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  1. I have a Genvex 185 S that we're having some issues with. We had a service late last year and when the engineer opened the unit it was frozen over, he said the evaporator sensor must be faulty so needs replacing. We ordered the new sensor and waited for the company to return to replace the sensor. On return the sensor was replace (Ice had gone) and the different engineer that came out told me the compressor isn't working. When you turn the unit on, the fans start up after around 10 seconds then the compressor turns on after about 1-2 mins. Our compressor turns on for 5 seconds then cuts out, almost as if it trips. When we turn the power on, the initial startup shows the following; Compressor - OFF Heat.elem. - ON Elec.afterh. -OFF Defrosting - ON Dom. water - OFF Room - ON Add. Cooling - OFF Aux. relay 8 - OFF Aux. relay 9 - OFF After 1-2 mins the compressor tries to turn on and then cuts out, 'Defrosting' and 'Room' change to OFF I seems like the unit is stuck in defrosting mode and causing the compressor to trip on start up even though the evaporator temperature sensor is showing 17 Celsius? Our next option is to replace the main board according to the company, to the tune of over £600. If anyone has any tricks, tips or advice to try and diagnose the issue further, or a supplier of Genvex parts other than Total homes or Xpert Energy that would be much appreciated. Many thanks in advance, Ben
  2. Hello, I am just starting a development of 5, 2 bedroom flats in London E8. I've never installed ASHPs before and as a result I'm nervous. I'll happily use enviro-concretes, clay blocks and good standards of insulation but the heating and hot water systems HAVE TO work 365 days a year. When its freezing and someone comes in, these flats have to warm up swiftly and if they want a power shower straightaway then the water must be piping hot. Part of me says 'Stay with good sized Combi gas boilers', after all until our electricity comes from environmentally sound sources, it's arguably a con to say these are green systems. They use electricity sourced predominantly from gas / nuclear / coal / abroad and that won't change for at least another decade. But okay, if they work I'm up for it. Each flat is 80sq.m. Each will accommodate 2-3 people. Each flat has 1 bath and 2 showers, a dishwasher and a washer dryer. Insulation will be good; part of the building is new, part is a complete refurb with new windows. I'm keen to keep all the internal equipment to a 600 x 600 x 2400mm cupboard. One thing that concerns me is comments such as 'when it's heating hot water the central heating stops' and 'they don't work well on really cold days' and 'they're noisy when they're working hard'. I also need to size my systems correctly - what would you advise? I've come here hoping to be reassured. I want to do this but I just can't afford to get this wrong. The people on this forum seems very knowledgeable but equally no one's saying "I'd install these day-in day-out'...there's always a caveat. I'd really appreciate your advice. Thank you
  3. Afternoon, I wasn't sure if this should go in the renewable section or Scotland section. I was just wondering if there was anyone on here from Aberdeenshire or the surrounding area who has had an ASHP installed. Can you tell me who you used and your experience of the company/installer? Thanks Paul
  4. Hey Folks, Getting quite close to finally pulling the trigger on this build and of course there the many questions popping up in my head every day, especially after browsing this forum each day! The latest niggle in my head is should we have planned to have solar panels along with our ASHP?! Our 290m2 house will have UFH on the ground floor with rads upstairs. Plumber has quoted a 16kw ASHP with a 300 tank (50 litre buffer tank). Bit of a basic question however what would the PV’s (if we had them) be best utilised for exactly? To simply power the heat pump? Given the plumber has quoted a 16kw pump is it asking a lot for PV’s to power such a pump and therefore would it be cost effective? I have also heard people using solar panels for the hot water only? Whatever the outcome we 100% do not want masses of PV’s on the roof, a couple would be acceptable on the integral garage I think. I will admit I am a little clueless with solar panels and their associated cost to install - any figures would be greatly appreciated. thanks again for your help guys
  5. I currently have an outdated oil fired heating system and I need to replace the boiler, oil tank and pipework etc. I have been in touch with a Air source heat pump provider who quotes a flat £14995.00 install for and ecodan 8kw heat pump, 170 litre hot water tank, 10+ rads etc. Having had a survey done I am due to meet with a sales manager to finalise details. In regards to RHI I have been advised I would receive just under £11K from RHI over 7 years. I have a detached 5 bed house and wondered if this is setup would be suitable and if £15K is about right Any advice would be appreciated, thanks
  6. Does anybody have any experience of ASHP from Cool Energy? I became aware of them last week when I visited the Sunamp factory and after looking at the Cool Energy site they seem to be considerably cheaper than a lot of their competitors. I was told at the time that they were not accredited by a scheme that allows you to claim RHI but as it is likely to be included in a smallish house I don't think the RHI payments would amount to much. I know very little about ASHPs so do they vary in performance and efficiency and if so do the Cool Energy units compare favourably and are they reliable? Any advice or recommendations welcome.
