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So this isn’t like for like, you need to add the cost of a typical gas boiler, the installation of a gas supply and then the annualised servicing etc of both. That gives you the Total Cost of Ownership. Comparing the two as you have doesn’t work unless you do this as you have compared Capex to Opex. Average life of a heat pump is far in excess of 10-12 years as there is very little to go wrong inside. As they don’t create anything corrosive or products of combustion they also don’t need anything like the servicing of a gas boiler. You can also do it yourself if necessary unlike gas. We’ve done this before .. a heat pump will support as much hot water as you need. Sizing the system is the issue, it’s when installers don’t survey the property and assume the 180 litre hot water tank is “enough” for a 4 bed house. What isn’t understood is that the tank is acting as a buffer for usage in a gas fired house, and the boiler will be kicking in pretty quickly once 2 showers are running. If you don’t believe me, turn a standard boiler set up off (Usual 25kW boiler/210 litre tank) once the tank is at temperature and get 2 showers running. You’ll be out of hot water in about 8-9 minutes. The boiler kicks in and is essentially acting as a 25kW instant hot water heater into the tank. The downside with ASHP (unless you go very big) is they can’t provide the speed of recovery as it’s 25kW vs 12kW, so will need twice as long to recover. That is why you oversize the tank. 400 litre tank is £2-300 at most more than a 210 litre tank so in the scheme of things is negligible. Back to Capex - you’ve paid for it as part of the build so what’s the issue ..? If they U.K. standard for new housing was the same as Southern Ireland and the zero carbon targets then we wouldn’t have this issue moving forward. I guess this was a retrofit under one of the “schemes”..?? A lot of these were done by people who used to fit solar panels, cavity wall insulation before that .... and they are neither heating engineers or specialists. I’d hazard a guess it was poor design that was the issue here not the heat pump. Bit like complaining your Ford Focus can’t beat a Ferrari off the lights ... In the lab yes, on test rigs yes, they have less than 3 years real world data of actual usage and the biggest change is changing the jet on the boiler. Been doing this for 40 years with LPG so it’s a no brainer but .... it’s not as clean as you think it is...!! Burning anything in pure oxygen is fine, it’s 2H + O = H2O plus some nice heat. Then add all the other stuff in air, the nitrogen compounds are still there, just ask TfL about this with their hydrogen buses. Your other issue is the problem of transportation and detection. You add mercaptan to natural gas to make it smell, and the reason is so you can find leaks. Our natural gas network is leaky ... but the volatility of natural gas (the nice methane mix) is much lower than hydrogen. So we will need to work out how to stop that lovely hydrogen leaking out as it’s a tiny molecule not the massive long chain hydrocarbon - welcome to the situation where you “could” use hydrogen in a standard boiler with a new jet and a pressure change, but 80% of the infrastructure to get it there would need updating. Assertion.. Assumption..? Or a blind guess ..?? If you size the heat pump and the radiators to the heat load and heat loss of the building, then any building can be heated with a heat pump. If you don’t believe me then you may want to check what an aircon unit is and how they heat places such as exhibition centres with them and not gas boilers (hint, they are heat pumps) Are they ..? 9kW heat pump with all the bits is change of £4k, cheaper if you buy non-inverter. The £10k you’re usually quoting .? That’s the “MCS Premium” for installation to get RHI and it’s not rocket science to install a heat pump. As a balance, I’ve seen quotes of £3,500 to install a gas boiler into an attic plus £1500 for a new hot water tank so they are comparable in price when you consider any plumber can fit a heat pump, to work on gas you are required to be GSR. On what basis are they “bad for the environment”..?? Burning of fossil fuels is bad for the environment, and you’ve completely missed the “how to create hydrogen” issue as you need energy to split the water in the first place to fuel your hydrogen generation. So you are going to take clean energy I take it (ie no fossil fuel based generation) and then use it to inefficiently split water (which you will have to purify first, possibly even use reverse osmosis) then inefficiently compress the hydrogen (using energy generated from..??) then add the smells etc, and finally transport through an upgraded network to a property where you will inefficiently burn it to produce heat and create combustion products ..? That is environmental impact of a massive scale in terms of creation, storage and transmission of a volatile gas that still hasn’t got a fully proven long term benefit. Just so you can use that lovely box on the wall you have always been told is the only way to heat water...?? Or alternatively I can use a transmission network that currently exists to move electricity from existing generation plants that could be produced from any source, to power a heat pump that creates no emissions without having to change anything in the grid infrastructure. And you call my heat pump bad for the environment ..??

