Forget Octopus, where would the industry be without you? You’re like a national asset and certainly the reason I’m going to be getting a heat pump in a couple months.
I have watched EV Nick for years - good luck to him - whole thing looks like a lot of effort and it’s clearly important to him. Hope it runs well and efficiently soon
Like your intelligent and informed and rational user analysis of these heat pump issues. Very valuable for those like myself who are considering installation soon.
Given Nick's social media presence, I'm sure Octopus will be learning all the time and monitoring his system like a hawk to get the best out of it. His install is on the worst case scenario end of the scale due to the position of the pump and the primary pipe run length + microbore, so very interested to see how the performance improves following the recent changes. This install has massive publicity implications for Octopus and the Cosy 6 so I'm sure things will be put right. Octopus offer one of the cheapest installs around at the moment and there is a lot riding on the success of this install. Nick is effectively being one of the guinea pigs given he's one of the first installs and certainly the first on TH-cam that I am aware of. Nick's a great guy for sharing his install and Octopus are a trusted company, so I'm sure it will turn out right in the end.
You're genuinely the only person I see calling out the REAL problems in the industry. I loved the ones on Dale Vince and the 'critiques' of Everything Electric videos. Some of these companies and people (Octopus included) gain a cult following and can do no wrong. I'm so glad you call it out when you see it.
Useful input to the discussion. I am weighing up the possibility of replacing a boiler in a new house and matching or beating the gas cost by using a low overnight tariff and large battery to power a heat pump. More information is always good, thanks!
I’m sure Octopus Energy are learning a massive amount as they roll out their new ASHP's. They are a reputable company and I have every confidence they will get there.
Totally agree. Have read how they have dealt with other customers who have had issues after installs and the positive takeaway is that they do respond and work at resolving any issues which raise their head.
I know of a case where Octopus had to do a swap of a 9kw to a 6kw. It turned out that the heat loss calculation had loft insulation a zero and not 30cm.
@@bryanhindle8307 Also issues with having to design a system based upon 'MCS Calculations' (Should you want the BUS grant) which are inflexible. We were allocated the 9kw unit which would on paper be perfect for around 15 days a year, yet operate inefficiently for the other 350. Gladly our Surveyor understood this and helped us make the tweaks to get the 8kW unit allocated.
I've heard people say an over-sided heat pump is bad, but I've never known the reason until this video and its that the compressor can only run so low 👍
It's the same with gas boilers too, though doesn't have quite the same impact on efficiency as on a HP. For some reason i've got a 34kW boiler with a minimum output of 4kW and my heat loss is about 3.8kW at -3.1c so it cycles like mad.
according to the spec mine has a ~3kW minimum. also lists the lower 26kW and higher 35kW output versions of it and all three apparently have the same minimum 🤔
@@fairtomiddling I think they make 1 actual product then in the firmware range rate them. Happens in HPs too, the Valliant 3.5kW and 5kW are the same machine but one is firmware limited.
@@UpsideDownFork I use the lower limit because my smaller rooms don't really heat up if the flow temp is too low. So in autumn or early winter the flow temp needs to be a little higher, but then it doesn't need to go up much in cold weather or the room temps will overshoot. Essentially, in my house it's probably something like 25 Degrees at +10°C and 30° at -10°C or thereabouts. We only had a minimum of -13°C last winter so I don't know if my Arotherm will actually ever need to do the full 35°C.
@MCSMIK it's at 2.4 currently. I'm not sure how useful that is as it only made it to 3 degrees outside for a short time today. The cop is going up, so I'm assuming it is lower as its heating the house and water tank for the 1st time?
Got our Cosy 6 just over a week ago. 8m primary run outside, probably 22m total. A volumiser fitted from the start as we have 10mm microbore. SCOP so far is 3.1, which is slightly disappointing. Octopus are sending out an engineer to check everything. The installation team were superb. Once we have our solar and battery in a week, the SCOP will be less important...
It has been a cold week, so don't fret too much so far. Like you say, solar, battery and tariffs can bridge that gap easily as well! Just a side note, SCOP is over the course of 365 days. Any other time period is referred to as COP 👍
Octopus fit a volumiser as standard. In Nicks case they then converted it to a buffer. It's just a case of changing pipes to it and adding a water pump.
@@bryanhindle8307 why do they do that, do you know? It’s like £100+ of volumiser that may not be needed if you did the volume calculation for the pipework and radiators. 🤷🏻♂️
The issue is that it should be calculated beforehand. It's not hard to calculate, its what HeatGeek do (my HG did it). Sure there are border line cases where the volumiser may need to be a buffer and have a secondary pump but I think on Nicks, with microbore, its dead obvious it needs to have a buffer and higher flow temp. I think a lot of OE installs in the future will have buffers and high flow temps as it runs closer to a boiler and simplifies the install. Whether the rates OE will offer will counter the inefficiencies in that, I've no idea. There is definitely a balance to be struck on higher temps vs upgrades and better efficiency. I paid an extra £500 to have my primaries upgraded as they were borderline for running 30-35C flow temps. I could have easily designed the system to 45C and not needed to pay, but over the lifetime of that pipe work, its pretty sure to pay for itself with the savings I get and improved SCOP.
I’ve submitted a planning application using Cosy 6… but the more I see things makes me wonder if I should ask to change to a Daikin. I have solar and battery storage. I would love a heat pump that runs at 500-800w. Seems like Cosy 6 will use way more than that and keep starting and stopping. We run our boiler at 36c most of the time and if the cosy 6 wants to run hotter… it’ll be guaranteed overheating stopping and restarting. Or any I wrong?
@@MCSMIK just took a screenshot of our Cosy 6 app and we seem to be running in the low 100's of W at the moment. Shame I can't attach them to this message...
Yes I did find it curious that Nick was offered a Cosy 6 while I have been offered a Daikin Altherma 4kW (my heat loss is I think a little more than 4kW). It might be that the form factor of the Cosy 6 wouldn't really work at my property. I didn't ask about the Cosy 6. I like that it uses a more environmentally-friendly refrigerant but I think its efficiency is a tad lower than what I should be getting, although mine is a low temperature heat pump. For me it's 10mm copper tails to the radiators and I think they tee off a backbone of 22mm copper. The surveyor mentioned a buffer tank; I'm happy with that; the space it's going into is unheated and it would be good to take the edge off that unheatedness! Anyway I've still got to get my front elevation drawing done before I can submit the planning application which is a bit of a pain but I'm dealing with it around work, selling a second house, and watching youtube videos 😂
Stop watching my videos! That's an order 😂 The daikin units are tried and tested so no worries there. Good luck with your planning, hopefully it goes as smoothly as ours did!
