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Hi, just joined because I was reading all the posts about MHRV. I have the basic design of my proposed 110 sq M house: 3br, 2 disability bathrooms, superinsulated, Off centre roof pitch with the long side facing N (S hemisphere!). wrt the MVHR, it seems the most economical solution for me is a Mitsubishi Lossnay ceiling mounted. After doing some research, I have found a Chinese Co that supplies 90mm round Semiflex duct & accessories. Yet to create a manifest, but providing the freight is reasonable, should be economical. The Co is: https://www.erviguicoo.com/fresh-air-abs-distributor-with-high-quality-abs-materials-product/. So far I have a catalogue, but will need drawings, etc. The Lossnay will be locally sourced for warranty. btw, the Steib-Eltron tool is great for designing the MVHR system. Some details of the build: light construction because there are no snow loads! The Wall frames will be Pine, with the top & bottom plates screwed as well as nailed (due to Cyclone uplift). Studs 90x45, on 600 centres. The roof trusses will be at 900 centres. The roofing is Trimdek corrugated iron, but I will use 0.48mm as I will use S5 mounts for the solar PV that are rail-less (just screw to the ridges, hence the thicker steel). Hempcrete: 270mm thick walls with 10mm lime based render each side. One thing I will do differently is to raise the truss bearing point so I can have 300mm of insulation across the ceiling with no step down, The Hempcrete walls will go to the top of the outside edge of the trusses, & will return into the ceiling, sitting on a ledger. Then I can seal & attach my OSB airtight layer directly under the trusses. The OSB also gives wind bracing. (all joints sealed & taped). 300mm Fibreglass insulation above OSB. This will be built on a slab foundation, using Cupolex domes. The edge rebate will have stainless ant barrier/dampcourse. Air sealing: all transitions taped after walls are rendered. Slab is to be polished, so the concrete will be edge primed before taping . Blower Door test: I will DIY a blower door using a s/h Automotive 12v radiator fan. I already own a digital manometer, & after reading the MVHR threads will buy a Testo 425 Digital Hot Wire Anemometer (the computer connected one), & control the fan with a DC speed control to vary output. The Air volume can be easily measured with a cone over the fan, & something like a piece of 150mm plastic stormwater pipe, with a hole to insert the Anemometer probe. This anemometer is apparently sensitive enough to check for leaks around windows, etc. The Automotive fan will easily blow/suck 50 pascals. My build is also in a bushfire zone. No gaps bigger than 2mm in the outer sheath & roofing: I do not use Soffits or barges: I use a product called G&G gutter brackets that screw to the metal roofing overlap. I use 150mm half round gutter that I can easily clean (with a moon section on a pole). The gutter ends are sloped so I can sweep the leaves out. In Australia, the roof space must be ventilated, which is accomplished with about 75mm wide folded perforated aluminium sheet that runs on top of the hempcrete, to the underside of the roofing. I have designed a system that stops the embers. The vent at the ridge is a product called Vent-a-Ridge. This allows air to pass under the (raised) ridgecap, exiting through the corrugations. There will be the usual smart membrane & counter battens for air flow. Hopefully I can build this for less than a ´normal´ builders build (aiming for $au2500 per M sq) regards, Doug

