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About Me


  1. Building extension with ICF
  2. Hello I'm interested in installing an ASHP, but quotes from businesses have been very high (£11k to £17k). Ideally I'd like to save money in the long term by switching, so using an installer seems out of the question. I am now considering a DIY install but am not sure if I can. What I wanted to clarify is: Does a heat pump need to be installed and/or commissioned by someone with an accreditation of some kind, or can I do it all myself?
  3. https://www.ft.com/content/b81307f1-94cc-4b0f-9b64-1ac072dfe9dd
  4. Intro: We are (soon) building a Potton SIPS, 2 storey, pretty conventional house in north Wiltshire. It will have ASHP, MVHR, 3.6kW in roof PV. Data: 185 sq m floor @0.15, 210 sq
  5. HI all. Would anyone with some knowledge like to give me an opinion on the AHP60 ASHP. Spec attached. its in conjunction with my other post, so run this to heat a 300L UVC for 2 camping pods. the money is good, brand new 3 year warranty. It is cheaper than the Dream units on ebay. and at this cost is sort of a no brainer unless someone see's a big issue. I've taken into account that parts if not local will take an age from China, but the immersions (on the tank) will be my back up. Might be convinced to buy 2 and use for the house as well... AHP60Spec.pdf
  6. Hi, perhaps someone with more experience than me can help. My gas usage for the last year is around half that suggest by a recent MCS ASHP survey. I really don't want to pay for and live with a double height HP unit if its not needed, but don't want to undersize either. I live in 160m2, 4 storey mid terrace house in Bristol. C 1870 Extended to the rear and loft so half of the exposed walls are essentially new build levels of insulation and air tightness. Floors are fairly well insulated. Mixture of rads and wet UFH. Fully double glazed, half the exposed walls are 300 and 400mm uninsulated solid brick/ stone. as mentioned we are looking to install an ASHP. my measure gas usage does not match the ASHP installers calcs. My figures for heat loss at at -2c are 4- 5kw and theirs come out at ~9kw. (i calculated this from measuring gas usage over the year, used degree days to establish a heat loss per degree difference in/out. then see what it gives at -2c ) Annual usage is equally off. Our gas usage was 9000kwh for the year and the calcs suggest 19000kwh. (no calculation by me on these numbers) For refence that gives a measured value of 56kwh/m2 vs calculated 119kwh/m2 Finally I ran our combi at 40 degree flow for the past winter (coolest average day was 2c ) and maintained 20degree internal temp fine. but the calculation suggest the radiators would only keep interior temp of 20c with flow of 55c and outside temp fo 3 degrees. which would be far from ideal. Do calculator tend to over estimate? I have worked hard to reduce drafts, perhaps the clacs are based on an assumption for an old drafty house ? any advice on if my measured figures seem plausible? The renovation has been done well but not to enerPHit. opinions on whether oversizing or under sizing is the better option welcome. Our primary aim of ASHP is CO2e reduction not financial. Thanks in advance. Joe
  7. I'm trying to figure out what size Mibec twin wall insulated pipe to install as part of the groundworks before I've actually chosen an ASHP or had a proper design. First budget design suggested a 12kw ASHP would be required for UFH (approx 120m2 floor area) and DHW. Pump will be positioned about 10m away from the house and advice elsewhere on here suggested Mibec twin insulated pipe seems are the way to go. But should I allow for 25mm or 32mm pipes to connect from ASHP to the manifold inside the house? Any advice much appreciated.
  8. Well, got the heating on 1st December and the MCS certificate first week if January. The EPC took a while. The online ones were a waste of time so got a local (ish) man in. Although he was very busy so it did take a couple of weeks. Got the EPC the second week in Feb then filled in the online RHI forms and process. Went well except we used the joint build bank account for the payments. Once entered it can't be changed. So the needed verification of the account, inside leg, number of eyes etc. However they are excellent on the phone. A couple of emails and it was sorted. Got the payment detail though today. All in with the UFH (400sqm) and 1500m of pipe in the garden and while we did most of the install ouselves, elecrical, most plumbing and all UFH. it still cost around £35k for the whole heating and hotwater system . Good news that the RHI will cover this over the seven years.
