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Preach.

I'm actually not sure where the best place is to post this but as it's primarily about heat pump system design, I'll put it here. @marshian and @mads ,and maybe @MikeSharp01? you've expressed your interest so mentioning you here too. I hope the admins don't mind me putting this up here, but maybe if it is found to be useful, could be pinned to help so many of the people who come here struggling with poor heat loss calcs and designs and want to complete their own. I've finally deployed the tool I've been working on for initial public use. It's available free and open source, so repository on GitHub if anyone wants to host locally. It's currently in a bit of a test mode so I can get some feedback and bug reports to refine it and add further important functions. Just bear in mind I've been developing this myself along with everything else in life and it's been quite a major piece of work since last summer. It is now based on the CIBSE 2026 Domestic Heating Design Guide implementation of BS EN 12831:2017 and BS EN12831:2017 so complies with MCS design requirements. I have been using this tool for MCS heat pump projects in house that I'm doing. It's at https://openheatloss.com Important user notes: At the moment when you arrive, you can complete a whole project anonymously without logging in but this persists only for 48 hours or until you close the browser. The save a project, just register using name and email, nothing else. If you want to remain largely anonymous, you can just add the post code prefix to the installation address to set outdoor design temperature and Typical reference temperature. No need to put in loads of personal information. The workflow design is to work you way from left to right across the app tabs. Current limitations: I have not populated the database with standard wall build-ups and U-values. If you're a self-builder or doing major diy hopefully you'll have this info already for your project, otherwise you'll need to look it up manually. There is, however, a comprehensive floor u-value calculator and a simplified one in the room elements input too, so these can be calculated for you. Same thing with radiators - no standard sizes or outputs in a global database yet. I will do a scrape at some point. All outputs entered should be the Delta T 50 catalogue values and if you want system volume calcs, also input the radiator water volume. The UFH sizing calculates volume automatically based on your set pipe diameter, spacing and room area. Text based design - I've tried some of the design tools that are trying to be like cad design software, so you've got do draw your project. Having used cad software, I didn't warm to any of them because they're not proper cad software but in house bespoke design. As I also found out they have limitations so you have to fudge some shapes - roofs in particular. Text based means you can input elements more flexibly according to your needs. Well, I hope so anyway. What you will find different if you've used other tools, although I'm sure they'll either be doing it already or soon, is that the tool provides 2 different heat load figures. is for the heat generator which calculates the whole house fabric and normal ventilation includes a full fabric air infiltration calculation and is usually higher than the generator load To explain this, the new heat loss calculation methods according to BS EN 12931:2017 and specifically those implemented in CIBSE 2026, with wind load under certain conditions, parts of the building and rooms may require higher heat outputs, whilst other parts may need less. This 'total' value comes to a higher result than the generator. In my own test projects that I've run through the new software, I can attest to this working quite well. For example, in one design and installation project of mine, one particular room in the house was designed for 23C but over the winter, whilst never cold, the room never managed more than 21C. I had thought it was a balancing issue, but no. When I ran this project through the new software it predicted that I would need larger radiators in this particular room, base on the new ventilation infiltration calculation, so that is what I will be installing before next winter. Anyway, please have a go and let me know what you think, and ask any questions you have here, or email me at the tool - heatloss@openheatloss.com Does anyone need a user guide to the design workflow and inputs? Let me know..

The battery would be VAT free during the build and maybe VAT free after. They became VAT free (outside of a new build) a couple of years ago and for sure that gift will be removed at some stage in the future. Definitely get the battery when you’re building, they change the game entirely compared to just solar PV. It’s costing us naff all to run this house (and hybrid car) the battery and off peak tariff is a large part of what makes that possible.

It's funny you should raise this difference between heat pump installer and electrician. The electrician I use as part of all my heat pump installations called me a while ago pretty p***ed off. He'd completed a new house wiring installation plus solar & batteries on 3 phase. The heat pump people came along and just installed a single phase heat pump cascade, causing a bit of a headache. At least yours are talking about it. What is the size of your heat pump? And I'm guessing it's been confirmed the model is available on 3 phase? Probably a silly question. I've had a similar experience with solar design for my place where the designer didn't seem to understand modular and phased approach. It's a bit infuriating. With the right system design there should be no problem scaling up if you need to, just as @JohnMo suggests.

Sure, but the law is different here in Scotland - we have a lot more protection when we buy.

Has anyone had any experience with Sips Industries ltd in Fife Scotland? I’ve seen them at the home building show at the Nec, are they any good?

