oranjeboom Posted July 5, 2018 Share Posted July 5, 2018 11 minutes ago, Triassic said: Great thread, thanks everyone for all the contributions. ln my own installation I’m going for a Sunamp for my DHW, if I coupled this to the PV array described by Nick (above), why, in a well insulated house, do I need a ASHP? Well that's the approach I have gone for in my non-passive, but well insulated renovation/extensions. I was going to go for an ASHP to cover me for the winter demands when my 3.8KWh PV is 'down', but now I have gone for two UniQ eDual cells (24KWh) to provide me with DHW and space heating (UFH). This will mean I am totally reliant on electric (and may go for Economy 7 meterage but didn't want to be forced to adopt a smart meter). I want to see how the house performs this winter and then adapt things next year if required. I may also opt for non-gridded solar PV installation later on. 1 Link to comment Share on other sites More sharing options...
PeterW Posted July 5, 2018 Share Posted July 5, 2018 Just now, oranjeboom said: may go for Economy 7 meterage but didn't want to be forced to adopt a smart meter They can’t insist now - it’s not in legislation so they are stuffed. Saying that, the Octopus energy deal with the potential of 0p/kWh is tempting ...!! Link to comment Share on other sites More sharing options...
newhome Posted July 5, 2018 Share Posted July 5, 2018 15 minutes ago, PeterW said: They can’t insist now - it’s not in legislation so they are stuffed. Saying that, the Octopus energy deal with the potential of 0p/kWh is tempting ...!! How long before we are told that the tariff is higher with no smart meter? Bit like paying a higher tariff for paper bills. That won’t have anything to do with an economy tariff or not though. If energy companies are going to be fined for not meeting smart meter targets you can be sure they will be looking at punitive measures to ‘encourage’ customers to take a smart meter. Could even be a condition of moving provider in the future I guess. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted July 5, 2018 Share Posted July 5, 2018 @AndyT, I may be better asking this directly of Sunamp, but I was one of the very early adopters, and have one of the very first Sunamp PVs. Part of the deal was that Sunamp wanted to have the option to examine the cells/heat exchangers after a time to see if using softened water had any impact; they were going to send me two replacement cells so I could swap them over and send the old cells back for examination. I've had an ongoing problem with sporadic over-temperature trips on the resettable thermal trip on the heater block (my unit has the very early firmware that I believe doesn't have a run-on period to reduce heat-soak) and I've already had to replace the thermal trip in an attempt to cure the problem (it hasn't fixed it - it still trips once every couple of months or so). It seems that the newer unit has completely removed these issues, and as I have been contemplating getting some add-on cells to increase the capacity of our Sunamp PV, I'm wondering if it might be worth changing it for a new unit? 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted July 5, 2018 Share Posted July 5, 2018 2 minutes ago, newhome said: How long before we are told that the tariff is higher with no smart meter? Bit like paying a higher tariff for paper bills. That won’t have anything to do with an economy tariff or not though. If energy companies are going to be fined for not meeting smart meter targets you can be sure they will be looking at punitive measures to ‘encourage’ customers to take a smart meter. Could even be a condition of moving provider in the future I guess. The energy companies will have a big problem if they try that. The chap that came out to do the site survey to install a "free" car charging point told me I couldn't have one because there was no mobile phone signal. During the course of the conversation he revealed that this also meant I couldn't have a smart meter (not that I wanted one) as with no phone signal they can't function. There's talk of adopting power line signalling I believe, to get around the problem of areas that have no mobile phone coverage, but I've not seen any sign that they intend to roll this out. Link to comment Share on other sites More sharing options...