Don't think it is, I posted up the government report on it. Here is a bit from my favourite comic. "One stumbling block any hydrogen energy revolution faces is storage and transport. Hydrogen molecules are so small they can leak out of containers, meaning pipe networks previously used for methane may have to be upgraded before they are fit for hydrogen." And that is before the inefficiencies are taken into account. It is much easier and cheaper to reinforce the local electricity grid than the gas grid. I think people have a desire for hydrogen because it is similar to what we already have, but this is missing the point completely. And if you combust hydrogen in air, you get oxide of nitrogen as well as water. Nitric acid is not nice stuff. Makes sulfuric and carbolic acid seem as mild as soap.

Important thing to note here: when you make hydrogen by electrolysis only about a third of the cost comes from the electricity, there are some pretty big costs associated with the plant, storage, distribution, etc. Even if the electricity was free, you're looking at 10p/kWh for green hydrogen once the infrastructure is fully developed. In reality it'll be more expensive, since the plant costs are so high that you won't only run them when there is surplus electricity on the grid. Fag packet maths, based on the Passivhaus standard because it's easier: 15 kWh/m2/year for heating, or 10W/m2 peak load - in reality the two are usually pretty close so let's assume that the notional "well insulated" new house hits both standards. Make it a fairly large house - 200m2 to make the maths easier - and assume that hot water use is also 15 kWh/m2/year which seems to be a reasonable assumption for a reasonably efficient system. 3000 kWh/year for hot water, 3000 kWh/year for heating. 8.2 kWh/day for hot water, plus **peak** heating load of 2kW → 56.2 kWh/day, requiring a 2.3 kW heat pump to satisfy it. Round up to 3kW. COP assumed to be 3, so compared to resistive heat only the saving is ~4000 kWh/year. At 20p/kWh, that's £800/year saving from using a heat pump. Even if you oversize to a 5kW heat pump, you're looking at paying £3k for a monobloc unit → 4 year payback time. Assuming you did go for a 5kW unit, it would be running at full power for 600 hours/year to provide sufficient heating - just under 7% of the time - and the same amount again to provide hot water. If you have a more efficient or smaller house - and particularly if you can use less hot water - then the payback time will get longer. I'm really struggling to see a heat pump not making sense though.

?? I'll be leggin it out of there if they do. In all seriousness tho I don't think they are dodgy, I think they might even be which recommended... it's more whether the product is decent enough for the cost. It's always more difficult to tell when it's an independent sourcing their own cabinets and doors from a manufacturer rather than retailing a specific brand.

wise choice. Looks a lovely plot.

If you build up as the OP, using plywood or osb sheathing on the inside of the frame, you don't need an additional vcl as the sheathing does this job and then you just need a breather membrane on the outside, this is particularly the case if you're using a vapour open insulation. AFAIA there is not requirement in building regs that you have to have a plastic vapour control layer, it depends on your buildup. You simply need to ensure that the internal side of the wall is sufficiently less vapour permeable than the outside. No, you don't need an extra layer of plastic between the ply and the stud as you're using a different wall buildup than is being suggested by @Marvin who is suggesting a traditionale wall buildup. You are using what is called a reverse wall. If you decide to put your plywood on the outside of the timber frame instead, then you would need a plastic sheet. With your buildup, taping the joints is fine. If you want independent reference, have a look at this article that explains the differences in wall buildup and why. https://www.architectsjournal.co.uk/archive/the-breathing-wall-is-a-simple-concept-but-often-confused-by-linking-it-only-to-particular-wall-constructions-all-timber-walls-breathe

