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I didn't put in any central heating in our passive house. None. These are the reasons. 1. Believed the evangelical true believers that seems to think energy is like magic. 2. Stubbornness driven by a desire to outsmart everyone else. 3. Complete confusion with the range of options. 4. The outrageous prices charges for ASHPs by plumbers who can't count their own fingers. 5. Option to fit an A2A was always there. We use a single resistance heater now . It works fine the rooms are all comfortable but it's dear to run. About €700/year I think. I put extra infrared heaters in the bathroom for comfort. I had expected it to be cheaper but we can't bank enough heat overnight on a TOU tariff. Also electricity is after triplling in price since 2019. Time over again I would ..... Fit UFH with a willis heater and the option of an ASHP like @TerryE with electric UFH in bathrooms too. Or install an A2A from the start with electric UFH in the bathrooms.

Careful or you’ll have the net zero stasi after you!! Think what this shows more than anything is the heat source isn’t really that important from a cost point of view certainly. What is extremely important is insulation and air tightness.

I was assuming Passivhaus

To be fair, adding the cost of PVs and batteries to the ASHP would make it expensive to have installed though, even with the £7500 grant.

I think the short answer is you need two more quotes - preferably from people who are not fazed by the job and want the business.

I'd advocate this approach but just with a cheap willis heater to start. Give it 3 years and the house will really have settled down and you'll have good data to make an informed decision.

Have you looked at knock down and re-building in sections so you live in the remainder and move over to the first bit of build as it is finished and in the end you have rebuilt it? Would take some organising but might be made to work out.

We were told by three different sap assessors that the sap would be so loaded that it would be unlikely that we would get planning So we gave up on an oil boiler

There are good advantages As the air enters the house it is slightly cooler than the house air, the warm air, pre heats the air so it cannot be felt. My living room terminals are at about 4m high.

We are going through our finances and have a problem 'timing gap' between builders likely last payment & mortgage coming through. We are borrowing money through family to cover the last couple of months of build, before we take out a normal mortgage & repay them all.....all to avoid a self build, high interest, mortgage. However, there is a risk of builder needing final repayment before the mortgage clears which give sus the extra funds to pay this cost & repay everyone. At what point of our 'self build' would we be able to start the mortgage rolling. Is it feasible to get a standard mortgage pulled together during the last month or two of build...giving us time to receive the money & pay builder within 2 weeks? ie...Does a mortgage need the kitchen & a single working bathroom before we can start the ball rolling, or does the mortgage need any other triggers to allow us to start the process? Emailed our mortgage advisor, but she will take a few days to reply to me...just want to see if I can get any comfort beforehand. Thanks very much

Our vaulted bedrooms have the vents on the walls, while the vaulted living room/dining room/kitchen have them on the ceiling. Can't say we've noticed any difference. The issue with the ones in the living space was more to do with ensuring the battens for the ceiling were deep enough to take the pipes and the vents. Simon

We had vaulted ceilings upstairs and had the bedroom supply vents in the wall around 600mm above the floor. The bathroom and ensuite extracts were in the wall near the ceiling.

I wouldn't worry about it. Does it really matter if the air right up at the ceiling isn't quite as fresh as it as at head height?

Interesting, so actually designed for ‘senior care’ and building management.

To be fair there would still be very limited access to quality installers of heat pumps in NI. Oil would be widespread here with a multitude of options for installing and servicing. The price of oil is low now but it fluctuates yearly. Electricity prices have been fairly consistent until this past 2 years. Have you got proper as built heat/dhw demand calculation done yet?? You could always install oil now but with pipes/electric connections already installed so in the future if you wanted to install a heat pump it would be a much easier option.

Oil definitely cheaper to run and many are 97% efficient But no longer an option on a new build

The problem with this "whole roof" PV idea is you need to choose the panels at design time and know the size of them, and then design the roof to be an integer number of panels in each direction. And solar panels don't seem to be made to standard sizes. So you either want to order your panels as soon as you draw your plans based on that size, or hope and prey that the size you want is still available when you actually come to build it. Then because supply of that size of panels is not guaranteed into the future, you might want to buy some spares and store them away safely. The next obstacle is a bug bear of mine, we have a stupid system where anything over 3.6kW may not be allowed by your DNO or may only be allowed if you pay for upgrades. If we are going to have lots of PV on every roof, that limitation is the one big obstacle that needs removing.

Yes. Undo to small screw and it all slides out, mine also has the probe the ASHP sat snuggled in with them as @ProDave mentioned

In a passivhaus or anything remotely close, absolutely rubbish. Fan coils - flow temp 35. CoP at -2 around 3.5, CoP at 10 deg OAT 5. UFH flow temp 30 or below CoP at -2 around 3.7, CoP at 10 deg OAT 5.7. even if you did all DHW at peak rates, you still cheaper. You can heat off peak with UFH, I currently pay about 13p per kWh. There is almost no servicing to do, look and clean radiator if required. An hour tops. UVC you would do anyway. No more than a gas boiler, possibly less. How the heck are you going to control an oil boiler, and manage heat losses into houses? with virtually no load. You would have to install a thermal store, heat to 70/80 degs for DHW then let the temp down for heating - not in the spirit of Passivhaus.