We learnt how to keep our house cool this summer and thought we'd share what we've learnt in case its of use to others. We're in a timber frame building built to the Passivhaus standard but not certified. We don't have an ASHP, so no slab cooling for us but without a doubt our (not so secret) weapon are the external blinds. All our east and south facing windows (with the exception of 3 east facing windows - more on them later) have external blinds and as predicted by the PHPP these are the game changer. Our secret weapon is the little personal weather station (PWS) in the garden and with it's help this is how we've kept the house cool: In the evening when the outside temperature according to the PWS is below our target internal temperature of 21 degrees all doors and windows are opened and the MVHR ramped up. Overnight all the inward tilting windows are left open with the MVHR staying at a higher level and it stays like this until the PWS shows that the external temperature is rising towards our target 21 degrees - that happened at 07:50 this morning. As soon as the exterior temperature reaches our target then all doors and windows are closed and the MVHR is reduced to its lowest setting, we monitor the air quality with a couple of CO2 monitors as recommended by @Adrian Walker and increase the MVHR speed as required to keep good air quality. All sun facing windows have the blinds down, we have the mesh style blinds that don't block off the light but stop lots of UV. With this technique our hallway temperature has peaked in the early evening at around 21-22 degrees and the kitchen/dining room which has lots of east and south facing glazing has stayed below 24 degrees. As soon as we open up we get rid of most of that unwanted heat. The hallway starts in the mornings around 19-20 degrees. The reason I think the PWS is a secret weapon is as far as I'm concerned you need to accurately know the exterior temperature and when to let it in and when to keep it out. On a windy day, 26 degrees can feel cooler than 21 degrees but if you let that stuff in the house you're gonna regret it. If you don't have a PWS you'll probably be able to find one situated close to you on the Weather Underground website. Oh, and the 3 problem east facing windows without external blinds: 1 is the utility room. That has an internal blind and as it's the utility room the internal door to the rest of the house is kept closed. That room gets warm 25-27 degrees but the heat stays in that room which of course has an MVHR extract so the heat is slowly being pumped out of the house until it's door/window opening time then we throw the heat away with vigour. 2 is the ensuite which we deal with in exactly the same way as the utility. 3 is the main bedroom which has a great big window and curtains. The curtains remain closed while the sun is coming in that window but the doors are open so as that room warms up its heat is not being contained in that room. As the sun moves round and that window is no longer in direct sun the curtains are opened and a big old chunk of hot air falls out to be slowly extracted until window opening time. To me, its like the house taking a long overnight gulp of cold air and then holds its breath throughout the day until the temperature is 'just right' again.

Re-building a 1970's split roof style house situated in a 1/4 acre plot beside Belfast lough. The project is designed to be as close to passifhaus standards as possible and to be completed end of September 2024. Innovations are the use of Cork insulation sourced directly from Portugal and the use of a Nulok roofing system for my PV. \the house is situated only 50 feet from the sea and is upside down living with the bedrooms downstairs and living area upstairs with a large cantilevered balcony and huge triple glassed window area to capture the views and changes that we get to the natural light here in Northern Ireland. The house itself once finished will look something similar to a classic HuffHaus, but purely by coincidence. I would be very interested in hearing from anyone who has fitted a NuLok system as I've had a few issues getting info out of the supplier.

Hi all, about to embark on self-build project. We have plot and planning. The layout optimises solar gain so I am keen to achieve passive house standard. I have noticed on this forum that many self-builders seem to include UFH in their passive house build but I have been told this is simply not necessary... So i'd be grateful for thoughts on this please!

We bought the bungalow in 2018 to move my elderly parents closer to us following Mum's stroke. While she recovered, they needed help most days, i was spending a lot of time travelling back and forward so it made sense to move them closer. As they lived in Windsor, we could not afford to move that way and I was very suprised when they agreed to our suggestion to move closesr to us. But it has proved very valuable in the years since. I think we were very lucky in that when we started looking, this property was up for sale. Its a 15 min drive for me but not too close. The layout was workable and it came with a garage, workshop and a large garden, mostly on the outside, wrapping round the corner plot. And it was perfect fo a Motorhome, which we'd be wanting for years but had nowhere to keep it. 😃 Our first change was to add a shower room as they both struggle to get in and out of a bath. We had a good builder, Patrick, who we had used on our previous renovation (Scooby Cottage) though we did have to wait nearly a year before he could start work. Having the shower room made a big difference to them and as we had applied for planning permission, we had a free shot at another for 6 months. So i drew up plans for an extension to the kitchen, as it is not very large with only a small amount of worktop. After receiving pp, we decided that the parents would not cope with the disruption so left it. But now we are looking to the future and what we can do. In the long term, when parents no longer need it, we want to extend the kitchen and across the back, to give a larger open plan space, and move in ourselves. Selling our current house to pay for the renovation. We dont need a lot of space and the bedrooms are fine, we'd use one and convert the other into a dressing/storage room. But after wanting to build a Passivhaus for years, and hearing about the benefits of living in such from many on here, I am hoping we can renovate to a good enough standard to give us a warm, low energy, home without any draughts. So thats the plan! I hope you'll enjoy the 'journey' as we progress through the renovation. Next time - Using an Architect firm. 🤔