  7. I am in the process of building a Passivhaus. As there is no gas, I will be using an ASHP for Heating and Hot Water. Heating will be via radiators located downstairs and upstairs. I am in the process of deciding between two Mitsubishi heat pumps - the 4KW QUHZ (CO2) which is matched with a Thermal store and the 5kw PUHZ which is matched with a Hot water cylinder. I have phoned up Mitsubishi and spoken to them about the QUHZ (CO2 air source heat pump). There is no additional maintenance required for the QUHZ. I also asked them about reliability and there view was that as they've had to increase the spec of the QUHZ in several areas to take into account that CO2 is the refrigerant so they expected the QUHZ to be as reliable or more reliable than the PUHZ. I think there is a big difference in the way that it heats up the water as the QUHZ uses a thermal store rather than a hot water cylinder used by the PUHZ. Not an expert in this area, but research I have carried out suggests thermal stores are less complex than hot water cylinders. Idiots guide from Mitsubishi was to use the QUHZ if your hot water energy requirement exceeds your energy requirement. Using the more detailed data for range of temperatures supplied by Mitsubishi the services engineer checked performance in PHPP for specific loads and temperatures for our house. It indicated that the heating is indeed slightly better with the standard unit but hot water is considerably better with the QUHZ which correlates with the feedback from Mitsubishi. These were both modeled at 45 C heating design flow temp and 55 C DHW supply temp. So on the surface it would appear the QUHZ is better suited to my needs. The only caveat is that it is a relatively new technology for Mitsubishi (introduced 3 years ago) and I think in the market place in general. I had an early condensing boiler fitted to my current self build and it was always breaking down, so I am a little cautious of using anything new on the market because of that experience. Heat pumps seem to be tried and tested technology however so maybe I am worrying unnecessarily. I would welcome any thoughts / feedback on this.
  8. Considering heating options for our renovation project. No mains gas here so was thinking about LPG as it’s clean and a cheaper installation and servicing option. Spoke to a local contractor who suggested that ASHP would be a better option in the long term. He gave a verbal estimate for fitting an 11kw Mitsubishi ASHP. £10-£12k Seems expensive to me. What do you think?
  9. Hi I've recently purchased a 1bed "colony" house in Edinburgh. For those unfamiliar with colony houses, these were homes built throughout Victorian Edinburgh and were designed as homes for the skilled working class, more details about them here if you are interested. Mine is a 1 bed ground floor, 45sqm altogether, with a small front and back garden. It's currently fitted with electric storage heating that I am hoping to remove and replace with a small air source heat pump and install underfloor heating throughout. I found this forum through my ASHP researching and have found it really useful so far. I also want to change the internal layout, so the largest rooms are for the kitchen and living room. I wish to move the bathroom to the opposite side of the house and turn the current kitchen (small, narrow) to a very small double bedroom! This requires a couple of walls knocking down and rebuilt. I won't have the keys to the property until late November so works can't start yet but I'm trying to do as much research before then. Thanks all, looking forward to asking lots of questions as I have them...!
