We’re really excited to be recording a landmark Homeowners’ Q&A podcast next week:

“UK Heat Pump Heavyweights: British Gas vs Octopus Energy vs Heat Geek vs Aira vs EDF.”

We’ll be unpacking what sets these major players apart, from their installation models and consumer protections to how each maintains quality, consistency and trust at scale.

Our goal is simple: to help homeowners cut through the noise and understand where true value, reliability and long-term performance really lie.

Got a question you’d like us to ask the panel?

Drop it as a reply below, DM or email me directly at editor@renewableheatinghub.co.uk… we’ll try to include as many as we can.

@editor Here are my suggested questions:

1. In your designs, how do you trade off the up-front cost of the system versus ongoing running costs?
2. What level of efficiency (seasonal coefficient of performance - SCOP) do you design for?
3. Do you offer performance guarantees - e.g. the room temperature that can be achieved, SCOP, annual heating bills?  What recompense does the customer have, if your system doesn't meet those guarantees?
4. Under what circumstances do you recommend buffer tanks or low loss headers?  Do you warn customers that they will lower the efficiency of their systems?

@grahamf good set of questions.  Can I suggest just one minor refinement to Q1:

1. In your designs, how do you trade off the up-front cost of the system versus ongoing running costs?  Do you offer customers a choice of these trade offs?

I wanted to provide an update in regards to the insulation visit today, which may prove relevant to heat loss assessments.

He used cameras to look inside the walls and a large thermal camera to look around the property, frankly it was scary. My property is a 2004 one, however he told me that he recently did an assessment on a new built, that had the same issues as mine, with the new owners making a claim on their NHBC to get the insulation up to spec.

In my case there are huge gaps where there is no insulation between the walls, so I have cavity wall insulation randomly placed around the walls, I would estimate only around 50% coverage. In addition there are section where I could see pretty much blue on the camera. Same for the loft insulation, made it look like it was covering the loft, but with large gaps where it wouldn't be picked up.

I strongly believe that the UK has serious issues rolling out heat pumps. I don't think our houses are actually fit for them and the first step for home owners is to insulate the property as much as they can. In my case, I think I am looking at £5000+ costs.

Posted by: @drei

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I wanted to provide an update in regards to the insulation visit today, which may prove relevant to heat loss assessments.

He used cameras to look inside the walls and a large thermal camera to look around the property, frankly it was scary. My property is a 2004 one, however he told me that he recently did an assessment on a new built, that had the same issues as mine, with the new owners making a claim on their NHBC to get the insulation up to spec.

In my case there are huge gaps where there is no insulation between the walls, so I have cavity wall insulation randomly placed around the walls, I would estimate only around 50% coverage. In addition there are section where I could see pretty much blue on the camera. Same for the loft insulation, made it look like it was covering the loft, but with large gaps where it wouldn't be picked up.

I strongly believe that the UK has serious issues rolling out heat pumps. I don't think our houses are actually fit for them and the first step for home owners is to insulate the property as much as they can. In my case, I think I am looking at £5000+ costs.

Yes but...

The evidence is that many heat loss surveys overestimate the loss quite significantly, and there are relatively few reports of heat loss surveys that underestimate loss.  Your house may well be an exception, of which there will of course be many in absolute terms but likely a very small percentage.  What do we do, deconstruct every house?  I dont think so.

Unfortunately we have to deal with a legacy of dodgy builders going back centuries and as we know dodgy builders are still out there.  Thats the real world and, given that its been like that for centuries it would be an extreme optimist that thinks this may change.

We could of course conduct heat loss measurements on homes, in fact I have been advocating for over a year and a half that we do just that in the most cost effective way possible ie by using consumption as a sanity check.  Sadly few people in the industry want to hear this, because it disturbs the certainty (that they cant be blamed) that the fabric GIGO spreadsheet gives them.  And sadly few outside the industry have thought about it enough to care.

The fact is that we have to deal with the world as it is, not some idealised world that we would all love to live in.  The world as it is contains buildings that catch fire, fall down, aren't insulated in the way that they should be, have the wrong materials installed, get damp when they shouldn't and many other horrors.  So shall we stop doing anything until all that is fixed?

We need to face the fact that a proportion of the construction industry is basically sh1t, always has been and almost certainly always will be.  Then we need to deal with that whilst not paralysing ourselves.  Difficult I know, but how it is.

Of course I wish it were otherwise and I am sure you do to.!

It would explain the difference between different heat loss assessments, so the person doing it, will most likely be either accurate enough, or overestimate, which seems to be the case, better safe than sorry.

I think my heat loss assessment was pretty accurate too, taken in consideration the current insulation state. I couldn't really see any heat escaping through the outside walls, but did see some dark areas inside the house, I am not sure if it was anything to worry about. My main issue is the loft, and is something I will need to get on straight away. A few rolls of insulating loft wool should do.