PeterW Posted July 5, 2018 Share Posted July 5, 2018 So the metering regs require them to make a physical inspection of the meter and it’s registers a minimum of once per 12 months. This is their biggest cost and smart meters don’t remove that. The “benefit” is they get more accurate readings but tbh it’s not ideal. SMETS1 was a joke in terms of standards, SMETS2 is better, and I would only really trust one or two of the meter manufacturers with the security of the data. The big issue is the metering data all goes through one big aggregator and that system is the same as it was in 1998.... Link to comment Share on other sites More sharing options...
newhome Posted July 5, 2018 Share Posted July 5, 2018 Just now, JSHarris said: get around the problem of areas that have no mobile phone coverage, but I've not seen any sign that they intend to roll this out. True, but they could just make it a condition ‘in areas where this functionality is available’ I guess. Link to comment Share on other sites More sharing options...
newhome Posted July 5, 2018 Share Posted July 5, 2018 2 minutes ago, PeterW said: So the metering regs require them to make a physical inspection of the meter and it’s registers a minimum of once per 12 months. The current regs? No idea when mine was last inspected. The meter readers just take a reading and mostly I’m out so they leave a card and ask me to take the reading and pin the reading to the door or a window so that they can take the details the next day. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted July 5, 2018 Share Posted July 5, 2018 On 05/07/2018 at 08:25, PeterW said: So the metering regs require them to make a physical inspection of the meter and it’s registers a minimum of once per 12 months. This is their biggest cost and smart meters don’t remove that. The “benefit” is they get more accurate readings but tbh it’s not ideal. SMETS1 was a joke in terms of standards, SMETS2 is better, and I would only really trust one or two of the meter manufacturers with the security of the data. The big issue is the metering data all goes through one big aggregator and that system is the same as it was in 1998.... There is only one benefit to suppliers from fitting smart meters, and that is so that they can introduce flexible on-demand tariff changes, to remove the risk they carry at the moment from having to guess what the mean spot market wholesale cost will be for up to a year ahead when setting tariff rates. Right now the wholesale cost of electricity varies half hourly from a negative price per kWh in low demand, high generation, periods, to well over 20p/kWh during peak demand periods. The suppliers want to introduce variable tariffs to suppliers, using the smart meter and it's internal house display, to both set the meter tariff at any time and tell the customer what it is. This sounds reasonable until you look at how customers are going to be able to compare suppliers. With tariffs changing on the fly there will be no way to easily tell if one supplier is offering better value than any other. 1 Link to comment Share on other sites More sharing options...
willbish Posted July 5, 2018 Share Posted July 5, 2018 3 hours ago, Triassic said: why, in a well insulated house, do I need a ASHP? Because an ASHP could charge your PCM34 (DHW preheat) with 3/4 times less electricity than using the grid when the sun aint shining. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted July 5, 2018 Share Posted July 5, 2018 2 hours ago, JSHarris said: This sounds reasonable until you look at how customers are going to be able to compare suppliers. With tariffs changing on the fly there will be no way to easily tell if one supplier is offering better value than any other. Except the government told them to simplify the tariff structure. I am not sure how it is all going to work. When I work out my price per kWh, I look at the total price, so include VAT and meter rental. Since I have fixed my immersion heater and 'gone back to normal', my all in price works out at 17p/kWh, which is not too bad really. Sometimes, like two days ago, I only used 4 kWh, and only 59% of that at night. That makes it an all in price of 22p/kWh. Roll on winter and I will, on paper, get really low kWh price. Link to comment Share on other sites More sharing options...