The Daikin also uses R32 refrigerant, allowing it to be placed closer to doors and under windows etc, I believe the cosy 6 is R290 (propane) which has to meet more stringent criteria.
@@_Dougaldog You're right on all counts and the plan is for mine to be placed under a window; there are also air bricks around the proposed location, and all of these design constraints would have factored in.
Cool to get your take. I also follow Nick and am hoping for a heat pump in the future. Disappointing he didn't share any numbers given the title of the video. Hoping we can learn more soon
Not to be unduly harsh on Octopus but assuming Octopus know what they're doing and are doing a competent job is possibly not a true reflection of the situation. We gave up with Octopus after banging my head against a wall about heat loss calculation, system design etc etc. And this is in a relatively new home that's fairly straightforward. It seems like they can do what they can do, just a simple somewhat basic installation. Ended up going to Heat Geek. It costed more but I was happy with that with the long term view in mind.
Night and day difference between Octopus and HeatGeek. No way a HG would have installed it like that in the first place. I'm not sure if Octopus were swayed by Nick, but they/he got far too many things wrong. That long a run, with the heat demand and microbore was never going to work open circuit. Was always going to need the buffer and a second pump. He also set the flow temp far too low. The temp is what is leaving the HP, not what is arriving at the main circuit, then microbore restricting the flow meant it was never going to shed the heat it needed to. Low to mid 30's flow temp is usually reserved for UFH or for those with massive/deep rads/very low heat loss. I have a 4.5k heatloss @ -5C with UFH and can only just get away with 30-35C flow rate at design temps. Currently in negative figures outside its taking a flow temp of just over 30C to keep the house warm.
The ability to modulate to a very low power is crucial to my planned system which I will run on solar and batteries. 2kW is far too high. It is interesting that manufacturers rarely give low modulation numbers. I am looking into an Aira system - they do give modulation numbers - down to 578w for 6kW and 759w for their 8kW unit. This will work well for me. Plus, Aira make a great looking heat pump !
@@andrewbradley4261 2kw is the minimum heat output, not the electrical input. You'll find the Vaillant Arotherm Plus 7kW modulates down to about 450W electrical input and the 7kW is approx 550W 👍 These details are rarely in the single page datasheet but are available in the full technical documents. In the case of Vaillant, that's a 295 page bible.
@@UpsideDownFork Thanks, yes - just worked this out with another heat pump. Confusing - possibly HPs should be labelled as 7-2 kW (heat) and 1.75-0.55 kW (elec.) ?
Would have been interesting to see whether 32mm pipe or even say 42 mm pipe would have produced better results on the external run rather than a buffer tank, you get the volume of water but less resistance or turbulence in the water up to the TEEs or manifold. And why no one has designed a nice insulated tube for exterior pipes defeats me.. just off to the patent office!
I think you’ll find someone has thought of the pipe. I saw something on an Artisan Electrics video covering a job at a big property with 2 very remotely located HPs. Fancy place and no expense spared. Probably why Octopus aren’t using it! 😊
I’d love to see a comparisons of the Cosy 6 vs the Aira heat pump. They kinda offer the similar commercial approach but Aira is more of a they take responsibility long term.
I have a feeling that Octopus are optimising their heat pumps differently from other manufacturers. What Octopus want is the mass adoption of heat pumps, heat efficiency is only part of that. They need something that will easily replace a gas boiler in as many homes as possible. Higher temperature running means lower flow rates so this will work with existing pipework and easy-to-do radiator upgrades. Pipework upgrades are hard. They only need a COP greater than 2.5 because Octopus offer tariffs where electricity is about 1.5 to 2.5 times the price of gas (e.g. Cosy about 13p electric vs about 6p for gas). Octopus want as much data as possible (including extremely detailed data from a known customer subset) so that they can plan and run better energy company and influence the grid of the future. I'm damn sure that high instrumentation with as much data as possible sent back to Octopus, is a key need.
@@Lewis_Standing difficult to speculate without knowing more detail but from what he's shown of his house in videos, I doubt the microbore is much of a restriction.
The cosy 6 max flow rate is 21l/m. As he has microbore and a long run, their default build for Cosy 6 is to install a hydro split and another pump to handle the central heating side.
@@derongalloway OOoo, where can I get my hands on more Cosy data like the flow rate? Also, why does octopus use the term Hydrosplit when they install a buffer tank? A hydrosplit would be when the outdoor unit does not have it's own circulation pump. The Cosy 6 is a Monobloc heat pump with a circulation pump inside it which has now been hydraulically separated from the heating circuit by a buffer tank.
Getting a Cosy 6 in early Jan, could not afford to go for a premium solution with BG or a Heat Geek along with the Solar and Battery install I'm getting in Dec. Boiler is 20+ years old and would be 3 grand to replace. Octopus quoted 1.8K for a Cosy 6 install with the trunking. Everything was pointing towards going Daikin 4/6kW but I did just fancy giving this Cosy 6 a punt (when with my heart not my head), I like tech & new shiny things, I work in a technological field and happy to roll the dice that the app, features and tariff's may improve overtime just for the fun of discovery.
I'm sure you'll be fine. Octopus are just about to vacuum up a LOT of running data from existing installations as the weather turns. They have a lot invested in this and as the biggest retail supplier of energy in the UK, they won't let it fail.
I have a Cosy 6 installation early next year and they have added a volumiser into my 3 bed semi 2000-built house. I believe the Cosy 6 has an expansion tank built into it but I wonder if the distance the buffer tank is from the house has to do with his issues?
My issue with this mass selling of heat pumps is the fact they will not design the system to be below 50 degrees flow temp, even upon request. This will affect the efficiency of the system massively, people won’t save anywhere near the money on energy they could be and the tech gets a bad name. Just had a Viessmann 151-A fitted running at max flow temp on 40 degrees and it just sips the electricity. Coupled with the 13.5 kWh GivEnergy battery, the whole things is costing a fraction of what the gas boiler did. Happy days!
Good move! It's a shame. Octopus did used to offer lower design flow temp upon request but it seems in their quest to speed things along that has been binned.
