@ksim, I agree with you that HG has essentially evolved into a software-led company trying to solve a systemic problem and the UK probably does need better design tooling, better standardisation and fewer installs that rely on “that’ll probably be fine” as a design principle.

Where things get uncomfortable, and where I think the podcast ‘friction’ came from, is that software confidence doesn’t always translate cleanly into real-world pricing or homeowner outcomes. The messaging leans hard into “less disruption, lower cost, faster installs”, but the lived experience for some homeowners (including yours) doesn’t always line up with that promise once you get past the headline numbers. When someone arrives expecting a £2-4k marginal upgrade and instead lands on a £7.5k “that’s just what heat pumps cost” conversation, that gap is important.

Your example is especially interesting because you’re not a typical homeowner wandering in blind. You know your heat loss, you know your flows, you know how your house behaves thermally, and you went into the process expecting the software and survey to reduce scope, not inflate it. From a technical perspective, your logic is sound. If anything, your case is exactly the sort of property Zero Disrupt is supposed to excel in. Yet even there, the final number snapped back to the gravitational pull of “normal heat pump pricing”. 

That’s the bit I keep circling back to. We now have two universes forming in the heat pump world. On one side, the big, software-led, volume-driven players trying to compress time, cost and friction. On the other, smaller installers who design deeply, move slowly, charge more and often have long lead times. ZeroDisrupt is clearly trying to bridge that gap, but in practice it’s still constrained by installer economics, risk, warranty and the simple fact that turning theory into a working system in a real house still requires skilled humans on site for multiple days.

None of that makes ZD pointless. As you say, it’s a tool. But tools don’t set prices, installers do. And until the cost structure of installs genuinely changes, there’s a risk that ZeroDisrupt becomes more of a framing device than a price revolution. For homeowners like your friend, or like you, the danger is that they get close enough to the idea of a heat pump to be intrigued, but still bounce back to a boiler when the final number lands because it’s not going to be as cheap as initially communicated to them.

I’ll give them the benefit of the doubt and say it’s not done in bad faith or hype for the sake of it. I think it’s about a collision between ambition, software capability and the messy reality of retrofit installations.

@editor You are absolutely right in pricing, but it is not software inflated the price, it is the installer inflated price, he has plenty of work coming his way and not enough competition to drop prices.

You know your heat loss, you know your flows,

I would love not to be, and the reason I learned that is not heat pumps. I was born in a country where heating is designed for -35C, with 50C flows, because no one want their child getting burns if they touch a radiator, radiators are aluminium, built by section, last forever, pipes are plastic. And no one talks about heating, it just works, if it doesn't you call a plumber, and they fix it really cheap. Gas is dirt cheap, so, sadly, nobody cares about HP either.

When I moved into the UK, first, oh, how cold it is, ok rented property, old back boiler, just accept and pay. Bought a house, 3  years old renovation, UFH, new condensing boiler, and even worse; wife complains it constantly cold, condensation... So I had to learn heating, was not even thinking about heat pumps at that time. My boiler setup was: 2 zones with 2 different thermostats in strange places, flow 80C, unbalanced rads, massively oversized boiler (25kW vs 3kW loss), at 80C flow the boiler was overheating the small zones go into anti-cycling, resulting no heat and massive gas usage. I removed all zoning, balanced radiators, set the boiler on the lowest power, written custom controller first on load compensation and next weather compensation. now boiler runs sub 45C flows, never goes into anti-cycling, the house is at constant comfortable temperature. My has usage dropped from ~9500kWh to ~6100 kWh with 0 complains from my wife. 

