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A very bias panel of people in this discussion that seam to single out certain business yet there are hundreds of company's large and small that are installing buffers for one reason or another, yet you assume they are bad installs! has any one you reached out to these bigger company's to find out why they are using the installation type they are ? as for this constant comparison of SCOP's there are hundreds of reasons why a SCOP could be low. Poor insulation, old windows etc and not always due to buffers. All these types of discussions are causing is more customer uncertainty. Why not show some positivity to what some of these company's are doing like enabling customers with any financial backing the chance to have a heat pump. lower tariffs and helping turn the industry from gas to renewables.

A great scop on an open loop system is great for the vain plumbers. My hp is switched on and off to make me comfortable. It costs a lot less to run than leaving it on all the time. BUT my scop is a bit less Scop is a vanity project

Production critique: please ask the folks with laptops to stop banging the table the laptop is sitting on. Their jiggling cameras are giving me a headache. The guy in the top left and top right keep doing it and it's not great.

Most installers won't omit a Buffer from their system......what then?

Wow, so dangerous, yes heat pumps are inverter driven and hence output is variable, radiator/emmitor demand is variable, the two however are rarely equal, this is why you're promoting an "open loop". No discussion on compressor wear when buffer vessels are not installed. If you want a heating system you can control and one you can rely on use a buffer, use zone control on your heating. Decoupling your heat pump fro. Your home is one of the most critical aspects, what is being promoted here is saving cost on a buffer and piping to enable volume install.

Excellent discussion… so glad I removed our buffer tank. We needed to learn about energy carrying capacity of a few short runs of microbore within the existing few rads but everything now runs effectively down to 35c LWT using one circ. pump. Installer agreed to make changes FOC. (4 bed house, 8.5 ecodan, 15 rads twin coil 250L unvented tank.) cop 3.8 to 4.2 but possibly up to 18% underestimated efficiency as MELCloud sourced info. Perhaps manufacturers need to review and improve their own brand performance reporting as they are probably inadvertently damaging their own brand!

This video had the potential to spark a great debate on heat pump system design. Unfortunately it was the equivalent of Question Time with a panel of MP’s from the same party…… Maybe next time do it with Brendon and Ken Bone, Paul Spence, a manufacturer and maybe a Heat geek…….now that would make for a much more diverse conversation. 🤣

Thoroughly enjoyed this, thanks for the informative discussion

Excellent

Homely (an AI system to manage the heat pump) doesn’t work with a buffer tank. It needs the flow and return temperatures to accurately determine the efficiency of the system and the buffer tank disrupts its algorithms. Once we got written confirmation from Homely, and agreement from Midea that removing the buffer tank wouldn’t affect the warranty, the installer removed the buffer tank . COP then improved.

I think you should have invited HeatGeeks or UrbanPlumbers 👍

Sure, in new systems, there's no excuse for using any unnecessary components but, buffers shouldn't become extinct. There are always going to be outlying cases in retrofits where it's possibly the only realistic option. I thought Simon was going to touch on this at one point, when he started talking about and pressure loss. How would he deal with microbore embedded in walls when the pressure drop of the index circuit it too great for the ASHP's internal pump? There are plenty of 70's and 80's properties where re-piping the whole place is just not a realistic option. Even more recent properties with plastic microbore. What if the customer doesn't want their property ripped apart because "it will be more efficient". Spend a bit extra each year on your heating bill, or spend thousands extra getting half the property re-piped and redecorated.

HI guys great content, very useful I am in the buying process at the moment. Do I need a buffer tank if I have a cascade system 2 x 10 KWh . Also I have a large house 300 Square meters. If a 18 KWh AHP could work would this be better than 2 x or 9 KWH..

I can store energy in the accumulation tank when the kwh price is cheaper or when there is a lot of solar energy. The thing is that you need a shunt motor valve to regulate your heating curve. And a regulator connected to octopus say to the heatpump when to produce heat.

Everyone i know with one , complains about noise. So do there neighbours. Its enough for me to think against it.

The greatest thing since sliced bread last week.They have that many excuses don’t they I can bring another guy that says micro bore.Designed they just rammed mine in disconnected my Combi and have put two different heat pumps in and ran away.First one DearDear swooped it for another one and Dear Dearer haha I kid you not.All fitted from start to finish by MCS accredited so called TRADESMEN MCS waste of time.

Noticed you have the legs installed inward as opposed to the suggested outward

You gotta love the process.

Hilarious 🤣🤣🤣

Brilliant, brilliant, brilliant...

when the seller sells, then everything fits

Very loud

So noisy, should be banned! 😂😂

Exactly the sort of humorous take people need to understand. Congrats

MCS offers no assurance to Consumers in reality when things go wrong. If a company should cease trading and you contact them for help, they are not interested and send you on a merry -go round. Eventually you'll be asked if you paid by credit card and suggest you contact them. Seriously, they are not fit for purpose.