Biggest issue is the outside location. The designer should never have agreed to that location especially given they knew nick would be vlogging it. Octopus put a volumiser in on all designs as default. I asked mine to be removed and they said they wouldn't.
@gmuzz Volumiser gives a store of warm water to be pumped back into HP during defrost cycle (reduces chance of radiators cooling), there will also be a bypass valve between flow and return just after volumizer allowing sufficient flow (@ 20l/min ?) for defrost cycle should the TRVs on some or all the radiators be shut off. In that respect it serves a different purpose than that of a buffer tank whose primary job is to allow an additional pump to be fitted on the system (pump in monoblock not enough ooomph) without the pumps fighting against each other to control flow. At least, that's my understanding 🙃
@@UpsideDownFork its more that they haven't checked if it's needed - it's just what they do as standard. From an engineering perspective the proposed system does not need the extra volume. It's all 15 and 22mm pipe and they're adding in 28mm for the main run. The existing rads are either too big or being upgraded. I'm paying for something I don't need. Or in octopus's belts and braces/ cookie cutter model they are under designing and over specifying and taking more of a financial hit
I’m just getting quotes for a HP. Getting big differences in some of the specs. 🐙 are only changing a few rads which are similar to what I have but K2 (50deg flow), British Gas are quoting for massive rads for the same rads, (45deg flow) and another company are leaving all rads as they are but using a high temp HP (55deg flow). Pricing the extra rads at over £2k (rads only, the install is extra) I’m trying to justify the outlay when the amount of electric used may be minimal over a year. Any thoughts?
I could have massive unsightly rads and a huge bill (£7k after grant) but good efficiency or smaller but normal looking rads from octopus and lower efficiency - went with the latter and also had a small solar array and 10 kWh battery installed for 6k total. The battery more than makes up for the less efficiency and will be useful all year round.
Properties with a lower heat loss can comfortably get away with 50 or 55 degree flow temps with not too much worry because the overall consumption will still be low. If your properties heat loss is high, then it's definitely worth looking at lower flow temps as these upgrades could pay for themselves in a few years. Sorry it's so variable and individual that it's hard to give specific advice but for me, I really wanted that 45 degree flow temp and was prepared to accept the rad changes that came with that.
I like that octopus would still fit the heat pump where Nick wanted, @UrbanPlumbers has recently fitted one further away than this, why loose garden space when you have that dead space with lots of airflow. Also I like how octopus monitored the system and came out to fix the system, a lot of cowboys would be a nightmare to get back if you contacted them. Have you ever looked at your past gas usage to see how many kW you used over a winter to compare to electric usage now? Or are there too many variables with hot water, hob and gas fire? It'd be good if people could work out heat loss off gas usage.
@@davidcoates6768 yes, I focused on my historical gas consumption a lot at the beginning of my journey. I shared it frequently in my very early videos. 👍
Slightly off topic but Octopus related so you may want to do a video on how this affects takeup of Heat Pumps. I contacted them yesterday to arrange a survey and whilst they said they could survey in the next couple of weeks the lead time for installations is currently 5 months in the Poole area !. In my case I have a very old floor standing boiler that needs replacing but I will not be able to have the heat pump benefits at all this winter. Surely if this lead time is mirrored across the other energy suppliers then given the added understanding an complexity of Heat Pump systems most people will just get a replacement combi boiler that they understand and 'trust' rather than wait 5 months for a more complex system.
Yes, this is a real issue that I have covered before and touched on in several videos. Demand is far outstripping supply, even with the significant upscaling of the big boys like octopus and British Gas etc. From what i've been told, the shortest waitlist may be with Aira.
@@UpsideDownFork Thanks for the quick reply, just done an Aira estimate and I can see why they have the shortest wait... their price for my portion of the overall cost is £3000 more than with octopus, £5900 vs £2900 !
@@3d1e00 too much air volume required. You would need a giant greenhouse and you would quickly suck every bit of warm air out of it rendering it useless as a greenhouse and as an air supply for the heat pump. Good theory, just doesn't have anywhere near the volume.
@UpsideDownFork so the compressor modifies the coolant loop pressure and mass flow to change delta and rate of temperature change to heating loop fluid? How does the fan speed come into that? Does it change too or is it a constant speed fan? Thank you for your quick replies :)
@3d1e00 this depends on the unit in question. Most modern units have a variable speed fan that seems to start at about 10% and can ramp up in small increments. The inverter driven compressors typically modulate from 30-100%. Broad statement and not speaking about the Cosy 6 specifically 👍 Your theory could/would work in certain weather conditions but in proper winter it would be useless.
I think nick accepted the risk of the buffer tank when he sited the HP a ridiculous distance from the property. If octopus wants to sick to their marketing claims they need to decline these types of implementations. He wouldn't have put a boiler out there, so why did they let him put a HP which operates an even lower flow temp? He has loads of space in the back garden and the system would likely have worked fine, even with the microbore. I also agree that all companies need smaller HPs, but more importantly more realistic heat loss calcs.
I can only really comment about my Vaillant 5kw, but over these last few days of cold straight off the not cold, I've been driven mad trying to get my system to work sensibly. It's been in a programmed time/temperature mode since installation last April, and that seemed to work well at a low cost, but that same setup has had my consumption go through the roof for these current temps - so I've literally just set mine to manual mode at 21.5 permanent to see what that does - but the point of my comment is that actually, just like with all "programmed" appliances, including cars, we've found ourselves in a situation where the hardware can be great, but it's ruined when crap programmers come along and impose their own rules via the software - with what appear to be no questions asked, and no need to explain to anyone what they've done and how the system is supposed to work.
Yes, the UI is terrible. Some of the behind the scenes programming is also questionable. I hope you are getting to grips with your Vaillant and managing to wrangle the controls. We're very very happy with ours.
Poor UI's has created an industry offering to operate your system efficiently. How bizarre is that. There can't be many purchases that a person makes where you effectively need third party entity to continually monitor and tweak it to get the best performance out of it. Just reading FB customer experiences from a variety of ASHP manufacturers, you get the sense that there is something missing from the useability of the control systems. The obvious point is that we bolt these units on to Central Heating systems in homes that each have there own unique circumstances. Differing Heat losses, varying number of radiators, underfloor heating?, 1 floor, 2 floors, north facing, south facing etc, plus actual location of ASHP in relation to the house. As I list the variables It's obvious that no unit is going to behave exactly the same at each site and that there should be enough flexibility within the control interface to allow each customer to adjust as required for their circumstances. It's clear that even where this flexibility exists within a manufactures controls, it takes some level of dedication by the end user to set it up correctly and tweak as required as the seasons change. Hence we have the companies who are based around monitoring or controlling heat pumps! - something is missing.