Mmmm Yes oil is looking quite good at the mo. I've just updated the comparison chart for the next cap etc.

That is certainly a water thermostat. It is a bulb on the end of a capilliary tube that slides into a thermostat pocket in the cylinder. the grey plastic cover contains the actual thermostat and the fact it is slightly wonky is of no consequence. That looks quite low down for the normal thermostat position, I assume there is an alternative thermostat pocket nearer the mid height of the ctlinder? If you are heating it with an ASHP there is very often a temperature sensor supplied with the ASHP as well.

This reads like an AI passage.

To my way of thinking all suitable roofs should be built like this.

Hi! im in the process of buying my first house, and I’m planning to do a lot of DIY work on it - landscaping, flooring, kitchen work to make it our own.

You can get what I suspect is the chip from mouser - https://www.mouser.co.uk/new/texas-instruments/ti-mmwave-iwr6x-sensors/ Alternatively if you just want to watch one person SEEED studio do a 24GHz (and here, apropos another thread this morning, I think we use a capital G although I have forgotten why) is one I have been experimenting with! It works OK but fine tuning is proving interesting - its a pain adjusting settings while lying down to get it to detect a fall!

Yes I prefer the top one (it’s close to what I did) and you can use it for storage.

Ok I see where you're at. Not a simple junction re airtighness to do as drawn. My preferred way for this would be to take the airtighness layer up the inside of the wall, across the top of the wall to the outside plate and up the top of the rafters. Then insulate between and above the rafters. You'll need to screw on rafter tails on top of the rafters. This way you've no timbers breaching the airtighness layer which makes it far far easier to construct. I'll do a sketch in the next hour or two if I get a chance.

Did Princess Kate do any work on it?

+1, insulation just needs attention to detail.

I'd have thought you would have needed a structural connection between the joists and the rafters. Otherwise your rafters will end up like jean Claude van damms legs in that truck advert.

We’ve gone for three sets of sliders Nice easy to fit and much more airtight than bifolds The bifolds that I fitted on are previous build are pretty good But far from airtight I think it’s more in the design The manufacturer sent us larger seals Which seemed to help but made them hard to open and shut

I am a conservation architect specialising in listed and historic buildings; I run a small design practice in Altrincham but work across the UK; we undertake all sorts of design work (not just conservation-related). I am planning to build a contemporary house to (near) Passive house standards for my wife and I to retire into. This field interests me greatly but I am a learner and will hopefully be able to draw upon the experience of members and help others with my specialism and many years in practice. My grandfather, father, and now my youngest son are/were Architects. Thanks for allowing me to join.

That's the man. He will tell you straight if it can't be done, and other options.

When I did my build I was told by many here that my south facing 10m conservatory with bifolds into the house would overheat but frankly in the several years I was there it never got hotter than a good holiday in the south of France, (which many pay good money for) and during the shoulder seasons and even mild winter days was a lovely place to be.

Example conversation when BCO visited to sign off my pre plaster inspection (yes, I know yippee!): 'so you've got the egress windows for the guest annex, that's good...on boths sides, that's perfect. Oh, and you've installed a fire alarm in the area, that's good. Oh, and you've put in a fire door, that's a good idea, we didn't ask for that. You know you'll need intumescent strip and if the door is 30min, the wall will need to be 30 min also. Oh, plaster and skim, that's all fine then. Good job' I only accidently installed the door opening in the direction of escape...

Just to add to this with a bit of experience of what I would do differently "next time". I had installed 50mm twin wall duct for the electric supply. After completing the raft that duct was extended by the groundworkers to the electric kiosk with the meter some 20 odd metres away. Only later did I consider the cable needs - 3 phase 25mm. Upon picking it up from the suppliers I could immediately sense a problem coming. A) it was heavy and B) it didn't bend well. This week I discovered drawing it through a 50mm duct was not practical - should have used 80mm at least. Also the bends in the duct made pulling the cable through a nightmare. Luckily, after a struggle we got it outside the raft (all of 3 metres) but had to dig down to it and cut it open to get past the first (of several) too tight bends. Finally have strained back trying to pull it the last 5 metres - can't even bend over at present! Resourceful wife asked two random men in a family of four passing by to help and they very kindly stepped in and pulled it the last bit while I sat on the floor in a lot of pain. So, 1) work out cable needs in advance. 2) use a bigger duct than you think you need 3) consider running the cable through the duct laid out in a straight line, then placing both duct and cable in place in one go so you know it will bend where you need it to! 4) just get someone else younger and fitter to do it!