Pete Posted July 5, 2018 Share Posted July 5, 2018 Trying to get my head round all this. Now that Sunamp make a unit that will do DHW and UFH is there a need for an ASHP? I realise that the ASHP could provide a means of cooling a near Passive/Passive house and charging the Sunamp. I think I can cool my house quite considerably using the chimney effect and for when the sun is not shining how much will it cost to buy/install and maintain an ASHP and how much electricity could you buy with that amount to top up the Sunamp when the sun is not shining? I think as some are doing on here it may be a case of living in the house for a year and then deciding if we need an ASHP to supplement the Sunamp. I am waiting for a quote from Sunamp so hopefully it may become clearer then.? 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted July 5, 2018 Share Posted July 5, 2018 3 minutes ago, SteamyTea said: Except the government told them to simplify the tariff structure. I am not sure how it is all going to work. When I work out my price per kWh, I look at the total price, so include VAT and meter rental. Since I have fixed my immersion heater and 'gone back to normal', my all in price works out at 17p/kWh, which is not too bad really. Sometimes, like two days ago, I only used 4 kWh, and only 59% of that at night. That makes it an all in price of 22p/kWh. Roll on winter and I will, on paper, get really low kWh price. Simplifying the tariff structure and introducing variable tariff rates based on grid demand/wholesale spot market prices seem to be mutually exclusive. Mind you, nothing would surprise me anymore with any proposed edict from government; they have shown time and time again that they just do not understand how markets work, and frequently blunder around interfering and having the opposite effect to that they intended. The chaotic and complex pricing structures we have for energy, telecoms etc, are all a direct consequence of a government desire to give us all more freedom of choice... Link to comment Share on other sites More sharing options...
Dreadnaught Posted July 5, 2018 Share Posted July 5, 2018 For me planning a near-passive-house new build, the following quote suggested that a SunAmp model with UFH pump and maybe other parts of a UFH circuit included (I suppose an expansion vessel is unlikely?) may be arriving soon. A potential central-hearting system in a box. Could be ideal for my needs. "Forthcoming availability: Fully-integrated Sunamp HydrobloQTM incorporating system pump and other hydraulic functions". Source for quote, https://www.sunamp.com/wp-content/uploads/2018/06/Leaflet-1-Sunamp-Dual-Port-Heat-Stores-Technology-Description-final.pdf Link to comment Share on other sites More sharing options...
Dudda Posted July 5, 2018 Share Posted July 5, 2018 14 minutes ago, Pete said: Trying to get my head round all this. Now that Sunamp make a unit that will do DHW and UFH is there a need for an ASHP? I realise that the ASHP could provide a means of cooling a near Passive/Passive house and charging the Sunamp. I think I can cool my house quite considerably using the chimney effect and for when the sun is not shining how much will it cost to buy/install and maintain an ASHP and how much electricity could you buy with that amount to top up the Sunamp when the sun is not shining? I think as some are doing on here it may be a case of living in the house for a year and then deciding if we need an ASHP to supplement the Sunamp. I am waiting for a quote from Sunamp so hopefully it may become clearer then.? While the new SunAmp is an obvious improvement the range of options now available, (HW, eHW, rHW, Dual, Dual+i, eDual, dPV, ePV) has made it a little more confusing, at least for me. If you want the future option of getting a Heat Pump I believe you need to get a SunAmp which can later connect to an ASHP from the start. If you get an electric only SunAmp you won't later be able to connect the Heat Pump. The other issue is the Dual SunAmp for heat pumps only has an electrical heating element for the PCM58 and not for the PCM34 as that would be charged by the heat pump. Therefore if you install this SunAmp and don't connect it to the heat pump you'll need to ask SunAmp to put in an electrical heating element for the PCM34 (at least that's what I'm having to do). They're incredibly busy so having trouble getting this exact information from them but that's my understanding at the moment. Link to comment Share on other sites More sharing options...
willbish Posted July 5, 2018 Share Posted July 5, 2018 59 minutes ago, Dudda said: you'll need to ask SunAmp to put in an electrical heating element for the PCM34 That's what I've opted for, seems sensible to have the redundancy if the heat pump goes bang in mid winter Link to comment Share on other sites More sharing options...
newhome Posted July 5, 2018 Share Posted July 5, 2018 1 hour ago, Pete said: Trying to get my head round all this. Now that Sunamp make a unit that will do DHW and UFH is there a need for an ASHP? Would RHI payments be a reason to fit an ASHP to offset some of the cost? Link to comment Share on other sites More sharing options...