It's not the noise level that's the problem it's the low mind boring hum that drives us crazy. I have a neighbour either side that has fitted heat pumps and what was a nice quiet neighbourhood is now a droning hum factory that keeps us all awake at night.I get really annoyed at videos like this defending them by showing the db level - that's not the point it's the ghastly HUMMMMMMMMMMMMMMMMMMMM 24hrs a day that's the issue so stop trying to justify these monstrous things by measuring db levels.

This is my life! Oh dear 😂

Womp Womp

Hehe. I know a guy like that.

sounds just like my husband LOL

very funny, if you know you know LOL

But your wall temperature is different from your room temperature 🤔

This is a very informative and as such presents a scary picture of how heat pumps will / will not replace other forms of heating especially in older/larger properties. From your account of the installation you have retained microbore pipework and not enlarged the radiators as I can imagine they would be totally unacceptable from an aesthetic point of view. I dread to think how much your current system cost and how much more to try to make it satisfactory. I think you will be faced with having to install a conventional boiler to run in parallel with the HP to give you the room temperature needed especially on cold windy days. I await the next 'instalment' with considerable scepticism.

The fact is that while modern heat pumps are better than the on/off version of old their modulation is still limited so sizing a heat pump to work over a wide ambient temperature range is non-trivial. If you want a heat pump to run at it's quietest most of the time then chances are it will be oversized for more moderate ambient temperatures. The buffer is required for these more moderate temperatures. The key to higher (S)COP in modern systems is weather/temperature compensation. Put bluntly this means moving less heat at higher ambient temperatures. The irony is higher temperatures also have massively higher COP. This explains why a buffer is needed. A heat pump with COP of 3 at 0oC may have a COP of 6 to 7 at 15oC while the minimum input power will be unchanged. The fact is the manufacturers go to some length to be opaque about their minimum input/output figures and modulation range. It's all about maximum output when we really need to know both max and min across the operating temperature range. If you and your neighbors are OK with your heat pump running at 100% on cold days making a racket then go ahead and don't bother with a buffer. Also remember the COP is dependent on load. 100% load has lower COP than 25% load. The reason why buffers are said to lower the COP is because (1) an extra pump is required similar to a low-loss header (2) heating the additional water in an on/off thermostat driven system takes more energy than to heat just the volume of the heating circuits. However, the heat in this case is "buffered" so the loss is neglible, assuming the heat pump is not running at 100% to heat the extra volume (hint: quiet mode is your friend). In a system modulated on leaving water temperature (LWT) alone the buffer makes no difference compared to the low loss header and for low temperature systems may make a lot of sense. The buffer is therefore daemonized on forums like this. Primarily it's the additional 30W or so drawn by the pump which reduces the COP, albeit to make a more comfortable climate. There are trade-offs to be made and sometimes a reduction of COP is a price worth paying for a more positive experience in comfort and lowest power consumption. I can still get a COP of 4.2 with a 200 litre buffer. This is fine for me. Chasing COP alone is a fools errand. Looking at heatpumpmonitor.org stats there are systems definitely running buffers with even higher COPs so I am struggling to see the problem. There are small output systems not running buffers which run continuously, have very high COP but consume more power. I recommend adding the elec consumption column to see this. The objective is to minimize power consumption and maximize comfort. In large houses with complex heat loss distributions, large thermal mass, low temperature hydronic heating and multiple zones the buffer makes sense. In small houses with uniform losses, low thermal mass, highish temperature radiators, a single zone and simple controls it does not. Ultimately the buffer increases the thermal mass of the system. If I was to say I have no buffer but a concrete basement with underfloor heating with a high thermal mass and no low loss header that would apparently be acceptable because there would be no additional pump. This is a silly argument. In hydronic heating systems small variations in LWT can be really uncomfortable. If the heat pump cannot follow its weather dependent curve and goes say 4oC over the target temperature it can make a pure flow base system horrid to live with. When combined with a mixing valve the LWT from the buffer is far more controlled. As always on the internet, treat anything you read, including this, with caution. What folks should ask is what size heat pump is required for their house and what size buffer would fit with such an installation. It's pure physics. The best investment any heat pump owner can make is in a monitoring system such as emonhp or an esp32. Heat pumps have many configurable variables and need to be carefully optimized post-installation. As a technology the heat pump will ultimately fail if the optimization is not made more straight forward. There is a disconnect between the expectation of the customer and the reality of ownership. The vendors don't help by having limited data access to their systems to allow straightforward assessement of the performance of the system. Blaming all ills on the buffer tank is a massive over simplification of an industry in denial. These are not turnkey systems. Stop treating them like they are. The referenced article renewableheatinghub.co.uk/how-to-correctly-install-heat-pumps-so-that-they-work-properly-and-efficiently is questionable as the data simply illustrates that COP is higher for lower average LWT modulating at a single temperature of 7oC. I agree the 4-pipe buffer with mixing requires marginally higher temperature, as the LWT will be the average temperature (-2.5oC lower than heat pump LWT) although this can be mitigated to a degree through the use of the 3-pipe design. All heat pumps will have to stop start at some point given the limited modulation range at higher ambient temperature. e.g. there is no comparison at 0oC, 2oC, 12oC and 15oC. The challenge is how to limit the vampire power draw of pumps when the compressor is not running, particularly at higher ambient temperature. What is demonstrated here is the observation exercise has to be performed for every installation - minimum LWT to achieve the desired room temperature. Otherwise I agree with the conclusions of the article about the industry as a whole.