  9. Hey all, Apologies if I'm posting this in the wrong place.... Couldn't find a relevant thread... So we are nearing completion, we have been living at the house ie. using it in a domestic sense, for just over a year. We installed an Air Source Heat Pump and got a loan from Home Energy Scotland. We were assured that the Domestic RHI would pay for our loan. We have our MSC Certificate and our EPC. Ofgem and the Domestic RHI team are completely ignoring all emails from me for some reason. We're hugely aware of the fact that the deadline is coming up - they questioned how many days we had lived in the house, I told them we were here every day using it and the heat pump every day for the last year. I've chased the guy 4 times - no response. I'm on Twitter trying to get through to Ofgem. I'm trying them on the phone but keep missing their opening hours. I just want to find out if they're trying to dodge me, and if other people in a similar situation got the RHI all sorted? I'm starting to worry, as we really can't afford these monthly payments and would DEFINITELY not have chosen to go with an ASHP otherwise... Thanks! Joanna
  10. Hi..I've got the chance of picking up a cheap second hand Heatrae Sadia Megaflo 300L Unvented indirect solar cylinder model cl300 solar. Would it be possible to use this with an ashp for DHW only (heating not required.)?
  11. Since January 5th we have used 222kWh on the ASHP over the last 26 days. That's about 9kWh per day for heating and hot water. However some days the hot water temperature has been boosted by the PV excess power going into the immersion heater so let's assume 8kWh per day for 100m2 home. The heating is running 24 hours a day at an average of 20C. The outside temperature has been low (I will look up the records later) with only about 4 nights of frost. Results from trying different programmes seems to indicate that running the heating all night at about 2C lower than day temperature uses less energy than turning it off over night and letting the building drop lower and then reheating in the morning. Some mornings at 6am it is a lot colder than between 10pm and 4am and I think the ASHP has to work alot harder in a colder temperature a lot longer to enable the house to reach the required temperature. Interestingly, when we were out all day the system used even less power to maintain temperature even though we left it running. Another item that effects these results seems to be the amount of power used in the building almost regardless of the purpose of its use. I will start keeping a record of the whole house energy use to observe the results. Another is solar gain. Others are leaving doors open for extended periods of time, and body heat from things like housework. When we were leaving the heating off in the night I noticed that the north east bedroom became colder than the rest of the house. Having installed the insulation and vapour barrier myself I reason that this is due to wind chill as this is the most exposed part of the building. The ASHP Ambient Temperature probe registered 15.6C two mornings ago at about 9.30 in the morning although it was actually only about 6C. This caused the ASHP to lower its output temperature and the house was a degree or two lower. So I have shielded the probe against direct sunlight and this seems to be working.. The weather compensation mode in the ASHP control system relates the outside air temperature to the ASHP output, in an attempt to produce the minimum heat required to satisfy the temperature required in the building. Set up correctly this will lower the temperature of the ASHP output in line with a rising outside temperature and vice versa. In my opinion, the setting of the weather compensating levels would need to be adjusted for each individual property in order to have any chance of success. Because this bungalow can over heat when the outside temperature is above 10C I have adjusted the water temperatures down in the weather compensation control area. We have not tried out the cold settings yet as the weather has been mild. The coils in the mechanical ventilation heat recovery (MVHR) ducting work well in heating mode. The air from outside , at about 5C, goes through the heat exchanger ( raising the temp to about 19C, then along one of the main supply ducts and through the heated water coil (water circulated from the buffer tank), before splitting up into outlet ducts and entering the rooms at about 26C. The cooling opperation will have to wait until the summer to be tested. Having installed additional insulation around both the hot water tank and the Buffer tank the loss of heat greatly improved. The utility room is now at about 21C unless washing is going on. I am very glad we managed to keep all the tanks etc inside the building's thermal envelope and all the 28mm pipes with maximum pipe insulation. It may be this is long and boring but hopefully someone will read this before installing an ASHP and benefit from my experience. Good luck. M The best combination:
