Rishard

@Bitpipe- I thing gas is still low initial and running cost. It’s a big investment in ashp/pv ect. I’ve attached a site plan also to show some of the other buildings nearby which will add to some of our shading. I’d be interested to see this all in a 3d model to see where the sun hits throughout the year. I think leaving provision for electric and plumbing connections for ashp would be wise. I guess it isn’t possible to cool the ufh I summer with a gas boiler set up? @joe90- is your conservatory part of the main building/airtightness envelope?

@Bitpipe- thanks for linking jack and likewise, thanks jack for the links. Like I mentioned, I had planned for a gas boiler based on its lower cost. Cost plays a big part in this. I feel either a cheap ashp could work or a regular gas boiler with ufh. Or at least the provision for one or the other. Maybe if I don’t go down the ufh route then having a cooling system would be wise. @Iceverge- I love the low tech approach. Does this provide heat into all rooms such as bathrooms. I know people are tending to have a towel radiator in the bathroom as a heating source. With our project I worked with a local architect who I have a good working history with. Although he is not a passive designer, he was very willing to learn and take advice. We had a few sessions with bill from the green building store which helped a bit towards our thinking and some design aspects. The house faces south towards a conservation area which limited our design a little. The north faces the garden, the best aspect. We have no west glazing and very little to the east. The plot dictated our location a little and it will be shaded a little by neighbouring buildings during the winter. We compromised a little of form factor vs style I guess. We made it through planning and feel happy with the look. Some of the internal walls/spaces may change a bit but we labelled up plant room/airing cupboard ect to dedicate at least some space in the house. We are happy to make some changes to these once I have a good grasp on how much ‘plant’ we will be looking at.

@Bitpipe- I hear your points on over heating and has probably confirmed my inclinations regarding running phpp. Our house is likely to be shaded by surrounding properties during lower winter sun and we don’t have huge areas of south glazing. We do face south so would feel more comfortable having had the solar effect on the house looked at. It’s very easy to forget over heating in midwinter living in a draughty house! I like the ufh cooling method too using the heat pump. It certainly adds more interest knowing it can be used as a cooling tool. What runs your ufh? Can you use it to cool the slab? Is an aircon split something which can work with the mvhr or a separate system? @Iceverge- I’d not heard of a thermal store. I also like the sound advice on ufh and an uvc teamed with ashp I guess the next bit is pv to help it all along. Do you run your system on e7? Or do you have help from solar along the way and batteries ect. I guess once you have a electric system to sensible thing is to invest in pv. I’ll have to price up all of the components to see what overall costs would look like. I originally planned the same system but with a gas boiler in mind years before I got to planning. That was based on the price of both a gas boiler and cheaper gas. I hear your point on gas boilers delivering high heat quick which seems unnecessary in PH. Prices are also heading north so initial spend may soon be paying back quicker. Are people getting much from their pv over winter?

Excellent. Is the large thermal store you mention something different to an uvc? Am I right in thinking this is just for dhw and not the ufh? There are a few options floating by around in peoples experiences. It does seem that a small ashp would still be suitable to cover both ufh + dhw. Is this your thoughts? I feel a diy pv system would also benefit this style of set up. I’m mainly seeking advice on the type of system which would best suit the build. I guess overall capital investment has a part in this and also simplicity.

@Iceverge- our ground floor is 147m2 and is planned as a passive house quality build. My friends barn however is not. Built to building regs and is yet fully functional so he won’t have any idea till he starts trying to heat it to work out his usage. I guess the above calculations wouldn’t apply as you state. I’ve been reading a lot on here regarding active slab heating options which I feel could be a good way to go. Having young children I guess that my heating will fluctuate a lot more than others. Likewise with DHW. I’m happy to seek input on this. I like the idea of the low capital cost of the Willis heater for a slab if I can arrange a solution for dhw. Again growing children may influence this decision. Is the fan heater your main CH currently? Do you have any other system in place? An ‘ease of use’ system would be preferable like you say without over complicating things. Coming from a joiner talking plumbing ?

Having done this on my build now it looks like a 2kw heat source would work. I’d be happy to amp it up if required. This was fairly surprising as I calculated my form factor at 4. I did put in 300mm in the floor walls and roof mind. Out of interest I did the same calculations for a barn conversion I did which is under 1/2 the size. The form factor came out at 4.6 and is 80% new build work with only 100mm cavities. The 30m2 of wall which is uninsulated I adjusted the u-values. The heating requirement was similar to my project. Does this sound right? I guess in the barn conversion it wouldn’t consider the thermal bridging issues and air leakage? This conversion was before my understanding of airtight/bridge free design. I know the windows and doors wont be to the high level install spec they could be with tapes ect. What would you say all of these factors would contribute to that overall heating requirement? How long is a piece of string I guess?

