins feel free to relocate if need be! As you can probably guess by this post going up late on a Saturday, I've been doing a lot of modelling of our heating and energy systems for our house. It has taken a while to get the model to accurately reflect reality, but I think we've finally nailed it. Whilst not surprising, what it has clearly established is that: PV is a no brainier, provided you have the capital up front! Though that's another topic all together (posted here). The MVHR bypass will be insufficient to counter the solar gain during the peak summer months. It's often said that the biggest problem with passive houses (or near passive as our's is) isn't the heating, but the cooling. They're right! Thankfully we have opening windows and plans to use a canvas above our pergola to shade some of the southern windows. So more our of general curiosity, what else have people done to keep the tempretures stable and comfortable during the summer months?
  23. Apologies I didn’t take many pictures of the process. Initial Frustrations: Due to a delay in the First Floor (FF) Micro Screed, couldn’t access the house as planned (Thursday after arrival) but had to wait until the following Wednesday, I would have had the balancing complete by the Monday and had a week to do other small jobs, as it was I got the job finished, bit nothing else. First of all I fitted the ground floor vent terminals, this involved trimming the terminal ends level with the plasterboard Fitting the metal connecting terminal with the supplied Tek® Screws and inserting the terminal: Tek® Screws are a pig, you need to predrill the metal to use the effectively and I was using the builders impact driver Makita 18V LTX and it was still hard work. I locked all the terminals in the fully open position and inserted them, hold up and turn to lock in place, these are an update on the spring clip versions as apparently they don’t get a good seal, with the mechanically fixed base plate and a turn to lock valve they are more rigid, true but harder to install! Installed extract valve. Valve removed leaving housing Housing on adaptor. The first picture shows an installed extract terminal in the Airing Cupboard. The second one the metal connector plate (in the Dining Room) with the valve removed. The third one an adaptor plate attached to the duct terminal in a room that will have a suspended ceiling (tiles) so to be finished after all messy work, the duct terminal will be adjusted as required. Then I installed the FF terminals, I had help for this then access to the attic to connect up the external supply and exhaust ducts to the roof terminals, my builders had to cut 2 access holes in the plasterboard (attic already plastered) one to connect the FF supply duct (the attic has insulation between the rafters and below which follows the vertical chords of the attic trusses) so this duct has less insulation that the others but is still in the insulated area. The second to access the FF exhaust manifold, in the same area (but always planned) these will have insulated doors re-fitted. They also had to cut free the exhaust duct for the FF unit which the plasterers had plastered around, half covering (I ask you), ie 180mm circular duct with half the duct (a semicircle) inside plaster, half out! So I connected up the FF units and proceeded with that one, it made it easier accessing the manifolds before installing the GF ducts. We also had to build a small trestle to go over the FF exhaust duct to lie on to work in the exhaust manifold. Next, I fired up the FF unit and set the speed to 275m3/h, this was a challenge as the electrician had to make certain circuits live. In the CU the top Right is the lift (3-Phase) required for install T&C, the bottom 5 (left) are the MVHR and others on the circuit, 2 x downstairs power circuits and 2 others I don’t know and didn’t dig into. A lot of work still to be done there, but I had my power. The two MVHR units connected up (though the drains weren’t connected until Friday). I then did my initial measure, I have purchased a Testo 417 with hoods and UKAS calibration (belt and braces), whether I keep it or sell on, not sure yet. Initial readings gave a total extract of around 275m3/h but supply of nearly 375m3/h, so obviously my systems measure from the extract and just run the supply at the same speed, the calculation showed similar resistances for the system, so I had to adjust the system (use the imbalance) to even out the flows, initially I used a 100m3/h imbalance to even this out (reduced later on). I then proceeded to balance the terminals, as mine is the Ubbink system the balancing is done in the manifolds with restrictor rings, you have either no restrictor, or a restrictor with 0-12 rings removed (0 = max resistance, 12 = almost no restistance). The table below shows room, terminal, design flow rates, calculated restrictors and the final ones I ended up with. Design Flow Rate BR Min Initial Final Final Room m3/h l/s l/s Rings Removed m3/h Rings Removed m3/h l/s m3/h l/s en-suite 2 E1 45 12.5 8 6 6 23.0 6.39 48.6 13.5 en-suite 2 E2 6 6 25.6 7.11 en-suite 3 E3 45 12.5 8 6 6 24.1 6.69 51.3 14.3 en-suite 3 E4 5 6 27.2 7.56 Cistern E10 20 5.6 - - 12.0 3.33 12.0 3.3 Attic EA 25 6.9 6 10 - 22.9 6.36 22.9 6.4 