Triassic Posted July 5, 2018 Share Posted July 5, 2018 Has anyone costed the various options lately as this may help with some of the decision making? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted July 5, 2018 Share Posted July 5, 2018 1 minute ago, newhome said: Would RHI payments be a reason to fit an ASHP to offset some of the cost? Depends on how much heating the house needs. For us, RHI would have paid a bit over £80 a year for 7 years. The additional cost of having an MCS approved ASHP install was around 25 times greater than this, so it would have cost a great deal more to have an MCS (and hence RHI) approved installation than we would ever have got back. The same is usually the case for any new build, even one just built to building regs, as the RHI scheme really only makes sense if the house has a high heating requirement, so mainly applies to older, less thermally efficient, homes. 1 Link to comment Share on other sites More sharing options...
PeterW Posted July 5, 2018 Share Posted July 5, 2018 As @JSHarris infers, there is a sweet spot for RHI... You have to hit a bare minimum to qualify for RHI, and then its at its maximum level for payment as it is supposed to supplement your heating costs to bring them in line with those of more efficient properties. In reality, you can get RHI at its maximum level, then install decent windows and loft insulation and basically take the money and run.... no-one ever checks !! 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted July 5, 2018 Share Posted July 5, 2018 RHI was really intended as a replacement for solid fuel/LPG/Oil in older properties. Wasn't really for new builds, they should be on gas if possible. None of government backed schemes are really intended for a new self build. Too many variables. Link to comment Share on other sites More sharing options...
newhome Posted July 5, 2018 Share Posted July 5, 2018 12 minutes ago, SteamyTea said: they should be on gas if possible. I wish! Interestingly the LA next door to mine installed ASHPs in some of their social housing properties in off gas areas. http://greennetworkforsocialhousing.energysavingtrust.org.uk/CaseStudy.aspx?cid=1149 There were complaints from some residents that the noise was ‘like torture’ apparently Link to comment Share on other sites More sharing options...
Russdl Posted July 5, 2018 Share Posted July 5, 2018 Back to Sunamps (ish) and working on the assumption that the only stupid question is the one that wasn't asked ? Would the combination of a Genvex Combi and a Sunamp be ridiculous (price alone?) The Genvex prioritises hot water with the heat pump and then gets on with its MHRV job, as I understand. Can the Genvex hot water temperature be dialled down to make it more suitable for UFH and as a pre-heat to a Sunamp and if so what are the reasons why such a set up would be ridiculous (price alone? I bet there are more) I guess the Genvex would have to go to a higher temperature every so often to prevent Legionella? Standing by... Link to comment Share on other sites More sharing options...
AndyT Posted July 5, 2018 Share Posted July 5, 2018 13 hours ago, JSHarris said: @AndyT, I may be better asking this directly of Sunamp, but I was one of the very early adopters, and have one of the very first Sunamp PVs. Part of the deal was that Sunamp wanted to have the option to examine the cells/heat exchangers after a time to see if using softened water had any impact; they were going to send me two replacement cells so I could swap them over and send the old cells back for examination. I've had an ongoing problem with sporadic over-temperature trips on the resettable thermal trip on the heater block (my unit has the very early firmware that I believe doesn't have a run-on period to reduce heat-soak) and I've already had to replace the thermal trip in an attempt to cure the problem (it hasn't fixed it - it still trips once every couple of months or so). It seems that the newer unit has completely removed these issues, and as I have been contemplating getting some add-on cells to increase the capacity of our Sunamp PV, I'm wondering if it might be worth changing it for a new unit? @JSHarris, seen the email to AB cc'd ET AT, AB is on holiday ATM so will (I guess) reply on his return. 1 Link to comment Share on other sites More sharing options...
AndyT Posted July 5, 2018 Share Posted July 5, 2018 10 hours ago, willbish said: Because an ASHP could charge your PCM34 (DHW preheat) with 3/4 times less electricity than using the grid when the sun aint shining. @willbish did not clock you were in Brisl - me in W-s-M - but i guess you already sussed that out. Link to comment Share on other sites More sharing options...
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