Long outdoor pipe runs should be avoided if possible. It states in most manufacturer manuals, around 12 meters max from pump to cylinder. Preferably most of it should be within the thermal envelope of the house. It adds up to a lot of losses in the entire lifetime of the heatpump!
I think Octopus could have done more in preparing for the launch of this. Having someone on youtube (no offence meant to you or Nick) as the initial and only source of information feels like a mistake. There's a huge amount of scrutiny on this given the media climate and their own marketing hype but they need clearer information on what this is and what it can and can't do.
MY TAKE? No experience here, just my ignorant impression from here and elsewhere. Cosy 6 is a mass production design to supply growth in heat pump demand. It is still in it's 1st iteration or so and there seems to be no doubts that the design will get refined. Like all products, this will better suit some scenarios better than others. Cosy 6 is probably best designed for older properties with older style heating & insulation standards rather than for microbore, under-floor, uber-insulated i.e not best for average newly built or recently upgraded properties. I'm expecting to buy a house with pre-80's heating architecture, so might be still suitable?
Yeah good on the guy for doing what he's doing. But from my point of view why would you site the thing so far away from the house and have all that extra pipework and potential heat loss. Surely be better to stick it on the inside of the garden wall near the house. I would be packing that trunking with insulation. Other question and this relates to my situation, The valent guy I spoke to at fully charged seemed to be quite dismissive of plastic piping. And seemed to suggest that I might need to rip all mine out in favour of putting back copper. Which I thought was odd. Surely the plastic is less of a heat conductor than copper ? Being that it gets used as Heat sinks for computers etc ? Would save me a fortune it the standard plastic is ok (I don't have microbore)
Plastic is more restrictive than copper. The outer diameter is the same but the inner diameter is reduced. So you end up with more losses. 15mm plastic pipework would be fine in most cases. It really depends on your exact home setup though and if it branches off 22mm. If you have multiple rads off a single 15mm plastic pipe then you may not be able to get enough energy through that without resorting to hydraulic separation. A buffer tank would in most cases be a lot easier, cheaper and quicker than replacing all plastic for copper.
@UpsideDownFork ah now you come to mention it yeah the inner portion of the plastic pipe is narrower that makes sense. I think the downstairs is 22 mm copper with branches off to 15 mm copper. So its just upstairs that is plastic 15 mm. So I might be ok. 1980s detached house with wall insulation. I might just replace the plastic as I refurb the second floor. As i need to rip up some crappy chipboard and replace it with 10mm ply. Cheers for the info 👍
Many houses have older people who may not have the ability of people like yourself in regards to the computer skills, they probably come to conclusion is was a bad idea to have a heat pump rather than a gas boiler replaced,
@@UpsideDownFork most people just want to have a warm home at a low running cost = that’s is = look having a heat pump will cost you less than a gas boiler = we are that confident as a industry that if it doesn’t live up to expectations then we will put your gas boiler back in .
I just turned down Octopus and went with Boxt. Hopefully I made the right decision. Boxt offered me a cheaper price with a lower design temp of 45c and upgraded the heat pump to a Vaillant 5kw. Octopus who I really wanted to go with, just put too mant obstacles in the way like structual surveys, asbestos surveys etc. This all push the price up. Octopus £3550 plus Surveys and floor prep for heat pump. Boxt, no surveys needed they did them but put disclaimers in their contract, £3700. Just to add my loft is clearly strong enough for a cylinder but i understand why they ask for it.
I am not a big fan of buffer tanks. It is more cheating than a solution in many cases. With a good heat loss calculation you can either add more/bigger radiators, UFH or add more insulation and go for a smaller heat pump.
Forget Octopus, where would the industry be without you? You’re like a national asset and certainly the reason I’m going to be getting a heat pump in a couple months.
That's really kind of you to say so! Thanks very much. I'll keep on fighting the good fight.
@ credit due where credit deserved mate. Not easy doing what you’re doing, but it’s very much appreciated.
I have watched EV Nick for years - good luck to him - whole thing looks like a lot of effort and it’s clearly important to him. Hope it runs well and efficiently soon
I'm sure they'll get there.
Like your intelligent and informed and rational user analysis of these heat pump issues. Very valuable for those like myself who are considering installation soon.
Glad it's helpful.
Given Nick's social media presence, I'm sure Octopus will be learning all the time and monitoring his system like a hawk to get the best out of it. His install is on the worst case scenario end of the scale due to the position of the pump and the primary pipe run length + microbore, so very interested to see how the performance improves following the recent changes. This install has massive publicity implications for Octopus and the Cosy 6 so I'm sure things will be put right. Octopus offer one of the cheapest installs around at the moment and there is a lot riding on the success of this install. Nick is effectively being one of the guinea pigs given he's one of the first installs and certainly the first on TH-cam that I am aware of. Nick's a great guy for sharing his install and Octopus are a trusted company, so I'm sure it will turn out right in the end.
Agreed!
@@JohnThomas-ey1hx I made a comment of his video about the length of his pipe run.
You're genuinely the only person I see calling out the REAL problems in the industry. I loved the ones on Dale Vince and the 'critiques' of Everything Electric videos. Some of these companies and people (Octopus included) gain a cult following and can do no wrong. I'm so glad you call it out when you see it.
I'm glad it is offering some value.
Useful input to the discussion. I am weighing up the possibility of replacing a boiler in a new house and matching or beating the gas cost by using a low overnight tariff and large battery to power a heat pump. More information is always good, thanks!
Glad it was helpful! Very easy to beat gas running costs with tariffs and batteries, even for inefficient heat pumps.
I’m sure Octopus Energy are learning a massive amount as they roll out their new ASHP's. They are a reputable company and I have every confidence they will get there.
@@danielbarton1694 totally agree 👍
Totally agree. Have read how they have dealt with other customers who have had issues after installs and the positive takeaway is that they do respond and work at resolving any issues which raise their head.
I know of a case where Octopus had to do a swap of a 9kw to a 6kw. It turned out that the heat loss calculation had loft insulation a zero and not 30cm.