Ken knows his stuff for sure. You can rest easy once he is onboard.

We have had our heat pump (Samsung 16kw) for 9 years now and it is only in the last 2 years that I have understood how to get it working efficiently. Our installers did some things very badly and some not so badly. Firstly, for a 16kw heat pump, we should have had 35mm primary pipework, but we were given 28mm. As it turns out, this is not so bad, as our heat pump is massively over-sized and we don't actually need to deliver 16kw of heat, so the pipework is adequate. We already had mainly 22mm central heating pipes, going down to 15mm on the short runs to each radiator, so this is fine. The second bad thing they did was to give us 5 different zones, when actually we only need two, one for our cellars and one for the upper 2 floors of the house. The third bad thing was that they configured the heat pump to run at a constant 45c flow temp, when it should have been on weather compensation. For the first 7 years it cost us roughly double what it should have done to run, had an average SCOP of about 2.0 and our house wasn't as evenly warm as I would have liked it. HOWEVER, 2 years ago I took it upon myself to learn everything I could about our system and heat pumps in general. It turns out that our install is not actually that bad and that when configured correctly, our heat pump can run efficiently and can keep our house at a lovely, warm and even temperature. We don't have a buffer (that was a good thing on the part of the installers, as were the 3 panel radiators they installed), we now have it running on weather comp, with a max flow temp of 38c and a minimum of 27c. We leave it on 24/7, with a 2c setback at night. We have reduced the flow rate to hit an average of between 5c and 6c Delta T. We have reduced the flow to the UFH loops in the cellar and have made this open zone instead of 4 different zones. We have balanced the flow to all radiators and to the UFH loops so that we get an even radiator temp for all rads and an even indoor temp in all rooms. The net result is that our SCOP is now averaging 4.0 and our house is much warmer. Our heat pump costs half of what our modern condensing gas boiler does to heat our house, on Octopus Agile tariff (we have a hybrid system, so can use the heat pump or the gas boiler and can accurately measure costs for both). Heat pump performance is all about two things: quality of installation and quality of configuration.

This is a very interesting video and exposes two of my main concerns regarding ASHP suitability in our house: 1) We have a fairly large old house but we have hydronic underfloor heating (two circuits, two pumps, sixteen zones and 14 thermostats), a thermal store and an oil boiler. The system was installed by the previous owner so is something like 20 years old (although the boiler is much newer). The house is pretty warm in all of the heated rooms but it does cost a bit to run. Were we to have to change our boiler for a heat pump based system, I would have nightmares about the possible upheaval and cost if floors needed to be ripped up and underfloor heating replaced. 2) So many installation companies seem to be jumping on the renewables band wagon but not applying modern heat pump principles and common sense to design and build. As this video demonstrates, gas and oil boiler based design doesn't necessarily apply to heat pumps. It seems like an affiliated company to something like Heat Geeks is the safest way to go because there is a chance that the designer of the system has passed the course and is applying the content rather than guessing and using old theories. I typed our address into the Heat Geek site and the algorithm claimed that our house wasn't suitable for a heat pump because it is too large and too inefficient! Hmmm ! Our boiler is running fine at the moment and we will continue with it. Hopefully, as the months and years tick by, the industry will become more knowledgeable with regard to designing heat pumps into old housing stock and more installers who have a clue will be available. For now though, it still seems like a bit of a lottery finding a decent installer. The chap in the video seems to be talking complete sense, as far as I can tell. Hold on to him!

Top man is our Ken. Sadly this type of install is far too common, chuck a heat pump in and dont do any design inside thouse. If you are getting quotes heat loss and internal design and commission is needed as part of the qutation. Im a tech support engineer for Stiebel Eltron and we can help with all this side.