I’ve done this many times before Especially fast moving commercial TF If it’s traditional just lap the boards past 50 mil Then trim once the windows go in Weve just done a show home with no widows or casings and slimed the window walls to a taped edge 100 mil short of the edge The customers will pay me to send someone to plant the heads and reveals Then tape and joint Just leave the window walls in skimmed But you will have to pay him a couple of man days to come back and pick the window walls up

Yep, don’t do it, wait.

I agree with your plasterer.

It is sealed off like Royston Vasey at the moment. A camp has been built between PZ and Helston for the extra security staff, helicopters and extra police cars about. Almost like London after 7/7. Drains and lampposts have been inspected and tagged, and the larger potholes in the A30 repaired. Still wondering who is going to fly into Newquay, or Lands End International. Probably into the Base at Culdrose. Except a plane crashed near there the other day. I would have put them all at Lands End, then just cut that bit off from everyone. One road and two footpaths, easy. And plenty of space to land helicopters.

He will know, was he ex Holman's. I used to know Don that run the food bank. Good bloke. Camborne, Pool and Redruth was known as CPR, been renamed to Camborne, Redruth and Pool. CRAP. There was a sign up for over a decade that said 'Pool is the Future'. It was modified a few days after installation to 'Poo is the Future' noone put it back. Just left it there for 10 years. I think they will be bypassing the area when the G8 is one. They even put the Communication Centre in Falmouth, an hour from Cardis Bay. Heartlands is 20 minutes from there. But why show them one of the poorest places I Europe. Show them the vibrant, pretty but.

No issues doing this in 110mm. With bathrooms, you could bring up a stub stack with a dirgo instead of lots of separate connections. If possible I prefer to have the below ground outside the footprint so you could look at having a run on the right for the future bathroom and coming across the front to the main run.

Outside to inside: Cladding Batten Tyvek Thin ply Studwork Insulation and services in studwork. Plastic sheeting Internal finish say plasterboard or ply or OSB. There are discussions about the plastic required by building regs but not mandatory for sheds

This (in green) is the sort of thing I had in mind. All WCs on main runs. Stick a rodding eye at the end of the long run if it exceeds the max length of a run according to BC. You don't need to angle your runs at 45º. You can approach the IC at 90º and have a short bend right next to the IC to hit the socket (bends are allowed so long as they are right next to the IC). And note that, while bends are best avoided in general, bends of <30º are generally allowed away from the IC in long runs if they are required.

Well done with the drainage, and sorry Soleplate and bottom rail of the tf needs to be insulated outboard, worst case is condensation on top of the dpc! ruberised dpc, is available not sure about vcl

That looks a good make up.

I often think that if MVHR had 200mm diametre ducts, a lot more could be made if it.

Have you heard of a company called MacSalvors? They are in Pool. Always worth a call when you are stuck for stuff. And well worth a visit if you are in the area. Pool is real Cornwall, not the nice picture postcard bit.

From the same website. "Average prices shown are based on the supply of fuel volumes suitable for a medium-sized domestic property (around 16.5MWh of annual heat demand), quotes taken from suppliers within the East Midlands region" So very limited in scope. You really have to establish your own energy usage and prices. Luckily though, a kWh is a derived unit of energy, so no need to convert that bit.

My house was PHPP calculated to be at the 15 kWh/m2/year energy loss threshold. In reality it's slightly better than that due to making the most of solar gain. But I still need a 6.5kW heat source at times to maintain 21 degrees. ie. when it's been overcast for several days and the average temperature hasn't got above 0 degrees. I didn't at the design phase, nor do I now feel that the peak heating demand could realistically be provided by an electric heat exchanger in the MVHR and some electric radiators. And combine that with the need for Hot Water, an ASHP absolutely makes sense. That is based on a Big 6 Standard rate for electricity of 19.43p a unit and a 2011 "best" COP 2.7, and the result is 2.7 times more than gas. At an actual 11.725p per unit of electricity and an average COP of 4, the ASHP cost comes down to 2.93p per unit - slightly cheaper than gas.