Why I mention this? simple, People just live with bad boilers installs, nobody says gas boilers are bad, do not work in the UK climate, just complain that energy bill is high and asking for government to subsidise cost of their inefficient systems; I walk in my town and see "clouds manufacturing" with people "heating" outside of their houses, with my boiler  you can't see vapour until it is freezing and even it is freezing it barely noticeable. With Heat pumps people blame HP immediately. The problem is not HP or boiler, the problem is installers. I have no doubt professional experienced installer which will crawl through every inch of the house can do more efficient than approximating and averaging software, those installers are rare and expensive. So HG ZD might not match the top 1% of the installers, but it is better than 90% of gas and HP installers we have right now. So far only HG made the system proposal to the level I think it is reasonable, the rest is specifying 9-10kW Heat pumps with buffers and low loss headers. I got a quote for 9kW system+cylinder with buffer for £2700, which is reasonable in price and I would pay that, but proposed configuration will cost me 50-100% of efficiency.

I do not think retrofit is messy, or heat pumps that complex, it is just quality of training, outdated guidelines, and low quantity manufactures making misleading recommendations with their heat pump. I had one of the Grant UK HP installers, on your youtube channel Neil Sawers says buffers are killing the efficiency and they do not recommend buffers, but the installer come and says it is Grant who says to fit low loss headers and volumisers, as if there is any problem with warranty the installer will be in trouble for not fitting one. His words not mine.... 

As another example, just got off the call with a partner of EDF Heat pumps, they (26 years of experience fitting heat pumps from their words) wouldn't fit a heat pump to my house,  because: and let me quote: "microbore is too restrictive, by the time water get to the radiator it looses temperature". I would love the guy just to have the software tell him what to do instead of doing taking himself; went to their website, buffers, separation all the way. But we agreed that I have a magic boiler which somehow heats the house with flows sub 45C, but in reality it is not possible... 

@ksim Mathematicians have calculated that bees can’t fly - but fortunately, no-one has told the bees! 🤨 Toodles.

Posted by: @ksim

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As another example, just got off the call with a partner of EDF Heat pumps, they (26 years of experience fitting heat pumps from their words) wouldn't fit a heat pump to my house,  because: and let me quote: "microbore is too restrictive, by the time water get to the radiator it looses temperature".

The thing that worries me is that this brainless crap is only going to get worse as AI reinforces AI trained by brainless crap like this.

Physically humans are not, by a very long way, the apex predator.  We currently occupy the apex position because of our ability to think and to share our thoughts with other humans. 

That ability was already set to decline starting 20-30 years ago when it became obvious that, broad brush, the more intelligent people were having fewer offspring than the less intelligent people (no causality or comment intended, just fact at least in Western Europe).  This is possible (from a genetic point of view) because the benefits of modern society result in a decline in the genetic advantage of intelligence (and indeed of physical strength).

With the advent of AI the evolutionary advantage of intelligence will be further eroded.  The reproductive/survival advantage will lie solely with those who are ruthless or whose parents own the AI, until such time as the humans with physical strength decide that enough is enough, and create a bloody revolution.  Alternatively much of the human race will be consumed from its boundaries by physically strong creatures (or less strong but equally potent forces such as a virus or bacterium) which those who own the AI no longer need fend off because they no longer need the rest of humanity.

Not a nice thought, but well worth deep contemplation before making voting choices! 

• Think values not promises,
• think about whether promises are realistic - all politicians make promises, some of which are unrealistic, because thats the only way WE (the public) allow them to win elections,
• think about whether what you read in the media is a true reflection of truth or a virtual reality heavily influenced by the self interest of those who control it
• think beyond yourself,
• think about direction of travel and what it leads ultimately to,
• think about your children and grandchildren and think about irresistible exterior forces. 
• Also when you choose the cheapest, think about if that is really what you want (do you, for example, value customer service?

Above all THINK, because that is the only reason homo sapiens currently enjoys its favoured position.  

Posted by: @toodles

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@ksim Mathematicians have calculated that bees can’t fly - but fortunately, no-one has told the bees! 🤨 Toodles.

I'm a hobbyist beekeeper with a few colonies in the back garden, the education for which was initially self-taught via YouTube videos and books during Covid lockdown.

There's a vast amount of well documented, accumulated knowledge driving what gets taught on modern beekeeping courses, but it doesn't take too long when managing colonies to encounter a situation where the well used comment of "the bees don't read the textbooks" becomes a reality.