  12. Running all 4 in the winter is quite interesting: PV generation: About a week with overcast skies and then a couple of days of sun. January is supposed to be the low point for PV generation. Based on the EU calculator we should produce about 180kWh in January. We measured 195 which is about 6.3kWh a day on average. However generation happened spasmodically along with the weather. For example 14kWh on a good day and 0.86kWh on a poor day. EV Having the electric car meant that on the few days in the month when the PV generation was over 2kW we charged the car. We use a 3kWh plug in charger. Even with a 5.12kW system on the roof at peak generation during January we only saw a top of about 3kW, so rather than waste (send to the grid) maybe a kW or two we charge the car when generating 2kW or more and reduce the overall cost of charging the car. We calculate that over a ten year period that 1kWh used will have cost us about 10p. Hot water: Most of the excess was captured in the hot water tank using the Solic 200 controller and a 1kW twenty seven inch immersion. Twice even reaching over 60C resetting the countdown timer designed to warn us when the tank has not been over 60C for more than 10 days. MVHR The MVHR is now running smoothly with all controls working. One of the interesting items is the water coils that have been installed in the air ducts. These have increased the inlet air temperature from 17C up to 25C depending on the heating water set temperature and flow rate through the coils. Quite nice to have warmer air into the rooms in winter. Can't wait to use them in summer when cooling the bungalow using the ASHP and powering the ASHP using the PV. ASHP: ASHP kWh use over January roughly 9kWh a day for 100m2 for average 20 C over 24 hours indoor temperature. Had to move the ambient temperature sensor on the ASHP the other day because it was exposed to direct sunlight and effecting the temperature compensating mode. If it wasn't for Build Hub and the helpful contributors I would have struggled with half of this..... Thanks to everyone on here who helps. Many people who are new to the idea of ASHPs will find this a good place to start. Good luck with your project. M
  13. Hi All, We're been living in a new build property for the past 2 years without any obvious heating issues. We've an underfloor heating system that's split across 4 rooms, and is driven by a Daikin ASHP. I've occasionally had to take the actuators off in order to release stuck pins after periods of minimal heating activity, but always noticed that the flow valves show 0 flow when the system is on or off. When pressing the zone pin down, the associated flow meter bounces and a knocking sound is heard through the pipe. After watching a few videos online, I wondered if the system had been connected up around the wrong way, but couldn't find confirmation anywhere. When the system is running, if I manually depress one of the pins for about 30 seconds and take temperature readings off the pipes, I see 37 degrees beneath the actuator at the bottom of the manifold .At the top, I see 26 degrees under the flow indicator for the same loop (see attached photos). Am I correct in thinking the flow into the manifold is around the wrong way? If so, apart from not giving an accurate flow indication, does this cause any problems? The house is certainly warm enough through colder periods (22-23 degrees) but I wondered if the system would be as efficient as possible in this configuration? Any advice gratefully appreciated. Thanks, Ben
  14. No problem with the plumbers work. Just how not to design an installation for the best results..... If ever there were things to avoid, I think there shown here.
  15. Hi all, Any reason the white expansion vessel in the pic could not be moved to above the main tank? I asked for it to go above the tank given we have the room and I was planning to build a partition around the tank and this now is a bit of a rethink with where they have put the expansion vessel. I questioned the location when I came back to site but the installer simply told me it has to be no higher than the tank. Any experience of this on here I'd love to hear comments. Thanks
  16. The general view on this forum appears to be that GSHP and ASHP with UFH should in the ideal conditions be on for most of the time and the room temps set to the required level and not changed. While I understsand the processes and calculations involved in heat transfer and heat loss and the time taken to heat a room with low and slow as opposed to high and quick, what I am failing to understand is why I have been sold as "Ideal for control" for my GSHP supplied UFH a set of expensive all singing thermostats with internet connection that I can set any range of setting from anywhere in the world. When the companies commissioning process recomends all the features are turned off and reduced to a basic stat setting am I correct in thinking I have been ripped off?