Hi Mars - having followed your heat pump story from the beginning I am pleased to see this video and that you having an independent ‘root and branch’ review of your system. It would be really useful if your heating engineer could construct a ‘block diagram’ of the current system showing the DTs and flow rates at the key nodes in the system (he will have to do this for himself anyway to analyse what he is dealing with here) and of course when he makes changes for an amended diagram with DTs and flow rates - to illustrate the follow-up video. Are you going to take the opportunity to fit openenergy monitoring equipment? Best wishes.

Ken is a real heat pump pro with his own RUclips channel and I've heard other top heat pumps engineers reference his work positively. If Ken can't do it nobody can!

I'm glad you got one of the best in to fix the problem.

I would say having listened to Ken, he seems to know what he's talking about. In my experiance - I'm not a CH expert, but I do most of my plumbing myself - I can say it's more about the confidence in right sizing the radiators and the heat loss for the size of rooms, as well as ensuring has Ken stated, that the pipe size installed is capable of being able to transfer the correct amount of energy into those radiators in order to warm the rooms sufficiently. I didn't have enough confidence when sizing my boiler to pick one that was smaller than I choose, hence my system is still overpowered, and even though I'm running the boiler at lower temperatures to achieve high output, my radiators are really sized for 60 degrees C minimum when I should maybe have chosen larger ones. Ideally I would like to transition to under floor heating, but retrofitting this is not ever going to be a reality with solid concrete floors downstairs, even though I would also benefit by installing insulation in my 1980's built house..... I just can't imagine the mess! In the old days boilers were installed by 'engineers' who used rule of thumb to guess how much energy a property required - and it didn't matter much as the boilers oftern ran flat out with water temperatures up to or enev above 80 degrees C. Boilers were often oversized - so they short cycled, and efficiencies were not considered. Converting such old systems to run with heat pumps is a complete minefield, and they mostly will not run efficiently at low temperatures as there will be insuffficient energy within the water in the system and again as Ken said the flow rate has to be increased drastically to try and make up for this difference, with the old rad's changed out for much larger more efficient radiators, to try and extract the max energy from the flow.... However if the pipe size is too restrictive, you can't get the correct flow rates! www.youtube.com/@UrbanPlumbers also seems to know what he's talking about and is often saying there is too much control taking place even in new installations. This one in particular may apply to you: ruclips.net/video/AXamAjE0juw/видео.html. When assuming you can achieve sufficient flow rates, and the radiators are right sized for the flow temperature, then balancing the system can often lead to high COP and even temperatures thoughout. Especially with underfloor heating, Mixing valves are not desirable or necessary with flow temperatures of 55 degrees or less, instead making sure the correct flow rate per loop is achieved to result in the correct amount of energy/loop being realised. This ensures the water temperature flowing back to the heat source is also optimised, and hence the source is able to pump the correct amount of energy back into the system without throttling down it's output. I wish you and Ken good luck with sorting out all the problems. Maybe being an older property it's possible to re-engineer some of the pipework under the floor - I crawled under my parents floor as a kid doing pipework for my dad, so dependant upon access and trhe height of the joists.... who knows. P.S. I'm 64 now, so probably wouldn't fit anymore and wouldn't want to do that sort of thing in any case!

Hi Mars. Sorry your ASHP not working out as you hoped. I’ve followed your discussions and selection and installation progress. You interviewed me on your channel about my ASHP. And I continue to post my ASHP SCOP and running costs on your Renewable Heating Hub information site. So I’m slightly surprised by your system revelations. I don’t know the chap discussing your installation having undertaken a review. He sounds sensible and knowledgeable. But please seek alternative views. That’s my top tip. Given your knowledge and experience (perhaps it came after your installation) I was wondering why you didn’t enquire about all your system components? Numbers of pumps. Valves. Controls on controls. Good luck with the investigations. What about the original installers? Why did they make it so complex? There are definitely two schools of ASHP: ones who fit buffer tanks and those that don’t.

Great Noise Collection 😵‍💫

My friend has a next door neighbour with one - and those continual noise is driving the neighbours crazy - it’s like living next to a fish and chip shop - with an extractor fan

Listening to that all bloody day will drive me nuts - I live in a lovely quiet road and my neighbour is having one fitted today - from listening to all the videos I’m dreading it - that continual humming is so annoying - and we have windows open in the winter at night - it’s going to be bloody awful - these stupid machines should fr banned

Hi Mars, some thermostats use resistors above the temperature sensor to generate a small bit of heat in order to create sufficient convection currents to let the ambient room air flow through it at a reasonable rate. (in theory) This is designed not to affect the measurement much at all, but should provide a more accurate measurement of the environment.

Great installation. Like the Viessmann colour control screen

Great explanation, really interesting underground plant room, wish more house developers added this

An excellent piece of guidance. I've also found that mine can drift periodically, so worth rechecking them from time to.time