@@bryanhindle8307 Also issues with having to design a system based upon 'MCS Calculations' (Should you want the BUS grant) which are inflexible. We were allocated the 9kw unit which would on paper be perfect for around 15 days a year, yet operate inefficiently for the other 350. Gladly our Surveyor understood this and helped us make the tweaks to get the 8kW unit allocated.
Nice to see some analysis of these real-world scenarios.
Thanks!
I've heard people say an over-sided heat pump is bad, but I've never known the reason until this video and its that the compressor can only run so low 👍
Glad you learned something new.
It's the same with gas boilers too, though doesn't have quite the same impact on efficiency as on a HP. For some reason i've got a 34kW boiler with a minimum output of 4kW and my heat loss is about 3.8kW at -3.1c so it cycles like mad.
@@SeanW-zi6kj I've been trying lower temps for my 30kW boiler, not noticed it cycling yet. Will check if theres a minimum output in the docs
according to the spec mine has a ~3kW minimum. also lists the lower 26kW and higher 35kW output versions of it and all three apparently have the same minimum 🤔
@@fairtomiddling I think they make 1 actual product then in the firmware range rate them. Happens in HPs too, the Valliant 3.5kW and 5kW are the same machine but one is firmware limited.
Vaillant does actually allow you to set a minimum flow point. Mine is set to a minimum of 22 and a max of 35 with a 0.2 heating curve.
Yes it does, but if the curve is correct and the system design is good, then those extra safety limiters are unnecessary.
@@UpsideDownFork
I use the lower limit because my smaller rooms don't really heat up if the flow temp is too low. So in autumn or early winter the flow temp needs to be a little higher, but then it doesn't need to go up much in cold weather or the room temps will overshoot. Essentially, in my house it's probably something like 25 Degrees at +10°C and 30° at -10°C or thereabouts. We only had a minimum of -13°C last winter so I don't know if my Arotherm will actually ever need to do the full 35°C.
We just had our cosy 6 commissioned yesterday. One of the engineers had fitted quite a few and said they're a lot easier to install than the daikin
How’s the cop looking in today’s cold weather?
@MCSMIK it's at 2.4 currently. I'm not sure how useful that is as it only made it to 3 degrees outside for a short time today. The cop is going up, so I'm assuming it is lower as its heating the house and water tank for the 1st time?
Thanks for checking in! Please keep us updated to date how the next week and month go for you!
@@neutron6220 presume you are running the standard 50 degrees?
@Stune5 I believe so. From what I understand, there was a bug with the app, so the data has temporarily been removed
Valiant curve can be modified on the app now
@@derekpaisley620 yes it can. I did a quick TH-cam short about that 👍
Great vid
Thank you.
Got our Cosy 6 just over a week ago. 8m primary run outside, probably 22m total. A volumiser fitted from the start as we have 10mm microbore.
SCOP so far is 3.1, which is slightly disappointing.
Octopus are sending out an engineer to check everything.
The installation team were superb.
Once we have our solar and battery in a week, the SCOP will be less important...
It has been a cold week, so don't fret too much so far.
Like you say, solar, battery and tariffs can bridge that gap easily as well!
Just a side note, SCOP is over the course of 365 days. Any other time period is referred to as COP 👍
@UpsideDownFork thanks for the reply and info, much appreciated.
Octopus fit a volumiser as standard. In Nicks case they then converted it to a buffer. It's just a case of changing pipes to it and adding a water pump.
Yep.
@@bryanhindle8307 why do they do that, do you know? It’s like £100+ of volumiser that may not be needed if you did the volume calculation for the pipework and radiators. 🤷🏻♂️
The issue is that it should be calculated beforehand. It's not hard to calculate, its what HeatGeek do (my HG did it). Sure there are border line cases where the volumiser may need to be a buffer and have a secondary pump but I think on Nicks, with microbore, its dead obvious it needs to have a buffer and higher flow temp. I think a lot of OE installs in the future will have buffers and high flow temps as it runs closer to a boiler and simplifies the install. Whether the rates OE will offer will counter the inefficiencies in that, I've no idea. There is definitely a balance to be struck on higher temps vs upgrades and better efficiency. I paid an extra £500 to have my primaries upgraded as they were borderline for running 30-35C flow temps. I could have easily designed the system to 45C and not needed to pay, but over the lifetime of that pipe work, its pretty sure to pay for itself with the savings I get and improved SCOP.
Interesting that a usual Vaillant heat curve is around 0.6. Mine's on 0.3, but the house was built in 2017.
Nice that 0.3 is keeping you warm! Is your room temp mod. set to active or inactive?
@UpsideDownFork Had a check in the settings and it's inactive.
I’ve submitted a planning application using Cosy 6… but the more I see things makes me wonder if I should ask to change to a Daikin. I have solar and battery storage. I would love a heat pump that runs at 500-800w. Seems like Cosy 6 will use way more than that and keep starting and stopping. We run our boiler at 36c most of the time and if the cosy 6 wants to run hotter… it’ll be guaranteed overheating stopping and restarting. Or any I wrong?
There's just not enough public information to make an informed decision on it.
I keep waiting and waiting for one to pop up on heatpumpmonitor!
@@MCSMIK just took a screenshot of our Cosy 6 app and we seem to be running in the low 100's of W at the moment.
Shame I can't attach them to this message...
Yes I did find it curious that Nick was offered a Cosy 6 while I have been offered a Daikin Altherma 4kW (my heat loss is I think a little more than 4kW). It might be that the form factor of the Cosy 6 wouldn't really work at my property. I didn't ask about the Cosy 6. I like that it uses a more environmentally-friendly refrigerant but I think its efficiency is a tad lower than what I should be getting, although mine is a low temperature heat pump. For me it's 10mm copper tails to the radiators and I think they tee off a backbone of 22mm copper. The surveyor mentioned a buffer tank; I'm happy with that; the space it's going into is unheated and it would be good to take the edge off that unheatedness! Anyway I've still got to get my front elevation drawing done before I can submit the planning application which is a bit of a pain but I'm dealing with it around work, selling a second house, and watching youtube videos 😂
Stop watching my videos! That's an order 😂
The daikin units are tried and tested so no worries there.
Good luck with your planning, hopefully it goes as smoothly as ours did!
The Daikin also uses R32 refrigerant, allowing it to be placed closer to doors and under windows etc, I believe the cosy 6 is R290 (propane) which has to meet more stringent criteria.