  17. Can anyone explain in simple terms what effect adjusting the ASHP compressor and or fan settings will have on the output? Also is the ASHP pump that people have referred to mean the pump circulating the water? The ASHP involved is the Cool Energy inverTech Air Source Heat Pump CE-iVT9 4.3kW-9.5kW. Thanks for your help. M
  18. Ater a good dicussion with a local plumber it is pretty certain that we will be putting 2 ashp systems in to supply 2 zones, but they will both be in one area next to one plant room. The idea is that 1 big pump (15kW)would be working very hard, whereas 2 x 10 would be coasting and much more efficient. Therefore the feed from the plantroom will need long distribution pipes to the manifold. Ground floor concrete with ufh. Partial First floor is largely in the roof space with timber floor and will be big rads. There will be a convenient void between low walls and the outer wall, through which services can run, and we can insulate inside the stone wall. I think we must take the feed pipe to the first floor so that it can be insulated or we will lose too much heat in transit in the concrete floor. Is it normal or wise to use the specialist insulated pipes, or simply to use normal pipe then pipe-wrap (the superior one) then also wrap in mineral wool. This looks great but is £50/m, and it might be difficult to get round corners. Have used it previously outside from distant ashp to building but is it too much for inside? .
  19. There have been lots of discussions about the effectiveness and efficiency of an ASHP and so I am keeping basic records. I have my own electric meter on the supply to the ASHP so I know how much power has been used whether from the mains or the PV. The result so far using the ASHP installed is 123 kWhs have been supplied to the ASHP from Jan 1 to Jan the 21st to heat the building and hot water. As it is difficult to split the power used for hot water (and we have an immersion using the excess PV power on the hot water tank) from the power used for heating if we assume all of this power was used for heating that would equate to an average of roughly 2.6 Watts an hour per m2 of floor over the 20 days. Normal living with 2 people, showers, average 20C inside all day. Last night -2C outside some of the time. Used in the last 24 hours: 12kWh's. Whilst we are happy with the results now being obtained, I would like to point out that the results were completely different when we installed the ASHP, when the very thick lagging was missing and we were using it like a boiler! Good luck with your endeavours. M
  20. I moved into a 4-bed dormer bungalow (176m2) last summer that had just been gutted, extended and completely renovated, including ASHP for the DHW and UFH. The ASHP is a Nibe F2040-8 (8kW). The UFH is in screed downstairs and on aluminium trays in the suspended floor upstairs (both with 200mm pipe spacing). There is no buffer tank, although there is a volumizer unit. Room temps are set to 18C for bedrooms and 20C for the kitchen/lounge etc (no night-time setback). The UFH downstairs can maintain target room temps with a flow temp of 25-35C. However, the upstairs seems to need a higher flow temp of ~45C to maintain target room temps. The problem with this is that when the outside temp falls below 5C, the ASHP continually defrosts and is unable to deliver a flow temperature >30C (i.e. the opposite of the intended weather effect compensation!). I have attached some screenshots of plots from my Nibe Uplink – the first is when the outdoor temp was ~10C, which shows the flow and return temps oscillating around the target flow temp (which is what I would expect to see) and the other shows the same plot when the outdoor temp is ~2C. In the latter plot, the pump is defrosting so frequently that the flow temp never achieves its target, resulting in high electricity consumption (>£200 p/m), a really noisy pump, angry neighbours, and room temps <18C upstairs. The installer is refusing to investigate this problem and Nibe will only interact with installers. Q: is the impact of the defrosting cycles what you would expect for an ASHP at <10C? If not, any thoughts on the underlying cause – insufficient pump size? Lack of a buffer tank in the design? Anything else you can think of that might cause this…? Looking forward to your expert input and happy to provide any additional details that might be helpful.
  21. Well the combo is coming together and my wife insists that I make the controls as clear as possible "in case your not here". I wondering what she means. Still a lot to do though..
  22. I'm having a number of problems with a shiney new Daikin Altherma 3 installed in September (COP down at 2.5 already with intended SCOP of 3.7; radiators cold at the bottom hot at the top; system pressure keeps dropping). I've emailed the installers a couple of times and got no reply, so this week I'm going to start phoning them up. So I don't get fobbed off I'd appreciate some advice on three things. 1. There's a red expansion vessel, and a white Zilmet VSG Solar temperature reducing vessel (pictured). It looks like all the CH and HW is passing through the Zilmet. It is in the loft and permanently warm so I was thinking I should insulate it. From reading up it looks like this is designed to limit the heat from solar thermal, which can be as hot as 90C. But I don't have solar thermal and no intention of getting it. I have CH running at 45C and hot water around 50C, once a week 60C for the legionaries program. So isn't this thing just wasting heat as it's in the loft, not living space? Is the effect any different from leaving some pipes without lagging or could it actually have a useful purpose? Rather than me insulating it I think they should just take it out. 2. Part of the install was a brand new 125L indirect HW cylinder. From the max temp of 54C, it will drop to 44C within 24 hours, even if I avoid turning on any hot water taps all day. Is that heat loss normal? I thought modern cylinders were only supposed to lose 1-2% heat per day? 3. I have had to refill fill the system several times, because pressure drops from 1 bar to 0.2 bar within a week. I can't find any leaks from the radiators or pipework. So I guess the pressure dropping might be an expansion vessel problem? One thing I don't need guidance on though is whether they've put the unit too close to the walls. The Daikin installation manual says this outdoor unit should have at least 250mm clear at the back and side. It's been installed with 140mm and 160mm, so I am going to insist they move it, and will complain through MCS if they refuse. Lack of airflow has got to be contributing to poor COP. Thanks for thoughts on the above.