  10. Hi all. First post, appreciate any guidance 👍 We have a Samsung Ashp which provides all our hot water (via immersion when needed) and underfloor heating. We continually get e911 flow issues, and have tested and swapped flow switches to no avail. Having read the some documents for months as can't get a plumber who wants to deal with it, I think it's plumbed incorrectly which may be throwing the flow issues. The switch is on the wrong side of the flow meter, and there should be (but isn't) at least 150mm before any bend or fitting either side, I think. Can anyone clarify that I am correct, or barking up the wrong tree? Setup image attached. Thanks
  11. Hello folks, Given the wealth of knowledge on here I thought it might be wise for me to post up our quote for plumbing our new build and ask the question 'Does everything seem right?' 4 bedroom 1.5 storey house (250 sqm internal) with 3 bathrooms - downstairs (shower/bath combo, toilet, sink), upstairs (shower, toilet, sink), upstairs en-suite (shower, slipper bath, sink, toilet). The quote is as follows: Grants Air Source Aerona 3 16 KW Grants 50 Litre buffer tank Grants 300 Litre monowave heat pump cylinder UFH to ground floor Radiators on first floor Dual fuel towel rails to showerooms Manifold, actuators, pump centre and room stats for underfloor heating Plumbing for ensuite Plumbing for showeroom upstairs & downstairs Plumbing for kitchen and utility room sinks Plumbing for dishwasher and washing machine Plumbing for tap in garage Lead flashings under soles of 2 dormer windows Supply/Fit bathroom suites (6k allowance) All copper pipes and fittings All waste pipes and fittings All gutters and downpipes (PVC) Thermal fluid for heating protection All for the price of £37k (including 6k allowance for sanitary) Is the buffer tank necessary? Any implications of having one?
  12. Hi Folks Looking for some guidance before leaping into E bay. Have spotted a used Samsung 9KW ASHP complete with tank and buffer tank and all expansion tanks and controls etc. Following from the listing:- 250ltr Santon Premier Tank Plus Pre-Plumbed Unvented Mains Pressure Water Heater with wiring. 120ltr Gledhill SL Plus Multi Buffer EE Tank plus pump. Expansion Tanks. Samsung and Siemans Controller Units including wall mounted controller and room stat. Fernox TF1 Total Filter Unit. All Instruction Manuals. However from the limited research I have done on the tanks, they do not seem optimized for ASHP IE larger coil, although I am not certain. Also what is the real world expected service life of the heat pump and compresser. I am planning on using it to run underfloor heating and also domestic hot water, planning on fitting a 3KW PV array. Currently have gas, so new ASHP kit + PV seems expensive/long payback time, however I like being less grid dependant, but need to buy secondhand to justify the costs. No plans to register for RHI. Here is the E bay link The 9KW seems about right when comparing the results from the excellent JS Harris heat loss spreadsheet, it is posibly larger than required, but seems they run better a little oversized. thanks
  13. Because of our budget, there's some hard decisions and trade-offs to be made. Grateful for any constructive comments! Remaining garage size It's a double-length garage - 9m. We could just convert half of it, leaving the front part as a regular-sized garage, but that will leave us tight on space. Instead we're leaning towards taking around 5.5m, making the front part just a workshop and store (and hopefully, micro-brewery 🙂. Floor will be raised by 100mm using PIR with 18mm chipboard on top, and external walls with timber frame and PIR. Roof to be raised by our tame builder. Shower location Due to the 3-gabled chalet roof, there's not many places where a shower can be put upstairs. There's no scope for an en-suite that we can see (unless we shelled out for a dormer, which is likely to be beyond our budget). The only option for an upstairs shower seems to be to move the bathroom wall into the 3rd bedroom, making it smaller still. The other option