@@_Dougaldog You're right on all counts and the plan is for mine to be placed under a window; there are also air bricks around the proposed location, and all of these design constraints would have factored in.
Cool to get your take. I also follow Nick and am hoping for a heat pump in the future. Disappointing he didn't share any numbers given the title of the video. Hoping we can learn more soon
You and me both!
Not to be unduly harsh on Octopus but assuming Octopus know what they're doing and are doing a competent job is possibly not a true reflection of the situation.
We gave up with Octopus after banging my head against a wall about heat loss calculation, system design etc etc. And this is in a relatively new home that's fairly straightforward.
It seems like they can do what they can do, just a simple somewhat basic installation. Ended up going to Heat Geek. It costed more but I was happy with that with the long term view in mind.
Fair point.
I’m thinking that way too
Night and day difference between Octopus and HeatGeek. No way a HG would have installed it like that in the first place. I'm not sure if Octopus were swayed by Nick, but they/he got far too many things wrong. That long a run, with the heat demand and microbore was never going to work open circuit. Was always going to need the buffer and a second pump. He also set the flow temp far too low. The temp is what is leaving the HP, not what is arriving at the main circuit, then microbore restricting the flow meant it was never going to shed the heat it needed to. Low to mid 30's flow temp is usually reserved for UFH or for those with massive/deep rads/very low heat loss. I have a 4.5k heatloss @ -5C with UFH and can only just get away with 30-35C flow rate at design temps. Currently in negative figures outside its taking a flow temp of just over 30C to keep the house warm.
The ability to modulate to a very low power is crucial to my planned system which I will run on solar and batteries. 2kW is far too high. It is interesting that manufacturers rarely give low modulation numbers. I am looking into an Aira system - they do give modulation numbers - down to 578w for 6kW and 759w for their 8kW unit. This will work well for me. Plus, Aira make a great looking heat pump !
@@andrewbradley4261 2kw is the minimum heat output, not the electrical input.
You'll find the Vaillant Arotherm Plus 7kW modulates down to about 450W electrical input and the 7kW is approx 550W 👍
These details are rarely in the single page datasheet but are available in the full technical documents. In the case of Vaillant, that's a 295 page bible.
@@UpsideDownFork Thanks, yes - just worked this out with another heat pump. Confusing - possibly HPs should be labelled as 7-2 kW (heat) and 1.75-0.55 kW (elec.) ?
@andrewbradley4261 I agree. Labelling could be vastly improved 👍
Would have been interesting to see whether 32mm pipe or even say 42 mm pipe would have produced better results on the external run rather than a buffer tank, you get the volume of water but less resistance or turbulence in the water up to the TEEs or manifold. And why no one has designed a nice insulated tube for exterior pipes defeats me.. just off to the patent office!
Interesting points!
I think you’ll find someone has thought of the pipe. I saw something on an Artisan Electrics video covering a job at a big property with 2 very remotely located HPs. Fancy place and no expense spared. Probably why Octopus aren’t using it! 😊
@@photoman152 yep, expensive and primarily designed for underground use.
I’d love to see a comparisons of the Cosy 6 vs the Aira heat pump. They kinda offer the similar commercial approach but Aira is more of a they take responsibility long term.
Yes, I am interested in learning more about Aira and their offering. Relatively little info available online.
I have a feeling that Octopus are optimising their heat pumps differently from other manufacturers. What Octopus want is the mass adoption of heat pumps, heat efficiency is only part of that. They need something that will easily replace a gas boiler in as many homes as possible.
Higher temperature running means lower flow rates so this will work with existing pipework and easy-to-do radiator upgrades. Pipework upgrades are hard. They only need a COP greater than 2.5 because Octopus offer tariffs where electricity is about 1.5 to 2.5 times the price of gas (e.g. Cosy about 13p electric vs about 6p for gas).
Octopus want as much data as possible (including extremely detailed data from a known customer subset) so that they can plan and run better energy company and influence the grid of the future. I'm damn sure that high instrumentation with as much data as possible sent back to Octopus, is a key need.
Agreed.
Isn't the problem his microbire not allowing the high flow rates that operating at 35c would need?
@@Lewis_Standing difficult to speculate without knowing more detail but from what he's shown of his house in videos, I doubt the microbore is much of a restriction.
The cosy 6 max flow rate is 21l/m. As he has microbore and a long run, their default build for Cosy 6 is to install a hydro split and another pump to handle the central heating side.
@@derongalloway OOoo, where can I get my hands on more Cosy data like the flow rate?
Also, why does octopus use the term Hydrosplit when they install a buffer tank?
A hydrosplit would be when the outdoor unit does not have it's own circulation pump.
The Cosy 6 is a Monobloc heat pump with a circulation pump inside it which has now been hydraulically separated from the heating circuit by a buffer tank.
It seems very likely.
I think most Octopus installs have a buffer/volumiser installed as default.
Yes, volumiser on every installation.
Getting a Cosy 6 in early Jan, could not afford to go for a premium solution with BG or a Heat Geek along with the Solar and Battery install I'm getting in Dec. Boiler is 20+ years old and would be 3 grand to replace. Octopus quoted 1.8K for a Cosy 6 install with the trunking.
Everything was pointing towards going Daikin 4/6kW but I did just fancy giving this Cosy 6 a punt (when with my heart not my head), I like tech & new shiny things, I work in a technological field and happy to roll the dice that the app, features and tariff's may improve overtime just for the fun of discovery.
I'm sure you'll be fine. Octopus are just about to vacuum up a LOT of running data from existing installations as the weather turns.
They have a lot invested in this and as the biggest retail supplier of energy in the UK, they won't let it fail.
I have a Cosy 6 installation early next year and they have added a volumiser into my 3 bed semi 2000-built house. I believe the Cosy 6 has an expansion tank built into it but I wonder if the distance the buffer tank is from the house has to do with his issues?
An expansion vessel and a buffer tank serve different purposes. Try not to fall in the trap of thinking they are the same/interchangeable terms.
@ sorry should have been too separate lines, as you said you weren’t sure if the buffer tank was installed particularly for Nicks install or not.
My issue with this mass selling of heat pumps is the fact they will not design the system to be below 50 degrees flow temp, even upon request. This will affect the efficiency of the system massively, people won’t save anywhere near the money on energy they could be and the tech gets a bad name.