Hello all, I'm a chemical engineer working in the sustainable energy industry (who right now wishes he was a structural/civil engineer) and I'm just over one year into an EnerPHit retrofit of a three bed end terrace. I'm passionate about sustainable housing and sustainable urban design. Currently in the middle of levelling a concrete ground floor and working out how to reinforce a timber first floor of a house that has been stripped virtually back to brick. This is my first time joining a forum of any kind and I look forward to hearing advice from the community! 😃

Hello buildhub residents. My first post here. I'm self-building a passive house in East Anglia and I'm looking at heating, DWH and potentially cooling solutions. My question is this - a load of companies seem to manufacture units that are either multi-split of mini VRF and have A2A refrigerant inverters available with a hydrobox for DWH (that's my reading of the marketing docs, please correct me if I've misunderstood the technology) But NONE OF THEM are available in the UK it seems (I hope I'm wrong, but I've called them and nobody knows anything about these units here). Does anyone have a good sense of why they're ether not bothering with the UK market, or why they're unable to get them licensed here? Maybe something to do with the distortions created by the Boiler Upgrade Scheme? The list has most of the big guys one it: Mitsubishi PXZ series - see around page 25 of this pdf here: https://kokotasgroup.gr/entypa/pdf/FULL_PRODUCT_HEATING_WEB--281-29_6166.pdf Samsung EHS TDM Plus Climatehub - https://samsung-climatesolutions.com/en-gb/b2c/our-solutions/home/heat-pump-solutions/heating-cooling/tdm-plus.html Daikin Multi Plus - https://www.daikin.ie/en_gb/product-group/air-to-air-heat-pumps/multiplus.html Panasonic Aquarea Ecoflex - https://www.aircon.panasonic.eu/IE_en/happening/aquarea-ecoflex/ LG Multi-V compact with Hydro kit - probably too big for my house, but anyway https://images.b2bmkt.lge.com/Web/LGElectronics/%7Bc5c4ca24-a96c-4aed-9cc9-97e1f6dbabf2%7D_2023_4Q_White_paper_Hydro_Kit_Low.pdf? ArgoClima iseries split - https://www.keaneenvironmental.ie/argoclima/iseries-split-pump/ Midea CirQHP- https://www.prnewswire.com/news-releases/midea-comes-to-ish-frankfurt-2023-with-its-latest-water-and-space-heating-solutions-301774592.html And yet - nothing available in the UK....

Hello, I am in the very early stages of designing and building a passive house, based on the closed panel prefabrication method as used by construction companies such as PYC. I've been thinking about how the house is to be furnished internally and the implications of attaching heavy furnishings to the internal faces of exterior super insulated walls, either for stability in the case of fitted wardrobes etc or the suspension of wall cabinets and even TVs. These walls, I understand have internal airtight, vapour-check boards inside of the insulation which are then battened to provide a service void of around 40+mm prior to plaster board. It is, I'm told, imperative, not to pierce that vapour board surface membrane to maintain its moisture and airtight integrity. I would be very grateful for any observations from those with experience of self build of similar properties or builders who construct them / fit them out in on a regular basis to help understand what options are available and what would be the best course of action as the project progresses.

Hi all, We are planning a new-build that will approach passivhaus standards, and I feel that going for the typical ASHP+cylinder+UFH is engineering and financial overkill, especially since we like to have the house around 18-19C and cooler at night. Instead I would like to have minimal electric radiators (or even just electric blankets) and something like the Mixergy iHP* to provide hot water at COP > 1. I would like to set it up so that it has two inlet/outlet paths according to external weather: If solar gain > heat loss: extract from top of vaulted glazed area and return to bottom to provide cooling If solar gain < heat loss: extract and return from/to external environment The second case is to avoid having to run the radiators to provide hot water on days with no sun, which tend to be wet and not sub-zero where we are building. Does this sound feasible? We will be getting an MVHR, but I was hoping that by having only internal/internal or external/external config we would avoid interfering with it's operation. Are there any products out there that would allow a compact solution for changing the flow path? It doesn't have to be automatic or anything, but I want to avoid a mess of flexible tubing. Cheers, Diarmid * other products are available, I just like the look of the warranty and modularity of this one.