is to have a downstairs shower room in the garage, but that's then eating into kitchen/dining room space. Kitchen/dining room configuration The existing kitchen is long and narrow, but we aim to widen the room by taking out the built-in cupboards and moving the door back slighting into the hallway We'll then knock through the current utility room The new space is actually larger than the existing kitchen. Do we move the kitchen into the new space and have the dining room where the kitchen is? Could seem a little odd to walk through the dining room to the kitchen, plus we'd have to install a new kitchen pronto as we'd be wrecking the orginal (and that's not in our short-term budget) Would like big (possibly 4m, 5 door) bi-folds onto garden, and a big (3m x 1.5m) roof lantern in new converted space on flat garage roof. Lowest u-values we can afford. Leaning towards keeping the kitchen location where it is, sink relocated to window, and with a small utility room in old garage space Insulation Uninsulated concrete ground floor - which might be tricky to raise and too expensive to lower for insulation. VIPs too expensive to do throughout (but considering 10mm for kitchen) Cavity walls are already insulated Roof insulation needs topping up, and lap vents installing in roof fabric Heating and hot water Existing system is warm air, with electric immersion and cylinder for hot water. Boiler replaced within last 12 months, but the system can't easily be extended into the new conversion space. So we'd need a combi-boiler just for the conversion. Floor drop in garage isn't enough for the insulation that would be recommended for UFH House isn't well-enough insulated for ASHP As a result we're leaning strongly towards simply a new modern combi-boiler and wet rads throughout
  14. Hi! We're buying a 1970's-built 3-bed detached chalet-style house in Bedfordshire. Apart from a lick of paint and a recent bathroom, it's pretty much unchanged since built: Gas warm-air heating (ducts, and lots of 'em) with electric immersion heater for hot water Parquet floors to lounge, hallway and dining room which needs resanding, filling and sealing (plus filling the gaps left when we remove the warm-air heating outlets) 1970s kitchen, including sliding-door cabinets! Our aspirations are: Immediate - Convert current tiny utility and the end of the double-length garage into a new dining area flowing off the kitchen, plus new utility and (probably) downstairs shower room Immediate - Roof lantern and bi-fold doors onto garden in new dining area Immediate - Replace warm-air heating, ideally with something more environmentally friendly Medium term - New kitchen (self-fitted) Long term - Replace tiling on gable ends with cladding (possibly cement board e.g. Marley Eternit) Challenges are: Three-gabled (T-shaped) chalet roof limits possibilities upstairs unless we put in dormers (which we don't have budget for and which would be tricky anyway due to multiple gables) No space to add a shower to upstairs bathroom unless we make the small bedroom smaller and so thinking of downstairs shower Existing ground-floor spaces are concrete floor with no inbuilt insulation Garage floor is about 6" lower and so when we raise floor we'll have to raise the roof too Extending heating to the converted area of the garage - warm-air ducts can't be extended (and we don't think we're fans of it anyway), so thinking of wet under-floor heating in conversion and replacing heating in rest of building with traditional wet rads Asbestos throughout (we've had a specialist survey) including soffits, boiler flue, roof tile underboard, boiler cupboard door, utility ceiling, Marley vinyl floor tiles in kitchen (only the last three of these areas are likely to be touched though) Budget for immediate stuff is £30k. Conversion could be £20k, leaving only £10k for heating changes. Looking for: Bright ideas on heating. Keen on ASHP but as we need new rads could be beyond our budget. Might have to settle for modern combi-boiler Any genius insight or pointers to existing posts on any of the above!