If your putting a battery to cover your whole winter loads, it going to be huge and not cheap. I would size it now for an average winter day. But your tariff makes a big difference to the size, Cosy gives you 3 charge periods, a typical electric car tariff only one, so you would need a much bigger battery. Just choose a battery that can be expanded, add more later if you want as slave units.

You can see the difference between the red/white lines which are the demand on the transmission system vs the pink/red lines which are the actual consumption of homes and businesses (plus import /export etc) The difference is the amount of LV solar &. Wind which are the renewables that operate on the low voltage distribution network At this time of year almost all my instantaneous electrical demand is met by my solar system.

I'm not sure. It is a company but is it one of those weird ones where the Gov is 50.1% share holder?

@LnP I don't disagree with the idea that the high elec price is an issue or that we could do with some sort of reform to bring it down. And pricing intermittently into the renewables price would effectively take the place of the marginal auctions now, though it might help by better ammortising the intermittent gas stations costs with the renewables cost. But I do quibble with a few things.... Yes, better storage would be good but the "long term gas... North Sea" bit is (potentially) a bit more of an issue. The core point of this thread is that UK North Sea gas is running out - even the Norwegians are seeing production falling, albeit at a slower rate than us. So if by "long term gas... North Sea" you mean drilling more to get more gas - nope. I can see (ha!) a potential for drilling new gas fields specifically for providing gas to power stations when they are needed as backup for renewables (sort of storage except we never put the gas in), but that only works of the fields are vertically integrated with the power stations. The UK peak is now down closer to 35GW and we have nowhere near 120GW of renewables capacity (though your point about having to have a greater "nameplate" capacity to peak demand ratio for renewables vs thermal is very true) I would point out that solar can be extremely close to the consumer ie on their roof. This is visible in current data when the national consumption diverge from the transmission load as more LV solar supplies the demand without having to travel long distances.

Isn't the grid completely private? We were discussing this a week or so ago.

We are fitting solar and intended to include a battery system sized to suit estimated use. But our electrician/plumber suggests we leave the batteries until the house is up and running, then size accordingly. I was surprised, as it will take a year until we have reliable figures, and that's a year of not getting the benefit. Plus we will not be getting in the habit of optimising. The vat reclaim entered my reasoning until I twigged that it is zero anyway. Is the electrician wary of estimating wrongly? Or wise? Or perhaps undersizing or oversizing is more than a cash issue. He also agreed we should get a 3 phase heat pump, which the solar people were resisting. On the principle that as we have 3 phase we should use it. Thoughts please,

The EU has rules around government involvement but I don't think they are absolute - the NHS wouldn't have been able to exist otherwise. I agree there could be some market distortions but I'm not sure it would stop people joining unless the government had so much capacity that nobody else was ever needed to generate - but at that point, by definition, we wouldn't need the extra capacity so the problem is moot!😁 Maybe if the government built and owned the storage facilities? Eg pumped hydro and battery. That way they would be creating an additional market for the excess power. Big long term infa like pumped hydro is more suited to government ownership rather than quarter to quarter shareholders. And building big battery farms (or providing lots of domestic batteries) would provide a "prime the pump" investment for UK based battery manufacturing...

Listen to this Dieter Helm podcast... high industrial electricity prices are causing deindustrialization of the UK economy. Energy consuming industries are leaving - chemicals (we now have just one ethylene plant, Grangemouth, left in the UK, after Mosmorran and Wilton closed), ammonia (all now gone from the UK), cement and steel. New investment is not coming in. At the same time, our consumption of these materials hasn't decreased so the CO2 emissions from the UK might have dropped, but they're just being released somewhere else. "To restore industrial competitiveness, Britain needs permanent, structural reform to electricity pricing—not short-term fixes. This requires three big changes: charge industry based on long‑run marginal system costs rather than loading full network costs onto them; reform the electricity market by moving away from gas‑set wholesale prices towards a capacity‑based “equivalent firm power” system that properly accounts for intermittency; and index carbon prices inversely to oil and gas prices to stabilise overall energy costs. Together with improvements in gas storage and long‑term gas supply contracts from the North Sea, these reforms would deliver predictable, globally competitive energy prices to support both existing industries and the more electricity‑intensive sectors of the future." The long term gas supply contracts he talks about are how to address the often quoted reason why drilling in the North Sea won't help gas pricing or security, that the gas is traded at the spot price on world markets. It doesn't have to be like that. When North Sea gas production started in the late '60s and '70s. The Gas Council, on behalf of British Gas (nationalised state gas company at the time), entered into fixed price contracts with the producers for gas which had to be landed in the UK. There's no reason why new gas drilling licences couldn't be granted on similar conditions. That's essentially how it works with renewables CFDs. Locally produced natural gas is much better for the environment that liquifying it to LNG in the US or the Middle East, shipping it over here and then vaporising it again. He also makes the point that renewables are not cheap. They appear cheap because the generators don't have to pay the full system costs - intermittency and grid capacity. To compare intermittent renewables with firm power from e.g. a CCGT, the renewables should be required to provide and pay for the batteries or whatever. Regarding grid capacity, the UK consumes about 45 GW. 60 GW of firm power generating capacity from a few power stations, situated close to consumers, used to be sufficient to deal with peaks. We now have 120 GW peak renewable capacity spread around the grid, remote from consumers and still they doesn't provide all our electricity. Despite that, in the latest off-shore wind auctions (AR7), we had to contract for a strike price of £91/MWh. Renewables aren't cheap.