A/C E5 25 6.9 6 5 5 27.9 7.75 27.9 7.8 Bathroom E6 45 12.5 8 4 4 24.2 6.72 48.8 13.6 Bathroom E7 4 4 24.6 6.83 mstr en-suite E8 50 13.9 8 7 7 27.9 7.75 54.7 15.2 mstr en-suite E9 6 6 26.8 7.44 Cistern E11 20 5.6 4 10 12.6 3.50 12.6 3.5 275 76.4 278.8 77.44 As you can see it was reasonably accurate. I had to reduce the resistance to the attic and one cistern and one other terminal, otherwise quite easy. So with the extract done I moved on to the Supply. Initially I went round and totaled up all the supplies and kept adjusting the imbalance until the total supply was about 275m3/h, which was around 70m3/h, then I set to work adjusting the flows: Design Flow Rate BR Min Initial Final Final Room m3/h l/s l/s Rings Removed m3/h Rings Removed m3/h l/s m3/h l/s Bed 2 S1 50 13.9 11 7 26.1 7.25 50.9 14.1 Bed 2 S2 9 6 24.8 6.89 Bed 3 S3 50 13.9 6 - 19.8 5.50 49.0 13.6 Bed 3 S4 5 6 29.2 8.11 Bed 4 S5 50 13.9 7 4 24.0 6.67 49.3 13.7 Bed 4 S6 6 4 25.3 7.03 Bed 5 S7 50 13.9 6 4 24.5 6.81 50.7 14.1 Bed 5 S8 7 5 26.2 7.28 Master Bed S9 50 13.9 - - 24.8 6.89 49.6 13.8 Master Bed S10 9 7 24.8 6.89 Attic SA 25 6.9 9 - 26.2 7.28 26.2 7.3 275 76.4 131.37 275.7 76.58 AS you can see the difference between calculation and actual is huge, take terminal S3, it has a relatively short run (compared to others) yet I had to remove all restriction and could only get 20m3/h, I balanced up the room with S4 but a total mystery. S1 was a significantly long run but require more restriction than calculated. I managed to balance up the system after several hours of too and frow, including slightly adjusting the imbalance to get the system set. The Ground floor was a similar experience, though with some terminals suspended in the air, the measuring hood neatly sealed over these so measurement was not an issue, and in fact I didn’t need a ladder to reach these ones so it made it easier. GF setting was 220m3/h (I actually set 225) and again the extract tallied up but the supply was about 40m3/h over so Imbalance require again. Design Flow Rate BR Min Initial Final Final Room m3/h l/s l/s Rings Removed m3/h Rings Removed m3/h l/s m3/h l/s Kitchen E1 80 22.2 13 - - 44.0 12.22 85.8 23.8 Kitchen E2 7 6 41.8 11.61 Laundry E6 50 13.9 8 4 6 26.6 7.39 50.7 14.1 Laundry E7 3 5 24.1 6.69 en-suite 1 E4 45 12.5 8 2 6 27.7 7.69 51.4 14.3 en-suite 1 E5 2 7 23.7 6.58 WC E3 25 6.9 6 3 5 26.1 7.25 26.1 7.3 Cistern E8 20 5.6 1 - 11.0 3.06 11.0 3.1 220 61.1 225.0 62.50 Again extract calculation and actual weren’t miles apart, except from I had to remove all restriction from the cistern extract, and subsequently most of the others to balance it out but relatively easy and logical. Design Flow Rate BR Min Initial Final Final Room m3/h l/s l/s Rings Removed m3/h Rings Removed m3/h l/s m3/h l/s Lounge (1) S1 50 13.9 9 4 25.7 7.14 51.8 14.4 Lounge (2) S2 7 - 26.1 7.25 Dining S3 30 8.4 - 3 30.1 8.36 30.1 8.4 Front Hall S8 25 6.9 9 3 26.2 7.28 26.2 7.3 Bed 1 (1) S6 45 12.5 6 12 22.1 6.14 45.6 12.7 Bed 1 (2) S7 6 0 23.5 6.53 Study 1 S5 35 9.7 12 1 35.8 9.94 35.8 9.9 Study 2 S4 35 9.7 - 2 36.1 10.03 36.1 10.0 220 61.1 131.37 225.6 62.67 Supply was another question, nearly a whole day to get this right: Study 2, the longest run yet only 2 rings removed, same for study 1. The Bedroom similar runs one with full restriction and one with almost none. The lounge S1 in longer than S2 though has more restriction required, nothing made sense, eventually balanced, but no rational explanation as to why. The only think I can think of (and this applies to the First Floor) the calculation programme works for the extract system, but for supply, the location of the duct on the manifold has a huge impact on the initial resistance and flow rates. Advice for balancing when doing this go for bold alterations in restriction, I kept nibbling on the GF and have ended up with lots of spare restrictors of various sizes, instead of a load of complete (new) ones. The final thing I did was remove all the vent terminals so the builders could fill in the larger holes and the painters get on with the final job.
  24. Hi, I spotted an opportunity to save money a while back and in areas where we are not using the space all the way to the roof I changed from PIR insulation between the rafters to rockwool above the ceiling. What I did not realise though was that the MVHR ducting has to be in an insulated space. So now we need to insulate the MCHR which loses almost the entire saving. The installers have recommended using 50mm foil backed insulation wrapped around the ducts. This is fine, but I wondered if in areas where the ducts are installed just above the roof trusses and the loft insulation was pushed under the duct work could be just add another layer of rockwool that covers the duct work? This would be a lot faster and cheaper, but there is more risk that bits of the duct aren't covered.
  25. Having recently replaced the filters in my MVHR unit, I'm pondering whether it would be worth fitted additional filters in the actual ductwork to do the majority of the filtration. Something like this: With an additional filter (lets assume its a fairly coarse one) there would be some pressure drop if I were to do this, which I could compensate for by increasing the fan speed. Any other thoughts?