  15. Just a marker for a project thread.
  16. If you install an air-source heat pump (ASHP) to heat your property, it will attract a subsidy called Renewable Heat Incentive, which is a payment to you based on how much CO2 emissions are saved by the installation of the system. The calculation is done on the basis of the guestimated CO2 emissions numbers in your (less than 2 years old) EPC Report, taking potential savings by loft and cavity wall insulation (which you can often get done for free) into account. Naturally that means that if you upgrade your fabric by other methods, and have a new EPC done before you apply, your subsidy will be materially smaller. Here is a comparison for 2 semi-detached bungalows, one with an EPC of 74-C, and the other with an EPC of 44-E. Restored bungalow. EPC: 74-C. Annual energy for heating: 6,577 kWh. Annual energy for water heating: 1706 kWh. Total energy: 8283 kWh. Calculated RHI Payments: £530 for 7 years. Unrestored bungalow. EPC: 44-E.. Annual energy for heating: 12,283 kWh. Annual energy for water heating: 3421 kWh. Total energy: 15704 kWh. Calculated RHI Payments: £630 for 7 years. What to do: Get a new EPC report to document the poor status (about £50), and get your ASHP process done under that rule, rather than doing it later. In the case of the small detached bungalow above, the difference is worth £700. (Cynics Corner: The apparent truth that for such an install done the official way to get the subsidy - via an Approved Installer - seems to cost more than having one by a competent installer who is not Approved, by an amount which takes up most of your potential subsidy-gains, is not to be mentioned.)
  17. I was just lloking into the different systems available for heating/Hot water. Some Great systems are used by the members on here and I am tempted to use a Genvex Combi like @PeterStarck as it seems amazing logical to combine it all with the MVHR. However, i just found this : It seems an incredible good system, even though not including the MVHR , but still a very good, space saving method which seems easy to use/install. Website is in Norge so anybody wanting a look might need to look at their NZ distributor as I couldn t find UK or even US website Anybody on here ever looked into this? Is it a good system, or not really worth the trouble ordering from Norway as similar exists in the uk(which ones>? )
  18. In this entry I'm going to discuss in more detail how I came to choose our heating and hot water system, and how it has performed to date. As other forum members have found, deciding which fuel source and type of technology to use in a low energy house, is a challenge given the different requirements each of us has. We had three stipulations – low running costs, hot water available on tap 24/7 and maintenance of the whole house at an even and constant temperature 24/7. Having calculated our heating demand, taking the impact of solar gain, incidental household gain, human occupancy and wind speed into account, I was confident that I had a good indication of the amount of heating I would need. I was also confident, based on historical use, of the amount of hot water we as a family use. Living in an area without mains gas, my options were somewhat limited to using either oil or electricity as my fuel source. LPG was initially considered but discounted due to the lack of availability in my location. As part of the decision making process, I spent a fair amount of time carrying out a cost comparison of both oil and electricity based heating and hot water systems, using 500kWh increments from 2500kWh to 5000kWh. I considered direct electric of various type, oil and air source heat pumps, both air to water and air to air. Solar PV was also considered and costed in terms of each method of heat and hot water delivery. In line with previous cost comparisons that I had carried out, I found direct electric to be the most cost effective in terms of capital outlay and running costs when both heating and hot water demand were less than 2500 kilowatt hours each year. As heating requirement and hot water requirement increases so the balance began to tip in favour of other technologies. Oil was quickly dropped from the list as it became apparent that any rise in fuel prices over then then low point, would significantly increase running costs. Having conducted significant investigation in respect of the viability of Sunamp units, although attractive in many ways, I found that the capital outlay and running cost was simply too high to be able to justify, given that the main benefit (low heat losses) were not as critical for me as they have been for others. Part of that decision was also driven by the cost of fitting Solar PV, which in our remote location was extortionate. I looked into a non MCS DIY install, but couldn’t make the figures stack up, the break-even point being around 17 years. Much as I wanted to install PV, it didn't make any sense financially. In time, I hope to revisit PV, if and when battery storage reduces the break-even point to a more realistic timescale. A wind turbine, given our location and the virtually constant presence of wind, would have been an ideal energy source and paired with Sunamp technology, probably unbeatable. The proximity of nearby houses