  23. Good morning all. This is my first post so please point me in the right direction if I've posted in the wrong place, asked a question that's already been covered or broken the forum rules. I bought my house around 5 years ago and I have slowly been renovating it ever since. About 3 years ago I had an Air Source Heat Pump installed, as we have no mains gas and at the time, the RHI was generous (it paid for the system). Last winter I picked up an absolute bargain of 4kw solar panels with an inverter for £400. I installed it myself and I am mostly happy with it. Since then I have changed the inverter so I can connect via bluetooth. Recently i have had a smart meter fitted.......... Now that I have the smart meter fitted I can see exactly what the power I'm sending back down into the grid. Actually, I knew this before, but its different when you can see the display 'laughing' at me!!! After the install, I did contact an MSC company and ask them if they would inspect and certificate. They told me, that it was virtually impossible for them to do this as they had to provide proof of where the panels came from. In any case, they said I'd only get about £60 a year back from the one or two electrical suppliers that offer a feed in tarrif (5.5p per KW). So......I was thinking, there must be a smarter way of using my solar and ASHP. I have my heat pump set for 21degrees in the morning and evening and all other times it's set to 18 degrees. There is an 3kw immersion in the tank, but it's only used to prevent legionnaires disease. When the heat pump is on it draws around 1.5 kw. At the moment, the heat pump thermostat/programmer is not wireless and I am not able to connect to it via bluetooth. I was thinking that maybe if the sun was shining during the day and producing over 2kw I could somehow activate the heating to go up to 24 degrees. This would warm the house during the day and therefore require less heating after the sun sets. Obviously, I would need some kind of app or software to run this. My ASHP is a Mitsubishi Ecodan and my inverter is an SMA. Thanks in advance for your replies, Nathan.
  24. Based on info on Buildhub I estimated a 15kW ashp, but a local specialist says it is not enough. Also the floor arrangement requires a secondary feed and manifold to reach the distances. The building will be in the form of a main building and an annex (for us old ones and b&b). Plans below shows the layout, with central courtyard. All the GF to be ufh. The upper areas (front and left wings in roof) to be radiator (headroom is tight). Outside is 21 x 19, inside 18 x 16 approx. Insulation will be very good, to new-build targets, although some trading off for practicality (esp headroom at existing doors), so the floor will be 125 to 150 PIR. Our thoughts are as follows. 1. 2 pumps needed so do they both feed the one plant room or 1 for main build and 1 for annex? 2. If the former, do they work in tandem or split to space heating and water heating? 3. Split the load as 2 identical pumps sharing the load, or large and small? 4. Best to have 2 water tanks anyway, for volume and to avoid arguments between the 2 spaces? 270m2 GIA ground floor, 110m2 upper floor. The plant room is shown, to the left next to the stairs. There is a roof void at bottom right that could house more plant. BTW the current favourite installer seems good, but it is early days and I like to understand and question. Any comments welcome, not just as my 1-4.
  25. Hi - got my ecodan R32 installed in October and it's been purring away ever since quite nicely. This morning, in Edinburgh anyway, it was near on 0 degrees and there was a noticeably louder noise coming from he unit, as if the fans were spinning much faster etc. I gather it's normal for an ASHP to work harder, and therefore be noisier, when it's cold? When the manufacturer publishes its decibel rating, is it best case or worst case - i.e. on a lovely summers day when doing a DHW top up or at -5 degrees in winter? Thank you in advance!
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