Your SAP calculations have a W/m2 and a W/structure per degree C values. Multiplying these by the HDD (Heating Degree Days) for your location or any other location will give you an idea of the annual energy cost.

I worked on a PH project last year (south of England) where the clients decided against any heating and it's been on an ongoing effort to retrofit it ever since. They also based the decision on talking to other people that live in Passivhauses and claim they only turn on the heating twice a year. Be very wary of those sort of claims: the people making them are often highly invested (financially and emotionally) to push the performance of their building. Also just because one PH building does not need active heating it means nothing for the next. ASHP is a bit of a red herring. The question is, do you need heating, and if so where and how much, and then ASHP is one possible solution to that. What is the max heating load and annual heating demand in your PHPP model? This is key. The project I mentioned before had a heating load of 3kW. This can be provided by a plugin 3kW heater - but then they baulked at having 3kW heater on 24/7 through the cold parts of winter (£25 per day). Mains gas or a heat pump are the options to reduce that cost.

But an ASHP will do DHW as well with a COP of 3 - 4.

Where they are not installed correctly for a passive house. Bollocks. Because people here have proved they work if designed properly 🤷‍♂️(I know mine did).

I guess it depends where you are. Up here in the Highlands no passive house will be comfortable in winter without any heating. My ASHP bills are not huge, and it is completely controlable including OFF

A few weeks delay for a lifetime of lower energy bills and emissions? Sounds like a deal to me. I can guarantee you you'll get no silly behaviour from Ecology, one of the best experiences with a financial institution for us.

Can the ridge beam be brought down so the rafters sit on top? Means no cold bridge at the ridge and a simpler fixing detail.

We built in 18months which I think is reasonably good for a self managed build. But the entire process from buying the site, to moving in, took 3.5 years. And we spent way, way more than anticipated. We've just had to take out another £30k loan to do the landscaping and a few finishes. Cash is king, sell up, ring fence your money and get started. If you have £300k, after you fees, design ,demolition, services etc, you will have £250k. Things will cost a lot more than you think, so you should have a build design that will cost £200k to build. That means a max of 150m2, 1.5 story house, with budget/ modest finishes.

We've just got a mortgage with Bank of Ireland, just needs architects sign off cert. A painful 3.69% tho 😭

Depending on what you are wanting to do, there is provision under an order made by a Scottish Minister by virtue of Schedule 1, Part 3 - holding of 5 acres of more, subsection 2 of the Caravan Sites and Control of Development Act 1960, that reduced the area of land required (from 5 down to 1) and crucially increased the amount of time caravans could be on land, (IIRC 5 or 6 months instead of 28 days) specifically for crofting land, the idea being to allow crofters an additional income stream. Unfortunately, the order isn't held online so you're reliant on the local planning office (or more likely the Planning Control Officer) having a dog eared copy to reference. I don't have a copy to hand but may be able to locate one next week.

Just remember that to be deemed 'portable' the prefabrication can only go as far as two separate pieces. So even something like a garden shed may not comply, because it cannot be moved intact without taking it apart. Caravans, park homes, shipping containers etc are all fine. Anything that arrives flat-packed isn't, unless the finished building is itself sturdy enough to stand being moved. But you dont' have to have it arrive in one big piece, you can build on site so long as you can show that the finished building is movable. I had no problems with planning, nobody lodged an objection. Small and restrained design is preferable to big and fancy. You can do everything online, although from memory I may have made a few phone calls too. I didn't actually meet anybody in person. I went through 'pre application advice' which at the time was free- I think they charge about £125 now. This gives you a non binding statement on the likelihood of your proposal being accepted. I then went for full planning, which requires drawings of the site, each elevation, and a floor plan. You also have to detail how you plan your road access. There is a standard to which you must adhere, with certain prescribed dimensions and radii. I think I waited about six weeks for a decision. You can also apply for planning in principle, but this is only really worth doing when you are selling a plot and want to leave the final design open for the buyer. One final point- not everybody is aware of the distinction between planning permission and building control. Planning is concerned with what something looks like and its intended usage (they will consider impact on local roads, schools, etc, so need to know likely number of occupants). They don't really care about details of how it's constructed. Building control, if applicable, will go in to the details of the structure and the regulations around disabled access, energy efficiency, etc. But they don't really speak to planning. So something can be exempt from one set of controls and not the other.

I was lambasted years ago on another forum for having a power shower but I take a lot less time in it than most people which does not seem to count. I would rather spend 3 minutes in a decent shower than 10 in a poor one.

In present house we fitted the hall and the landing with their own UFH zones. Total waste of time and pipe. There is so little external wall to lose heat, and so much internal wall to gain heat from other rooms, that these never turn on.