How is the learning going? Have you decided on the way in which you plan to insulate the building? Opting for the more sustainable materials generally means you need more of it to achieve the same u values. It also tends to be more on the expensive side. I took a short course on radical retro-fit which focused on exactly this. There are a few options. External insulation and render or internal insulation. Both have different pros and cons. Often the deciding factor is what is allowed in your area. Once one of these options is decided then you can narrow down your insulation material options. I work on a lot of conservation projects which require breathable materials, these also fall under the ‘sustainable/green’ category by default. is your building cavity wall?

@Thorfun- I agree, nothing more re-assuring then personal quality testing! Who did you have in your top 5 list? I once visited a lovely conversion with 3g windows by George Barnsdale who have been making windows since 1884. Very efficient and well engineered.

Would be interesting to see peoples comfort reviews from these homes. The houses sound like they would be fairly easy to heat anyway.

@SimonDCheers, it’s good to hear someone’s lived experience. I guess in a study where your sat doing nothing all day they would work well. I remember visiting a building show and experienced the warmth when near them. I was just uncertain how that would translate to a living space. My fear is he will struggle with these in his main living space where his ceilings are double height/vaulted with a bedroom mezzanine.

What build quality are we talking? Similar section sizes and wood engineering do you know? I’ve seen whole house window quotes locally from small (ish) joinery manufactures with 10k difference on price yet very similar product. This job was mainly accoya double glazed units with identical spec.

Are the velfac windows a good spec?

I can now see this has been widely discussed. A friend was interested in using them in his relatively small barn conversion. It had a footprint of around 45m2 with some insulated walls and some un-insulated. A bit like a small church I guess. He doesn’t have gas on site. It sounds like these don’t really warm a space particularly well? Just the occasional person? Is it fair to say the objects they do heat don’t stay warm once the panels are turned off? Like the insulated concrete slab/ masonry walls ect?

Has anyone any experience with infrared heating panels? Either using them or opinions on their effectiveness.

@gravelrash- Certainly is worth the few hours labour for that kind of saving. The same applies to the whole build, the more you can do the more you can save. When I go to the http://orlimex.co.uk/ website it comes up with international plywood supplies. Is this the same company? Cheers

@gravelrash-Still a worth while endeavour by the sounds of it. I’ll not rule it out yet!

@gravelrash-Where did you buy your basalt ties? Ta

500 year payback! That’s that decided then. It’s sounding more and more likely to run phpp. If not just for piece of mind. I was planning mineral wool in the cavities. Is eps better for resisting moisture? Did you use a raft or trench foundations?

@Chanmenie-Would love to hear how your quotes compare from nordvest and norrsken.

@joe90- I like the sound of that approach. After working building all day, coming home to then calculate everything starts to hurt my head. Hense why I was look to pay to have phpp done for me so I can focus on what I do best. Did you follow any of the above calculations for your heating system and mvhr system? These 2 things are the subjects I know least about.

@Iceverge- Cheers for that calculation. I’ll certainly give that a try. Seems a bit more my level of workings out. Like you, I have a designer offering the phpp service for around the £900 mark. What cavity ties did you end up using. I know these contribute towards a thermal bridge so would be curious to know how bridge free I need to be. The cost difference is fairly high by comparison and I’m wondering what other people have used.

Do you know if there are any instructions for filling this out and interpreting them? cheers

@Gus Potter- my gut feeling is to try have it modelled. The main reason being this is my first low energy build. Although I’m confident with the detailing and build-ability of the project I have little understanding what this may look like in terms of its efficiency. Knowing some of the figures would help inform how best is can heat the building. Likewise, I’m not trying to scrimp on having a sensible heating system that can deliver heat when it’s needed. I have small children who will one day be those teenagers you talk of! I have a readily available supply of wood offcuts from my work so did think of a small log burner. I know this may be seen counterintuitive but just a thought. I’ll await other peoples views on this…. We have no west facing glazing due to neighbouring boundaries to west and east. Glazing to both north(garden) and south.

I’ve not heard of these programmes. I had hoped to outsource this part of the work to someone more capable than myself to avoid error. It was very much my plan, only slightly scuppered by their availability which made me look into alternatives. I’ll look in to TAS.

Great, I’ve read about people using this spreadsheet. Is it fairly manageable for a builder? Construction will be. Block, full full cavity, block. There will be a brick plinth detail and a combination of render and cladding. On plan we have 300mm dritherm cavities following the Denny dale approach. Metal web joists, glue lam ridge beams with potentially warm roof vaulted ceilings. Plywood window reveal boxes and triple glazed windows. Dense block for walls with a course of thermal block work at concrete slab and above a steel to carry part of the 1st floor.