I've used an architect to design the gaff, and a planning consultant to apply for planning. If the application is successful, I'm likely to go with a MBC type of build. The next decision seems to be whether I use the architect to hold my hand to progress the project, or try to go it alone. I think an MBC type route will mean I don't need separate construction drawings and structural engineer input for the shell or foundations, but I'll need other information for building control - layout/spec details for rainwater drainage, sewage pipes (no mains sewage, so treatment unit), MVHR, electricity, plumbing, mains water and more stuff I haven't thought about. I'm sure the architect will do/arrange this for me, but at a likely hefty cost. I'm thinking I will also need to have construction details for the roofers (zinc standing seam), cladding (horizontal wood), guttering (there's a valley to contend with) and other stuff I haven't yet thought about. I think it's important to ensure that these external items (plus windows and doors) interface in the best possible mechanical, but also aesthetically pleasing way and I don't want to leave it to each trade to decide on the hoof. I'll also need I'm retired so have the time, but don't know if I can achieve the comprehensive level of detail that will mitigate as many 'on site' problems as possible. I'm a detail person by profession, and am not comfortable leaving things to chance. Although I appreciate that there will be unforeseen issues that have to be navigated, I'd like to have as few avoidable ones as possible for the sake of my wallet and sanity. My initial thinking was to have a phased approach to the project, but am aware that a holistic view is also necessary to avoid the 'if I'd only done that when I was laying the foundations' feeling when a guttering issue pops up 6 months later. Having someone involved who has experience could be very helpful in avoiding expensive mistakes. Am I being overly pessi/optimistic?

Hello, I was wondering whether anyone could offer any thoughts or advice about the following threshold detail. I'm actually an architect myself and am working solo, so I don't get the benefit of second opinions. I've always worked on larger schemes at the earlier 'conceptual' stage of projects so my practical knowledge of construction details is a little rusty now. This spring, I'm piloting a digitally-enabled kit-of-parts construction system assembled from cnc-cut plywood or OSB that I've been in the process of developing over the last year. Its just a small garden room, so I'm not too concerned about U-values, but I am trying to achieve airtightness to test out how all the details work before I self build our family home next year. I'll then have it tested to see how airtight it is. So, on to the detail - see image attached. Here's the floor build up from top to bottom: 50mm brick pavers, 10mm mortar bed, 18mm T&G Wisa Ply floated floor, 60mm Rigid insulation, RC slab. I'm thinking I can just secure the concrete threshold piece into a bed of mortar over the floated ply substrate - just like the brick. The DPM coming up the slab edge can fold over and tuck under the threshold piece protecting the exposed edges of ply and insulation. An additional waterproof board will go over the DMP too. The only reason I'm questioning it is because I haven't found many examples of how it is done online and so am relying purely on my knowledge/research and common sense. Anyway, any thoughts greatly appreciated. Thanks

I am working with a structural engineer specialising in Traditional Timber frames to design a new build Wealden Hall House. Could anyone point me towards a person / company with a good degree of experience in efficient building design for traditional timber frames? Pursuing a truly historically-accurate frame design results in some specific cold-bridging issues (use of continuous timber posts / plates / joists through cross sections), that we are seeking mitigation strategies for. Thank you.