ruled out that option in terms of planning permission. Air to Air heat pumps were ruled out based on my own experience of them and a road test at a friends house. Neither myself or my good lady found them particularly pleasant as a heat source. Having gone through the list of options, an air to water air source heat pump, paired with a large UVC and UFH for the distribution of heat, represented the best balance in terms of capital outlay, running costs and crucially, comfort and convenience. We opted for a package from Mitsubishi Ecodan, an 8.5kW heat pump and 300 litre pre-plumbed cylinder fitted with the Mitsubishi FTC5 control panel. Given our location, we opted for the coastal model, which is treated with acrylic resin for enhanced corrosion resistance. Whilst a pre-plumbed cylinder is more expensive than a bare cylinder and associated parts, after taking labour (plumber and electrician) into account, I found there was very little difference in cost. I sourced the package from a trade supplier, Secon Solar. I found their price list while searching online and having phoned the company, and perhaps fortuitously speaking to the managing director of the firm, found they were quite happy to sell me package at trade / installer price, the bonus being that delivery to my location was free. The package is configured for the UK market, the only difference to the system as sold in the rest of Europe (AFAIK) being that the cooling function of the heat pump is disabled so that the product complies with MCS approval for claiming RHI. It is however a simple task to activate the cooling function, by flipping a dip switch in the control module on the cylinder. Cooling can then be controlled from the master controller. As stated in an earlier blog entry, the heat pump and cylinder were fitted very quickly with simple connections on the plumbing side – flow and return from the ASHP, cold water, hot water and flow and return to the underfloor heating manifold. Electrical connections consisted of power to the ASHP, a cable from the ASHP to the control module and a plug-in controller. I had initially planned to have the cylinder in the utility room close to the ASHP Monobloc, but changed the location to a service cupboard in the middle of the house, to reduce internal DHW pipe runs. This does mean a 15 metre pipe run for flow and return to the ASHP, but as virtually all is within the insulated envelope, it doesn’t represent much of an issue, and does not appear to be having an adverse effect on performance. The ASHP Monobloc itself is located beside our back door, open to the elements. It seems happy enough where it is, despite the wind that traverses the space between house and garage walls. Locating the ASHP within the garage itself was an option but one I decided against simply on the grounds that I didn’t want to give up floor space within the garage. A timber housing for the ASHP is something we may look at in the future. We opted to fit individual room thermostats to all 3 bedrooms, to give us the option of being able to reduce the bedroom temperatures if we so wished. We have not used these and keep the whole house at one temperature 24/7, treating the underfloor heating as a single zone. At present I only have limited data as to how the heat pump has performed since moving in. On board energy metering (energy consumed and energy produced) shows the CoP for heating has ranged between 3.5 and 4. DHW is maintained at 47C-50C in the cylinder, boosted every fortnight to 60 degrees by the immersion on an anti-legionella cycle. To date the CoP for DHW is 2.4 As members know, heat pumps are best suited to the production of low temperature heat as opposed to the higher temperatures required for domestic hot water. Whilst the CoP for DHW is lower than that for heating, the cost per kWh of our DHW, based on a CoP of 2.4, is 5p, which is significantly better than an E7 electricity tariff. We may be taking a hit on efficiency, but in reality all of the other options would have cost us more. The 300 litre capacity of the cylinder means that we have plenty of hot water on tap and can comfortably run a full bath and still have sufficient left over for another person to shower. The ASHP is currently operating on a 24/7 basis, providing heat input to the UFH and topping off the DHW as and when it determines it needs to, at whatever flow temperature it determines. Whilst that does sound like a recipe for high bills and high flow temperatures, in practice, the heat pump delivers the lowest flow temp it can get away with to maintain our set temperature. If I so choose, the controller lets me set various parameters such as heating curves or set flow temperatures, or indeed a timed schedule for heating and DHW. However,as the system is operating efficiently on its auto setting, and providing the level of comfort we want, I see very little reason to mess around and create my own settings. If say electricity tariffs were to change from a single tariff to a dynamic tariff, then I would have the option of timing the heat pump operation to coincide with lower rate tariffs. After much thought, and indeed discussion on this forum, I opted for an 8.5 kWh ASHP over a 5 kWh ASHP, as I felt happier running a larger unit more gently than pushing a