I have a SSR roof and have experienced no problems. If my memory serves me well my make up is as follows (inside to out) PLasterboard Battening (service void) VCL 18mm OSB Wooden I Beam/380mm with full fill cavity insulation (not PIR) 18mm OSB 50mm battening (vent/void) 18mmOSB Roofing membrane SSR

He’s hilarious ..!! He’s the one that starts talking about chipboard floors and glued down carpets from memory being a reason not to fit bigger radiators... This is the WB Heat Pump page btw - they are spending millions investing in the technology. https://www.worcester-bosch.co.uk/products/heat-pumps Just to save you looking, they quote the following : I though you said they were expensive and would fall apart ..?? And are expensive to run...?? Seems WB disagree with you too - as to 99.9997% of the population ...

So I can run 3 bar at point of use and get hot water to 3 taps at 8 litres / minute from a heat pump based system. Find me a gas combi boiler that can provide 3 bar pressure and 24 litres / minute...? (BTW you won’t find a domestic boiler that can do this, the maximum flow from WB largest combi (8000 Life 50kW) is 20.3l/min at delta 35°C so around 43°C delivered to save you looking and the PRV reduces it to 2.1 bar max so you won’t get close. ) So if we are comparing apples and apples, your combi (which is around £4K installed now for the WB 50kW) has a lower overall pressure capability and lower flow rate to what I am describing so it’s not “zero problem” it’s “you can’t get close” No such thing as free electricity... and you can’t power a heat infrastructure with a variable power source. The U.K. has the ability to store very little of its natural gas supply so is beholden to the European pipeline interconnectors for supply. Unless you convert the whole of the European network to hydrogen, you’re needing TWh of gas storage to provide supply sureity and at the time you don’t need gas ..!! To use the hydrogen created in the summer due to excess solar (your scenario) on a November evening you wound need several million cubic metres of storage as an inter seasonal store. Localised combustion of any fuel as a reliable and environmentally friendly heat source for domestic properties is a rapidly diminishing option, and you’re hanging on to this hydrogen powered combi argument based on outdated opinion and conjecture despite being presented with facts time and time again.

I believe you may have had a badly designed instal which makes you believe they all are. You cannot tell me mine is useless because it’s great, cheap to run and very efficient (and I designed and installed it ?). My build was not very expensive , insulation and attention to detail is cheap.

I have a 1860 Victorian end terrace, nothing fancy about it. just that I have year on year as general building improvements have taken place I have improved the thermal performance of the building, to lower running costs, for my old age when I will be living off my pension, and no doubt energy will be an expensive commodity. Not sure why things need replaced every 10 years, my office has its air con still working after the install date 21 years ago. well installed and maintained equipment will last.

Or to turn on heat pumps, large industrial refrigeration, charge batteries, planned maintenance shutdown on other generation. You just don't understand the inefficiencies of hydrogen, it is like shutting down half your generation capacity. When a wind or solar farm is designed, there are two numbers that are used. Installed Capacity, MWp Generation Capacity, MWh. They are different, but both are known, it does not come as a surprise when night falls that PV stops generating, or that wind is variable. Because these things are known, the actual estimates are very accurate. You can, if you care to, look up the day ahead estimates and see how good they are. But you won't.

Ha Ha Ha Ha Ha Ha

You forget this is a self build forum where people build well insulated houses or recon their existing house to good levels. Not when you consider having mains gas installed into a new build plot (my heat pump was not very expensive) No, I had no gov subsidy. P.S. mine runs very well, cheap to run and very happy with it ? I believe they are not suited to all houses , those that are not insulated and very leaky. Also there are many installers that do not design the installation properly (several on here) which gives them a bad press. RE hydrogen, the jury is still out on that one .