Just had a Viessmann 151-A fitted running at max flow temp on 40 degrees and it just sips the electricity. Coupled with the 13.5 kWh GivEnergy battery, the whole things is costing a fraction of what the gas boiler did. Happy days!
Good move!
It's a shame. Octopus did used to offer lower design flow temp upon request but it seems in their quest to speed things along that has been binned.
Biggest issue is the outside location. The designer should never have agreed to that location especially given they knew nick would be vlogging it.
Octopus put a volumiser in on all designs as default. I asked mine to be removed and they said they wouldn't.
Yes, I think Octopus really rolled the dice by agreeing to that location.
Why did you not want a volumiser?
@gmuzz
Volumiser gives a store of warm water to be pumped back into HP during defrost cycle (reduces chance of radiators cooling), there will also be a bypass valve between flow and return just after volumizer allowing sufficient flow (@ 20l/min ?) for defrost cycle should the TRVs on some or all the radiators be shut off.
In that respect it serves a different purpose than that of a buffer tank whose primary job is to allow an additional pump to be fitted on the system (pump in monoblock not enough ooomph) without the pumps fighting against each other to control flow.
At least, that's my understanding 🙃
@@UpsideDownFork its more that they haven't checked if it's needed - it's just what they do as standard.
From an engineering perspective the proposed system does not need the extra volume. It's all 15 and 22mm pipe and they're adding in 28mm for the main run. The existing rads are either too big or being upgraded.
I'm paying for something I don't need. Or in octopus's belts and braces/ cookie cutter model they are under designing and over specifying and taking more of a financial hit
I’m just getting quotes for a HP. Getting big differences in some of the specs. 🐙 are only changing a few rads which are similar to what I have but K2 (50deg flow), British Gas are quoting for massive rads for the same rads, (45deg flow) and another company are leaving all rads as they are but using a high temp HP (55deg flow). Pricing the extra rads at over £2k (rads only, the install is extra) I’m trying to justify the outlay when the amount of electric used may be minimal over a year. Any thoughts?
I could have massive unsightly rads and a huge bill (£7k after grant) but good efficiency or smaller but normal looking rads from octopus and lower efficiency - went with the latter and also had a small solar array and 10 kWh battery installed for 6k total. The battery more than makes up for the less efficiency and will be useful all year round.
Properties with a lower heat loss can comfortably get away with 50 or 55 degree flow temps with not too much worry because the overall consumption will still be low. If your properties heat loss is high, then it's definitely worth looking at lower flow temps as these upgrades could pay for themselves in a few years.
Sorry it's so variable and individual that it's hard to give specific advice but for me, I really wanted that 45 degree flow temp and was prepared to accept the rad changes that came with that.
Octopus fit the same 27l volumiser on every install, daikin or cosy.
Thanks for clarifying. 27L is pretty small for a buffer plugged into a 6kw unit.
Same 27l volumiser fitted here just over a year ago by Octopus. Daikin 8kW ashp, SCOP of 3.5, still tinkering.
@@stevept1504 27L is a fine size for a volumiser, not so great when converted for buffer tank usage.
I like that octopus would still fit the heat pump where Nick wanted, @UrbanPlumbers has recently fitted one further away than this, why loose garden space when you have that dead space with lots of airflow. Also I like how octopus monitored the system and came out to fix the system, a lot of cowboys would be a nightmare to get back if you contacted them. Have you ever looked at your past gas usage to see how many kW you used over a winter to compare to electric usage now? Or are there too many variables with hot water, hob and gas fire? It'd be good if people could work out heat loss off gas usage.
@@davidcoates6768 yes, I focused on my historical gas consumption a lot at the beginning of my journey. I shared it frequently in my very early videos. 👍
Slightly off topic but Octopus related so you may want to do a video on how this affects takeup of Heat Pumps. I contacted them yesterday to arrange a survey and whilst they said they could survey in the next couple of weeks the lead time for installations is currently 5 months in the Poole area !. In my case I have a very old floor standing boiler that needs replacing but I will not be able to have the heat pump benefits at all this winter. Surely if this lead time is mirrored across the other energy suppliers then given the added understanding an complexity of Heat Pump systems most people will just get a replacement combi boiler that they understand and 'trust' rather than wait 5 months for a more complex system.
Yes, this is a real issue that I have covered before and touched on in several videos.
Demand is far outstripping supply, even with the significant upscaling of the big boys like octopus and British Gas etc.
From what i've been told, the shortest waitlist may be with Aira.
@@UpsideDownFork Thanks for the quick reply, just done an Aira estimate and I can see why they have the shortest wait... their price for my portion of the overall cost is £3000 more than with octopus, £5900 vs £2900 !
Has anyone used a greenhouse to precondition the air for a ashp to pull from for a main house?
@@3d1e00 too much air volume required. You would need a giant greenhouse and you would quickly suck every bit of warm air out of it rendering it useless as a greenhouse and as an air supply for the heat pump.
Good theory, just doesn't have anywhere near the volume.
@UpsideDownFork so the compressor modifies the coolant loop pressure and mass flow to change delta and rate of temperature change to heating loop fluid? How does the fan speed come into that? Does it change too or is it a constant speed fan? Thank you for your quick replies :)
@3d1e00 this depends on the unit in question.
Most modern units have a variable speed fan that seems to start at about 10% and can ramp up in small increments.
The inverter driven compressors typically modulate from 30-100%.
Broad statement and not speaking about the Cosy 6 specifically 👍
Your theory could/would work in certain weather conditions but in proper winter it would be useless.
Octopus must have been mad to do an install like that. Unless they wanted to use him as Guinea Pig, but surely they would want to do it in private?
It does seem a little strange. Maybe they had the confidence and wanted to show off?
I think nick accepted the risk of the buffer tank when he sited the HP a ridiculous distance from the property. If octopus wants to sick to their marketing claims they need to decline these types of implementations. He wouldn't have put a boiler out there, so why did they let him put a HP which operates an even lower flow temp? He has loads of space in the back garden and the system would likely have worked fine, even with the microbore. I also agree that all companies need smaller HPs, but more importantly more realistic heat loss calcs.
Several good points.
I guess getting the Cosy / Octopus name out there in public is more important than the efficiency ?
What I find disappointing is I’d expect octopus to have first class software in the design side, should be a schematic of the whole system
I'd love to gain some better insights into this side of their process!