This is a bit of a 20-20 hindsight thought. The layout is what it is: all neatly boxed in and decorated. For repeat or about-to offenders, I would add ease of access to the tap line as a checklist item. This really wasn't as issue for me during commissions as they were easy to turn then. 3D printing sound like an easy solution -- at least for my son-in-law who has a 3D a pinter -- until you add in the learning curve and hassle of doing the 3D cad etc. for the key (it isn't on Thingiverse). Gemini suggested putting a bolt in the end of a 28mm end-feed cap and using 2-part epoxy plus a greased tap to make a female. I also though about using 22 mm endfeed T and toothing the middle branch as you suggest to form a T bar overkey -- except that Jan had a clear-out, and gave away all my odds and sods plumbing bits on the rationale: "we'll never be doing any more plumbing ourselves, but if nec, then Screwfix is only a 10 min drive away". How do you deal with sticky 10-year old HEP2O manifold jobs?

Battens on top of PIR. If you have ever built traditional with dot and dab and taken off a electrical socket, you will feel the draft running behind the plaster board. 100 boards of 25mm 250m2, more than enough for what I need £1500. 150mm dri therm 32, 250m2 £6000 100mm cavity PIR 250m2 £5400 I’ll say it again though. I build houses everyday and there is no way I’d have PIR in the cavity. I’d rather pay the extra and have 150mm fulfill, 25mm PIR internal and batten service void. 1% extra on the whole budget but much better results.

@TerryE, I think it’s just ‘life’ and would be far less problematic if you had better access to get your kits on it more robustly. Beware using a ratchet as that apply way too much torque and wreck the manifold, but I’d certainly look at getting a long screwdriver and welding on a tip that fits the square shaft, or, as above, 3D print a key. You could probably buy some aluminium tube and just hand cut some castellations into the end of it to create a Hep-spanner. I doubt those teeth would need to be more than 5mm deep vs the full depth of the tap heads. Have you emailed Wavin to see if they do a spanner for this?

I think, when we were part of the EU, there were rules against too much government ownership. Did not stop the French taking over EDF though, so probably a way around that rule (and similar ones here). If a government did own, plan, build, run and sell energy (even at arms length) it would affect the private companies investment plans i.e. why bother when the government can undercut. They could put a capacity cap in place i.e. no more than 20% of the expected 2050 needs. But then they could also change the rules if they wanted to (think student loans and retirement ages). I don't know the answer, and I am sure some clever people are working on it, be interesting to see what happens.

Possibly. No. I mean the government build and operate the facilities themselves. They may (prob will) use private companies to do that but the asset will remain the property of the government and be operated by the government. We used to do it. We used to build and operate national railways, hospitals, schools, even power stations. Whilst there are pitfalls in this approach, it would be hard to argue that the privatisation model eg railways, water, hospitals has been a success on all fronts. Edit: I don't mean PFI or similar - I've been involved in hospital and school PFI schemes and they are often really shit for the tax payer. Not only is the build quality really low, the contractual conditions of the "landlord" are terrible. The power facilities are going to be big enough and around long enough for a corps of efficient government employees to form to operate them.

https://www.goodreads.com/book/show/543682.The_Complete_Book_Of_Underground_Houses

M4 options also reduced ! Sure new models are coming but ram shortages clearly becoming a massive issue

This would make me VERY nervous - you pay out for all the planning application, surveys and reports that may be needed to support the application, it gets approved, and then they pull out, up the price and you can't afford to buy and are out of pocket for the planning. Something needs to be put in place to protect you.

This is part of the reason the system was set up. It may have run its course and now need modifying. While the idea seems good, in principle, private investment would quickly dry up, and/or bigger risks would be taken by the private sector investors on marginal sites/plants/technology knowing the the government would probably bail them out. Financing public services, through private investment has not proved very successful in the past.

3d print a tool to sit over the head like a socket?