Best insulate insulate insulate and get that air test from 6 to something of 1 or under. then any heating source will cost a negligible amount to run

I guess yours was a badly matched install then. Works fine for me with a family of 5 and 450m^2 house You've not considered how much hydrogen may cost, should they ever work out how to produce it in the volume that would be required to heat homes. The future will be better insulated and more airtight homes with a mix of hydrogen and heat pumps. Heat pump prices will come down, hydrogen will be more expensive than gas.

@Dave Jones has a hatred for heat pumps, but will never quantify his assertions.

Yup, that’s it.

9mm on the roof might even sag over time and you'll end up with washing up bowl like depressions where the water will sit.

In my opinion it’s because the majority of us consider the United Kingdom to be our country and don’t want it split up.

Did look down the route of ASHP, it was going to add approx 10k to the build unfortunately. Possibly short sighted but decided to stick to gas and up spec insulation to pass SAP so no renewable energy needed.

I did not plan any steel penetrations but got lucky with a few gaps but also had a few detours.

+ 1 to @Bitpipe comments. Fitted ourselves as per design from BPC. If you have any steel beams you may need to consider access through them for services. We planned for some MVHR ducts and plumbing but not sufficient space for all the MVHR ducts. Had to avoid the beam with a huge detour via the roof void resulting in longer runs than planned. Works fine - was just another problem to solve.

DIY and I'm not particularly handy. Lots of information on this forum on how to do it. Start with a design from one of the suppliers based on your floor plan - I used BPC. You'll be looking at an extract per bath/kitchen and a supply per bed and otherwise occupied room. Depending on your build method, you may need penetrations in steel beams for the duct runs - these need to be specified, designed by your SE and fabricated, not a thing to be doing on site. You then fix the ceiling plenums where needed and run duct from there back to the manifold locations, one for extract and one for supply. It's easy enough with pozi joists but be prepared for a bit of swearing. Best done with a helper but I did mine solo. Next job is running large bore duct from the internal manifolds to the unit and running the external large bore ducts from the external vent locations to the unit location, insulating if required. Once ceilings are up and plastered (I recommend trimming the ceiling plenums before skimming) you attach the vents, position the unit, attach the large bore duct, run the condensate drain as appropriate and basically switch it on. Your electrician should make provision for boost switches if they're to be wired in - ours were done inline with the lighting controls and use the same PIR trigger as the hot return system. You can then adjust the ceiling ducts to balance flows and check you meet the BR requirements - again, lots of guides here how to do that. You will need to borrow or hire a flow meter. Try and get your ducts in before first fix starts or you may find space taken up with other large services such as foul drains.

Thanks for the feedback chaps, will discuss with the council - just useful to be able to say that I've had feedback regarding the amount of time for HMRC response.

It is a very difficult and overwhelming process. So, make a cup of tea/coffee (fully caffeinated!), sit down with a large notebook and pen. Step1: Buy Chocolate digestives. Step 2: Get on Amazon and order The Housebuilders Bible by Mark Brinkley. Step 3: Read the whole book at least 3 times, accompanied by said chocolate digestives. Step 4: Read every post and blog on this site. Step 5: Read them all again. Step 6: Work out how much money you can reasonably spend. Step 7: Assess your own skill set - are you going to be able to complete any of the work yourself? Be honest. Step 8: Assess how involved you want to be in the process. If you just want to be handed keys at the end, your extension will have to be smaller than if you are willing to pitch in and can actually be useful. Step 9: Ballpark figures - £1000 (low end finishes) to £1500 per square metre of finished home. Use the figure from Step 4 to work out how big the house might be. Time invested now is cheap - delays and poor decision making whilst mid-build are expensive and sometimes not possible.

Welcome @joe90 is mid century.

That is how I refer to plumbers collectively too!