I can only really comment about my Vaillant 5kw, but over these last few days of cold straight off the not cold, I've been driven mad trying to get my system to work sensibly. It's been in a programmed time/temperature mode since installation last April, and that seemed to work well at a low cost, but that same setup has had my consumption go through the roof for these current temps - so I've literally just set mine to manual mode at 21.5 permanent to see what that does - but the point of my comment is that actually, just like with all "programmed" appliances, including cars, we've found ourselves in a situation where the hardware can be great, but it's ruined when crap programmers come along and impose their own rules via the software - with what appear to be no questions asked, and no need to explain to anyone what they've done and how the system is supposed to work.
Yes, the UI is terrible. Some of the behind the scenes programming is also questionable.
I hope you are getting to grips with your Vaillant and managing to wrangle the controls. We're very very happy with ours.
Poor UI's has created an industry offering to operate your system efficiently. How bizarre is that. There can't be many purchases that a person makes where you effectively need third party entity to continually monitor and tweak it to get the best performance out of it. Just reading FB customer experiences from a variety of ASHP manufacturers, you get the sense that there is something missing from the useability of the control systems. The obvious point is that we bolt these units on to Central Heating systems in homes that each have there own unique circumstances. Differing Heat losses, varying number of radiators, underfloor heating?, 1 floor, 2 floors, north facing, south facing etc, plus actual location of ASHP in relation to the house. As I list the variables It's obvious that no unit is going to behave exactly the same at each site and that there should be enough flexibility within the control interface to allow each customer to adjust as required for their circumstances. It's clear that even where this flexibility exists within a manufactures controls, it takes some level of dedication by the end user to set it up correctly and tweak as required as the seasons change. Hence we have the companies who are based around monitoring or controlling heat pumps! - something is missing.
Long outdoor pipe runs should be avoided if possible. It states in most manufacturer manuals, around 12 meters max from pump to cylinder. Preferably most of it should be within the thermal envelope of the house. It adds up to a lot of losses in the entire lifetime of the heatpump!
True!
Octopus have now taken away the ability to adjust the flow temperature in the app.
Yep. Owners causing too many issues apparently.
I would like you to reach out to Nick and do a visit to his house…
I'm afraid he lives too far away for me to consider an in person visit.
I think Octopus could have done more in preparing for the launch of this. Having someone on youtube (no offence meant to you or Nick) as the initial and only source of information feels like a mistake. There's a huge amount of scrutiny on this given the media climate and their own marketing hype but they need clearer information on what this is and what it can and can't do.
Agreed!
MY TAKE?
No experience here, just my ignorant impression from here and elsewhere.
Cosy 6 is a mass production design to supply growth in heat pump demand.
It is still in it's 1st iteration or so and there seems to be no doubts that the design will get refined.
Like all products, this will better suit some scenarios better than others.
Cosy 6 is probably best designed for older properties with older style heating & insulation standards rather than for microbore, under-floor, uber-insulated i.e not best for average newly built or recently upgraded properties.
I'm expecting to buy a house with pre-80's heating architecture, so might be still suitable?
Thanks for commenting!
Yeah good on the guy for doing what he's doing. But from my point of view why would you site the thing so far away from the house and have all that extra pipework and potential heat loss. Surely be better to stick it on the inside of the garden wall near the house. I would be packing that trunking with insulation. Other question and this relates to my situation, The valent guy I spoke to at fully charged seemed to be quite dismissive of plastic piping. And seemed to suggest that I might need to rip all mine out in favour of putting back copper. Which I thought was odd. Surely the plastic is less of a heat conductor than copper ? Being that it gets used as Heat sinks for computers etc ? Would save me a fortune it the standard plastic is ok (I don't have microbore)
Plastic is more restrictive than copper. The outer diameter is the same but the inner diameter is reduced. So you end up with more losses.
15mm plastic pipework would be fine in most cases. It really depends on your exact home setup though and if it branches off 22mm. If you have multiple rads off a single 15mm plastic pipe then you may not be able to get enough energy through that without resorting to hydraulic separation.
A buffer tank would in most cases be a lot easier, cheaper and quicker than replacing all plastic for copper.
@UpsideDownFork ah now you come to mention it yeah the inner portion of the plastic pipe is narrower that makes sense. I think the downstairs is 22 mm copper with branches off to 15 mm copper. So its just upstairs that is plastic 15 mm. So I might be ok. 1980s detached house with wall insulation. I might just replace the plastic as I refurb the second floor. As i need to rip up some crappy chipboard and replace it with 10mm ply. Cheers for the info 👍
@@nortonansell Sounds like your property will be a winner for a heat pump!
Many houses have older people who may not have the ability of people like yourself in regards to the computer skills, they probably come to conclusion is was a bad idea to have a heat pump rather than a gas boiler replaced,
Yes, agreed. The controllers for nearly all heat pumps are an absolute disaster. They need some serious UI work!
@@UpsideDownFork most people just want to have a warm home at a low running cost = that’s is = look having a heat pump will cost you less than a gas boiler = we are that confident as a industry that if it doesn’t live up to expectations then we will put your gas boiler back in .
I just turned down Octopus and went with Boxt. Hopefully I made the right decision. Boxt offered me a cheaper price with a lower design temp of 45c and upgraded the heat pump to a Vaillant 5kw. Octopus who I really wanted to go with, just put too mant obstacles in the way like structual surveys, asbestos surveys etc. This all push the price up. Octopus £3550 plus Surveys and floor prep for heat pump. Boxt, no surveys needed they did them but put disclaimers in their contract, £3700. Just to add my loft is clearly strong enough for a cylinder but i understand why they ask for it.
@@mackay250 that sounds good. I've not heard feedback from a boxt installation yet. Let us know how it goes 👍
@ Will do!! Bit concerned myself, but I guess that's the same with most companies?
I am not a big fan of buffer tanks. It is more cheating than a solution in many cases.
With a good heat loss calculation you can either add more/bigger radiators, UFH or add more insulation and go for a smaller heat pump.
"Cheating." Mind if I borrow that?
@ Not at all. This is just what I concluded from many Heat Geek videos and maybe someone else called it that first.
We learnt nothing as he showed no data!
He is drip feeding us and dragging it out, that's for sure, but he does give bits away every single time.
No comment this time
You're beating the system!
Oh dear, without being too derogatory Nic is a bit of dunce.
The Oxford dictionary says:
"noun
a person who is slow at learning; a stupid person."