Posted by: @sheriff-fatman

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…

but it doesn't take too long when managing colonies to encounter a situation where the well used comment of "the bees don't read the textbooks" becomes a reality.

…otherwise known as “hive got news for you”.

And don’t bother; my taxi’s already ordered.

@majordennisbloodnok And did ‘Honey’ order it for you? Toodles.

@editor how about a video "ChatGPT vs average heating engineer". 🤣  

So I did an experiment and asked ChatGPT for HP size recommendation and would it recommend hydraulic separation like low-loss header or buffer, fed to it all numbers from by gas consumption and boiler data flow temps data. this is the result:

Almost the same question for Gemini:

Final was Claude:

I can experiment with feeding to it the heat loss calculation, but decided to make it fairer as not all installers I've contacted were able to do it, basically everyone had the same or even more data, so I would say LLMs are better than 90% of boiler and heat pump installers out there.

@ksim, I don’t actually disagree with much of what you’ve said... in fact, your boiler example is a perfect illustration of the real problem. Most people live for years with badly designed heating systems, whether gas or heat pump, because the system kind of works and no one ever joins the dots between comfort, efficiency and design. High bills get normalised. Poor installs get tolerated. At the end of the day, boilers are forgiving. 

Where I’d push back slightly is on where the system failure sits in the UK. Yes, installers inflate prices when demand outstrips supply... that’s basic economics. But that market distortion has been turbo-charged by a scheme that doesn’t properly enforce design quality. If you can self-certify a system, issue a certificate, unlock public money and never have to submit or defend your heat loss, emitter design or hydraulic logic, then the installer incentive is skewed toward speed, not excellence.

Your experience shows exactly why this is important. You understood the heat loss, reduced flow temperatures, removed pointless zoning and suddenly the system worked properly. Most homeowners never get that opportunity because the design decisions are opaque and unchallengeable. When the result is poor, the paperwork still says everything is “compliant”. That’s the difference between living with a bad gas boiler quietly and a heat pump being publicly blamed... heat pumps are sold on performance, so when performance falls short, the technology takes the hit.

On software, I’m not arguing that it beats the top 1% of installers who will crawl every inch of a house. I agree with you... those people exist, they’re excellent and they’re rare. My concern is that the floor is too low. If software-led design can reliably outperform 70-90% of current installs, then that tells us how broken the baseline is, not that the software is the problem. There are a lot of incompetent installers out there.

Buffers, low loss headers and volumisers are a great example of this mess too. One part of the industry publicly acknowledges they damage efficiency, while another hides behind “manufacturer guidance” to protect warranty and liability (which is garbage). The homeowner ends up paying for the inefficiency, in running costs and reputation damage to heat pumps as a whole.

So yes, the core problem is installer quality. But systems like MCS exist because we cannot rely on every install being done by the top 1%. If the scheme doesn’t enforce competence, evidence and outcomes, then it rewards mediocrity while the technology takes the blame. And that’s where things have gone badly wrong, because MCS in its current form is not fit for purpose.

Posted by: @ksim

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@editor how about a video "ChatGPT vs average heating engineer".  

I'll be honest, I love that idea! I'll start working on that later this week. "Average" heating engineer vs ChatGPT vs Wattson... 

@ksim, this document (Heat Pump Suitability Assessment & Recommendation) what is the information modelled on? Is it your property or a hypothetical one?

@editor It is based on my property, I described my heating system open loop + UFH + radiators on 8mm microbore, indoor temperatures, current Gas boiler delta T, boiler power and for how long it is running every hour, + annual gas consumption. asked to calculate required flows because of microbore. My gas boiler data is deeper than many houses have, but installers had access to it also, so I think it is fair. I can also compare the results with what I was told by different surveyors and installers about exactly the same property.

Happy to provide prompt I've used, all used models are reasoning, which also very interesting to read, for example Gemini calculates that the flow should be fine, but still scared of microbore so recommends buffer tank. I didn't spent any time optimising the prompts. It would be interesting maybe experiment with longer chats, but my experiment was simple prompt -> response,  low effort ;-).