Hi all, Just to introduce myself. We are just about to finalise our renovation/extension project in the West End of Glasgow. Detached bungalow which we have pushed out the back 6m and also added another storey to it. The last two years, to be quite frank, have been pretty hellish, not only in terms of financial outlay (budgets - lol, aye ok) but, personal energy investment. I don't think we really realised how big an undertaking it was until one day, standing with my brother in law and we had no roof and it was just basically a shell. My brother in law looked around and went "fk me" and then it kind of hit me, square in the face or what we have taken on! We would have been quicker and cheaper, flattening the house and doing a fresh build but we weren't allowed to do that (a story for another day). Anyway, external wall insulation has just been completed and we are about to to start the roughcasting externally. Because we look at the building everyday we don't kind of realise how impressive it is and its totally out of context with the neighbours single storey 85m2 detached bungalows(we have 18 objection letters from the neighbours and even neighbours as far as 1.5 miles away, councillors, mp's the lot) as ours rises 6.2m at the back (the neighbour calls the wall facing him The Berlin Wall!). I work in the insulation industry but to be honest, I have learned so much more about insulation, insulation u values, lambda values - the works. We have made mistakes yes but fixed them. At the end of the day, we have built a house in which we are only temporary custodians but this house will stand proudly (Berlin Wall-esque) for a long long time and with excellent insulation and air tightness values, solar panel power generation and we are really proud of what we have achieved. Incidentally - never again!

Hi, I am in the middle of building a timber-frame house (awaiting first fix electrics and plumbing). The recent hot spell has convinced me to get brise-soliel on the south facing upstairs windows. I have them planned for downstairs already. But I played around with PHPP and although my overheating reduced it didn't disappear. My phpp consultant has no figures inputted for L31 window ventilation air change rate and P59 Window night ventilation (in summer vent sheet) Has anyone got 'typical' figures for these? I have used 0.35 and 0.15 respectively and my overheating drops down to 3.9% (with all southern windows shaded). Apart from fitted brise-soliel there isn't much else I can do as all doors windows are fitted and insulation is in place - so I just want to check if the ventilation figures are reasonable. Thanks

Hi everyone We bought a plot with planning permission for 2 houses here in Aberdeenshire last December. During the period of reflection afforded to us by coronavirus we’ve decided that we’d rather not build the design that we have planning permission for but instead construct more modest dwellings to Passivhaus standard. Would be very interested to hear from anyone else in Scotland and especially in Aberdeenshire regarding their experience of constructing a Passivhaus and any associated planning or building control challenges? Live long and prosper!?

Hi all, We have just started to build a two-story timber frame in Donegal in the North west of Ireland. We are building to passivhaus standards and have an experienced passivhaus builder. I have gained loads of information from this forum and hope to get some more as the build progresses. We have a lot of south facing glazing (by design - to capture views of Donegal bay) and have added some shading to the ground floor southern windows. PHPP calculations demonstrated that overheating can be mitigated by adding some cooling from the underfloor slabs. We intend to use a Mitsubishi 8.5kW ecodan and have a Brink passive certified MHRV specified. Phpp and plans attached. Two storey-Floor Plans, Sections, Elevations 280620.pdf

Hi folks. Thanks for letting me join this forum, we're looking forward to sharing information and learning lots! We're just starting out on a replacement dwelling for the bungalow my father built in the 1950s. It'll be our 2nd self build... Or rather self managed build - with some physical input from us all. Our 1st was 25 years ago. This one is to be approaching passivehaus probably and maybe a timber frame build. We also have yet to gain planning and we are fortunate to have a stunning location. We're a very practical 60something couple with a 30 something married son +DIL who we will be sharing it all with. We're planning to build a house which provides 2 separate living areas and kitchens, but shares a utility room and plant room, so it can ultimately be one house when we've popped our clogs! Looking forward to the journey!

Hi, new to the group. We are planning a near Passivhaus bungalow, commencing in Jan