How long ago that all seems. The architect came back with essentially the same design but with a pitched roof - making the house a chalet bungalow. I had told them that I was happy to remove a bedroom to reduce bulk but they said it wasn't necessary. I really liked the look of the new house - flat roofs were never a choice I was completely happy with but merely to give choice for solar panels. Anyway... Planning went in early November and was accepted by the end of the month with a decision date of 15th January. January came and went, as did February, March and April. We phoned, our agent phoned and emailed. We were told that workload was a real issue for the planning department - oh how we sobbed for their poor little paws, grinding away at their WFH desks, not actually giving us a decision on our planning. In the end, on Tuesday this week, I emailed a complaint to the council complaint email address, copying in my two local councillors and my MP (Sir Chris Chope of the Upskirting fame ?). By Tuesday night I had a response from one of the councillors promising to investigate the next day. My complaint had a bit of background and then ... My questions are therefore: Why bother having a decision deadline if there is no attempt to meet it? How long can we reasonably be expected to wait before a decision is made? What are the consequences of us starting work now due to your inability to make a decision? I believe that we have now reached the point where your silence can be accepted as approval by default. You have failed to reject the application, therefore it is passed. What recompense will you offer for the ridiculous delay? We have requested a telephone call so that we can at least have a discussion about the likelihood of the application being successful – the chance to put things right if the outcome is going to be rejection. We hear nothing. We offer an extension – gratefully accepted but the extension deadline comes and passes with no news. You are playing with peoples lives – it is immoral and a failure of your core duties as a council. Under the freedom of information act, I am now formally requesting a detailed breakdown of: Number of applications made for each calendar year going back to 2017 (and year to date for 2021) The average number of days an application had to wait between submission and acceptance for each of those 5 years and for this part year to date. The number of applications that were decided upon earlier than the deadline date The number of applications that were decided upon later than the deadline date The average number of days late for all late decisions, per year, for each of the 5 years and one part year. The average number of days early for all early decisions, per year, for each of the 5 years and one part year. For all rejected applications: The number of applications from developers The number of applications from self builders / home owners The number of applications that councillors had declared an interest in. For all approved applications: The number of applications from developers The number of applications from self builders / home owners The number of applications that councillors had declared an interest in. The reason for requesting this information is my need to see if all members of the public are treated this badly or if we are a special case. We just want to get on with our lives and we are getting to an age where time is against us and we may not be able to actually build our house due to the delays we have encountered. I knew I was stirring a hornets nest but figured I had little to lose. The response was fast and furious - by Wednesday evening the agent (architect) had received the (non) decision notice... You are hereby advised that the Council has invoked its power under Section 70(a) of the Town & Country Planning Act (1990) to decline to determine your application. In accordance with the legislation, your application is regarded as withdrawn and no further action will be taken in respect of the proposal. There is no right of appeal against the Council invoking its power under Section 70(a). We will arrange for your application fee to be refunded. If you wish to submit a further application for the replacement of this dwelling, you are advised to use the Council’s Pre-application advice service first in order to ensure you are addressing the reasons for the dismissal of the previous appeal. This will involve a significant reduction in the height, bulk, floorspace and footprint of the current proposals in order to comply with green belt policy. So we now have NO planning permission in place for any dwelling on our site. The agent has never heard of the council (he used to work for them) deciding to decline to determine the application. Chope has responded sympathetically (but with no offer of helping to stop the nonsense that goes on in council offices) stating that regardless of the outcome, the council could and should have made the decision months ago. Then to make things even weirder, I get an email from the planning enforcement officer offering to come and speak with me to move things forward. We spoke yesterday and it seems they were worried I was going to start building the house that we got planning permission for in 2017 that expired during the time of waiting for a decision. He totally understood my frustration of course - but advised us to go for pre-planning advice - oh how I laughed! I explained the waiting time for pre-planning advice and the futility of asking for advice from planning officers (we have 50+ years of local government service between Peter and I to know what planners are like). Next step - hornets nest is already angry, probably worth adding to it so the next FOI request will be how many times have the council declined to determine an application and also a SAR to see what they have in their records about me.

I fitted mine ? It is pretty straightforward