smaller capacity unit harder. A 5 kWh unit would probably have sufficed, and in time, may be what the current unit is replaced with when it reaches the end of its life. We haven’t yet had to activate the cooling function as any overheating (defined as internal temperatures over 23C) caused by solar gain, can, as modeled, be managed by natural cross ventilation. Neither have we found it necessary to constantly circulate the UFH to even out the house temperature / redistribute solar gain from one part of the house to the other. In the heating season, we found that there was sufficient circulation of the UFH during the heating cycle to maintain the house at an even temperature. Outwith the heating season, when solar gain is at its peak, the house zones itself, the bedroom section remaining slightly cooler than the public areas, very useful on a warm summers day. Overall I’m very happy and impressed with our system. It has, so far, delivered everything we have asked of it in terms of comfort and convenience, and the running costs are low. I have the capability to cool the house (via slab cooling) if I so wish, and the option to bolt on a second zone pack onto the pre-plumb cylinder if I ever found it necessary to install a second heating / cooling function – i.e. fan coil or duct heater / cooler. The one criticism that I have is about the controller thermostat function and its hysteresis - 1C increments only. A finer degree of control would have been preferable. Our installation was recently inspected by an MCS accreditor (our plumber is going through the accreditation process). In due course that will give us the option to apply for RHI, although that will be very much dependant on whether the figures stack up.
  19. I am considering having an ASHP fitted but at some point will want to sell this house. Have people found that having an ASHP has been attractive to buyers, put people off, or they haven't been generally bothered either way? I'm on all electric here so was wondering whether it might be a selling point or the reverse.
  20. Hi, I'm not entirely sure if this post belongs here but there are several components that I think I should consider as part of one solution: Heating and Hot Water. You may be familiar with my project from the introductions forum but I'll present you with my circumstances in any case. I currently have a Combi Boiler heating our traditionally constructed 2700sq.ft bungalow and providing hot water to 2 showers (right now we use 14000 kWh Electricity and 48907 kWh Gas per annum!). We will be updating the current building with thicker loft insulation and better windows, but will still use rads to heat this portion of the house when we complete the renovation. The new part of the house will add around 6000sq.ft and will be built to much better u values using ICF walls and SIPS roof. Here's where I'm confused, I don't know what the best system will be that can provide loads of hot water (7 showers), heat UFH in the new part and also heat the rads in the old part. I'm further confused by mhrv, I've heard this is a necessity in ICF homes, but then heard the speaker at the homebuilding show at NEC state that they're pointless for homes over a certain size. I'm open to installing an ASHP but I'm not sure whether it's necessary or even beneficial when I have the option of mains gas. Lastly, I've a good size roof pointing SE without any shading to speak of so we could potentially generate a considerable amount electricity, but I would have to consider the regulations of having a system over 4kWh and the costs associated, also factoring potential battery storage over and above Sunamp if this too makes sense to use. I don't have a clue where the feed in tariff comes in to all this! There will also be a detached annexe of around 800sq.ft and we will most likely go with UFH and 1 shower, I'm not sure how this should be incorporated in to the overall scheme or whether I should treat it separate. I know its probably a good idea to speak with an energy solutions firm and will most likely speak with Stratford Energy Solutions who have been recommended to me, however, I also know that they may have commercial interests that don't take in to account all of the factors we self builders consider.
  21. Was driving home this evening when I got stuck in a jam on M25, as I was musing out of the window I noticed an ASHP on a farm building and observed the cable tray running from it to the building which, from where I was, looked crowded. It struck me that we have not made provision for the ASHP connections to the new house as yet and that I should get this aspect of the scheme into my head and onto some drawings. It looks like you need to get two well insulated water pipes, inlet and return, one condense drain, one power cable and probably a control cable, which I guess might be CAT6 or something simpler. A couple of thoughts struck me: Is there any limit to the length of the water pipes? Is it sensible to put them, the water pipes, into the slab, insulated, or run them outside the building. (I think that things which look like an after thought, such as pipes outside buildings should be designed out if possible) Can the condense drain run into the soak away or must it be piped to the sewer? Any thoughts anyone.