When insulating lofts, how do you cover spot lights? Is there something I can put around them or just leave enough space? I was thinking like making some kind of protective shield out of mesh, so the insulation won't fall or get pushed on it. Being LEDs, they shouldn't get that hot. I think quite a bit of heat is escaping around the spot lights, maybe there is some sort of rubber seal that you can put around them.

Posted by: @drei

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When insulating lofts, how do you cover spot lights?

try these

https://www.screwfix.com/p/loftleg-loft-lid-downlight-protector-155mm/327TL?gclsrc=aw.ds&gad_source=1&gad_campaignid=22599672207&gbraid=0AAAAAD8IdPzRai6jeP0sEQ7zYseYkSeYH&gclid=Cj0KCQjw35bIBhDqARIsAGjd-cafi3kFb4MtJp9KdpyN-ZkRr7FcwWOVYRcnG5IEaliQ6p1gvwgqlX8aAt8-EALw_wcB  

Posted by: @drei

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It would explain the difference between different heat loss assessments, so the person doing it, will most likely be either accurate enough, or overestimate, which seems to be the case, better safe than sorry.

Very definitely.

I think the market has changed a bit since mine were first done now nearly three years ago.  There are clearly loads of installers out there who still religiously use the default assumptions, dialled into opaque tools, which can lead to large overestimates that have a material effect on the design - eg 16kW 'surveyed' vs 7kW actual in my case.  The same installers will often refuse to account for invisible fabric upgrades, like IWI for example.  There is also another class of installers who use experience more, often with much simpler (and thus much more transparent and if necessary flexible) spreadsheets/tools, to arrive at figures which are usually more realistic, but much more dependent on installer skill.  The most recent podcast about the heat geek 'zero disrupt' offer refers to this obliquely but quite extensively.  

The two which I eventually shortlisted for my install fell firmly into the latter category.  Simple tools (bordering on crude) combined with experience and (hopefully) bolstered by my own consumption data, leading them to propose 7kW designs rather than 'safe' (for them not the customer) 16kW designs.  Perhaps they have made mistakes along the way, but have learned from them. 

I can accept installers making mistakes, we all do from time to time and we all have to start somewhere with our learning processes.  What I cant accept is installers who ignore solid evidence that what they are proposing is wrong or who, having made mistakes, resist fixing them! 

Posted by: @jords

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One thing that surprised me the most was the differences in heat loss between the three. Heat Geek and British Gas used LiDAR on an iPad. Octopus did it the old fashioned way with a laser tape measure and app.

	Heat Geek	Octopus	British Gas
Kitchen	2280	2223	2233
Playroom	550	667	533
WC	160	185	105
Living Room	1530	2004	1938
Entrance Hall	300		487
Shower Room	650	1167	705
Landing	190	166
Bedroom 3	360	346	473
Bathroom	360	630	408
Bedroom 2	450	371	530
Bedroom 1	660	674	873
Loft Landing	320	565	484
Office / Bedroom 4	640	869	934

Same rooms are very similar. Others very different. They also all chose different outside design temps. Heat Geek: -2, Octopus: -2.4, British Gas: -2.9

Radiator changes. Heat Geek: 4, Octopus: 8, British Gas: 10 plus a plinth heater for the kitchen.

Anyway just thought I would share my experience with the 3. Maybe I’m being too picky. But if I’m going to spent £10k (after the bus grant) I would like to make sure it’s just right.

Thank you, this is very useful. We are just about to embark in the survey stage. 

I am wondering whether installers are able to reuse the surveys others did (as they are presumably all aiming to apply the same MCS "best practice") 

Posted by: @batpred

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I am wondering whether installers are able to reuse the surveys others did (as they are presumably all aiming to apply the same MCS "best practice") 

In my experience no!

I think the figures show the extent to which heat loss surveys are what-iffery, all depending on the assumptions you (or rather they) make.  Thats why I always advise sense checking against a measured figure for the total if the information is available.  The variation in individual room performance shows why you should balance for room temperature not equal deltaT, although in practice rooms share heat a lot so this is somewhat smeared out.

@jamespa There is also the ‘blame factor’, if one installer were to use another’s heat loss calculations, they would have a reinforced concrete excuse were the results ‘disappointing’ imagine the litigation! Regards, Toodles.

Posted by: @toodles

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@jamespa There is also the ‘blame factor’, if one installer were to use another’s heat loss calculations, they would have a reinforced concrete excuse were the results ‘disappointing’ imagine the litigation! Regards, Toodles.

On the litigation, I would not go there and definitely not around heat loss calculations. It would be straight to the installer, of course. 

Anyway, the cynic in me says that as is usually a chargeable service, they have no incentive to miss out. 🙂