Hello everyone, first post and just wanted to introduce myself as you all seem like an extremely informative and helpful bunch - I hope one day to provide the same level of contribution and advice when we finally get to build our dream! We are hoping to build a 4 bed Passivhaus in North Somerset, about 8 miles south of Bristol. We are still in the very early stages of planning, as in, not sure if the plot in question has any potential for planning as yet, so have been spending a considerable amount of time reading about the Local Plans, NPFF and what the implications are of trying to build a village washed over with the Green Belt and is outside of a settlement boundary. The plot is part of a large garden, so might be considered a windfall plot but the two issues I mentioned are obviously very difficult to overcome, if at all. We do not have the sort of budget for a Paragraph 79 house but nevertheless given the location, we felt it was an avenue worth exploring further. In any case the research we have been undertaking generally won't be a wasted effort, since I feel it is helping us understand the build process and makes us better informed clients. In terms of build systems we are very keen on ICF, and going through the process now of trying to understand what the pros and cons are of the various systems - of which this site has proven very helpful already! We have also started to try and make a short list of architects that meet the following criteria: have demonstrable Passivhaus experience, have ICF experience, and can provide a Passivhaus design beyond just a box (yes I know that it is the most efficient design in terms of energy efficiency, but hey, its our dream :). this has proven difficult to say the least, the vast majority of architects who are local who have Passivhaus experience seem to only have experience with timber frame or seem so fanatical about the concept of eco design that I wondered whether we would be chased away with pitch forks if we even broached the idea of a monolothic concrete house. :). The other type of architects we found with lots of Passivhaus experience seem to be based in London, and frankly I wonder whether they would be so fancy that our fairly modest budget just wouldn't be of interest to them. If anyone can recommend an architect who meets the above criteria that would be great. So anyway, that's a brief synopsis of where we are, I sincerely hope to be able to contribute further to this site with updates!

Hi everyone, Just a quick note to say hello and introduce our project, which is a self build at the Gravenhill site in Bicester. We have submitted for planning and intend to construct using SIPs to a near Passive Haus standard. While we have refurbished a couple of Victorian houses, a self build is a significant step up. Thankfully I have stumbled across this site and it seems it will prove invaluable to what is likely to be a steep learning curve. I look forward to discussing the project and contributing once I have some knowledge! If anyone is interested I have uploaded the 3D drawings. Thanks, Tom 370 - PL 500 Proposed Renders.pdf

We are trying to do our best to create a pretty airtight house.... Our Architect has suggested a joiner made front door. Will this be a huge source of air leakage? We are installing MVHR and ASHP and it will kill performance if the door lets wind through. Our current double glazed french patio doors let a gale blow through on windy days....

We are self-building/managing an MBC Passivhaus near Norwich, just starting plaster-boarding. We are aiming for Passivhaus Certification. Our first MBC air-test was okay, 0.47ach, despite (and it seems others of you have a despite) there being a couple of areas where air-tightness could have been better. Having remedied these areas, and been diligent about sealing penetrations, I'd anticipated an improved result, however our recent second air-test wasn't to the required Passivhaus standard of 0.6ach. We checked what we could with a smoke pen, but couldn't find anything significant. Has anyone had similar circumstances, and did they manage to discover why? I'm applying additional taping to window reveal corners, in the hope that this is enough. thanks in anticipation.

We've just completed a new build "house for life" - it started as "Passivhaus Principles" as we didn't want to commit to certification during the planning process because of its challenging form, but our Passivhaus consultants (Peter Warm) felt that with a few tweaks it could make it and, as of this week, it has been certified. We also had to go through the "Paragraph 55" (now 79) route to get planning permission, where you have to go to a Design Review Panel of professionals who get to decide if your design is "exceptional architecture". They unanimously approved it while Planning rejected it and also said they didn't want any further discussion on it. However, our forward thinking local councillor took it to the development committee where Planning was over-ruled (a story in itself). To be honest we are not hands-on self-builders in that we used architects, builders, etc to do it and it was an expensive build, but we were in a position to do this because what we actually hands-on self-built was a successful software company that was then sold. We were very involved in the whole process, living 250 metres from site, and especially in selecting and pushing the eco kit and we also had a planning condition to put a photographic record of the build in the public domain, which being a keen photographer I have done: www.thewalledgardendevon.uk Eileen designed the landscape and is now implementing it with muscle from local ex-marines. So it's a certified Passivhaus with private water supply, a positive energy house through solar and using both electrical and thermal batteries, with an EER of 101. We started a bit late on Buildhub as we were having problems with our Sunamp thermal batteries and we got a lot of help from @JSHarris in particular and others. However, happy to answer questions about our experiences if that's useful.....

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

The Passivhaus Trust has announced that the number of certified Passivhaus units in the UK has topped 1000 - with at least as many again in the pipeline. http://www.passivhaustrust.org.uk/news/detail/?nId=787