  22. I introduced myself back in the ebuild days but I've mostly been lurking here since... thanks for all the interesting posts which I have enjoyed reading. For many years it was our intention to self build but failure to obtain planning permission (long shot) and failure to find another suitable plot meant we have settled for a renovation project instead. We dreamed of getting close to passive house standard on a new build. We have been living in our 1950s house in East Devon for a few months now and are trying to make decisions on what to do. Having read so many interesting response to people's queries I'm looking forward to asking a few questions. The highest priority for us is getting some heating, the old Aga that keeps only the kitchen warm has to go and we need something a bit more modern. We have filled the 50-80mm cavity with polystyrene (ThermaBead cavity Carbon Saver), which may have got the block/cavity/brick wall U value down to somewhere near 0.4. The loft has c. 200mm mineral wool. The Crittall windows will be changed at some point. I'm considering a GSHP. Given our EPC's heating requirement is quite large I think the RHI could be significant, especially as we have space for trenches so don't need the expense of a bore hole (we have spring water, I've got some questions to ask on that in another post). My question relates to floor insulation, or the absence of it. The ground floor is 67 sqm which is made up of 40 sqm of suspended floors (living room and dining room) and 27 sqm of concrete floors (kitchen, hall and cloak room). Taking up the suspended floor to insulate is relatively easy. Taking up the concrete floor would be a far less pleasant task. Having attempted to calculate the heating demand under a scenario where the whole floor is insulated verses one where only the suspended floor is insulated suggests it's not that big a difference. We're going to have plenty of cold bridges under the walls anyway. Would it be foolish not to take up the concrete floors and do the full job? Any tips on taking up a 1950s concrete floor?
  23. Due to some of the astounding quotes for UFH and DHW systems, I have decided to have a stab at designing and specing our own system! This is the first draft, possible due to this forum and the Building Services Handbook recommended by @curlewhouse - an awesome book, I've left in the page #'s from where I've done capacity calcs. Even so, a sanity check is very welcome! It's currently a bog-standard unvented system + system boiler that is scaled for the DHW only. You'll notice I'm one of the converted to @Nickfromwales's Hep 20 Manifold setup, though I'm not necessarily sure that the 2nd hot water at 48'C manifold is necessary for us. Principle question here is whether it's safe to pass the output of the UFH back to the main cylinder, or will that have to be discharged? We're unsure as to how we're going to supply heating however, whether we scale up the boiler / cylinder capacity, or whether we go via the ASHP or Solar Panels/Thermal Store. We're looking at ~2100 Watts for the UFH based on our heat losses during the winter here in Oxford. There'll be no other heating in the house save for some electrical UFH matts in the upstairs bathroom. ASHP with a good CoE running overnight to take advantage of the E7 scheme sounds grand, though we're concerned with the noise and another hole in our external wall for this. Could this be plummed directly into the UFH, or would a separate cylinder be needed to store the output? Solar Panels sound grand, but we're concerned the timing of the heating will be at odds with when we'll need to heat the floor. Also, the initial outlay appears quite steep so we'd likely need to install it retrospectively when we've the money. Scale up the Boiler to ~18kW to supply the UFH along with everything else FYI: I used MS Visio 2016 which has several Pipes & Valves stencil sets out of the box. Very useful! Heat Losses calculated thanks to @JSHarris's calculator.
  24. For those interested apparently tonight's episode on grand designs has a Sunamp system in the project
  25. Trade price list as reference point from company I purchased my ASHP and Pre-Plumb cylinder from. Secon Trade Pricelist Sept 2017.pdf