Not sure if this has already been posted and I haven't read the report. Just posting in case anyone wants to read 

https://www.pv-magazine.com/2026/04/17/thermostatic-radiator-valves-can-reduce-energy-consumption-in-air-source-heat-pumps-by-6-8/

The original paper is 84 pages long so deserves a good read, which I intend to do.

The key question, which is not stated in the summary, is 'what is the control' ( in the sense of what is the comparison relative to).  Without understanding that, which will require reading the paper, the summary is totally meaningless.

A quick skim suggests that the TRVs reduced room at least some room temperatures in which case the control may be s poorly balanced system or one where the WC was poorly adjusted.  If so the conclusion is plausible and may be useful as a way to reduce commissioning time, otherwise I would also want to understand the mechanism for the reduction before trusting the summary, because conservation of energy says that the reduction must come from somewhere!

I will read the paper itself in the next few days but it would be foolish in the extreme to take the summary at face value without a deeper dive into what the paper actually says.

I must say that I find this sort of slop annoying in the extreme.  The guys at Salford have a very expensive and valuable facility which could be used to answer questions that could change the way we install heat pumps.  Instead the summary, because it omits to specify the control, says nothing but will mislead many.

@jamespa I too will have a browse on the full 84 pages. But one thing jumped out at me on the summary, the radiators were sized to true room need giving a total 4% over-size of system. That might be much more accurate than a real heat loss survey and install. So in their experiment the TRVs don’t have turn down much and are just balancing and the savings are wrt some too warm rooms. That’s the prejudice that I will bring to my reading(!)

But if they model it that might allow an extrapolation to worse situations.

Posted by: @judith

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@jamespa I too will have a browse on the full 84 pages. But one thing jumped out at me on the summary, the radiators were sized to true room need giving a total 4% over-size of system. That might be much more accurate than a real heat loss survey and install. So in their experiment the TRVs don’t have turn down much and are just balancing and the savings are wrt some too warm rooms. That’s the prejudice that I will bring to my reading(!)

But if they model it that might allow an extrapolation to worse situations.

Another thing I noticed in my quick skim was a graph showing steadier temps with ordinary trvs than with smart trvs which made me wonder whether the ordinary ones were acting in analog mode not on off, perhaps because the room was almost balanced.  If this is the case it would be really interesting.

I'm sure there is interesting stuff buried in here it's just a pity that the summary is meaningless, because that's the only bit most will read.

I've just seen reports confirming that Freedom Heat Pumps, the company originally founded by @grahamh back in 2010, is closing down.

According to an update from the business itself (via Certas Energy), following a detailed strategic review they have decided to wind down operations in response to "significant structural changes in the heat pump market". It's not administration... they're managing the transition to minimise disruption for customers and installers.

The Companies House figures back this up and show a worrying trend: turnover fell from £15.7m in 2023 to £11.8m in 2024, then dropped sharply again to £5.8m in 2025, flipping the company from profitable to loss-making.

I have to say this isn't a great sign for the heat pump sector as a whole. It feels like there's been far too much optimism about rapid scaling and adoption from a pure business perspective, while critical issues like installation quality and real-world performance get sidelined. Until the industry properly addresses those, consumers won't feel confident making the switch, no matter how many incentives or targets get thrown at it.

https://www.theguardian.com/business/2026/apr/17/rachel-reeves-to-raise-windfall-tax-on-low-carbon-electricity-generators

It has been floated before, move to basically fix the price of all the old ROC subsidised renewable energy to make them more like CfD subsidies and stop them making eye watering profits.

This may impact what some of the new CfD bids are in future rounds as companies will be wary of what future governments will do around taxation.

Be interesting to watch where it all nets out with actual domestic and non domestic bill in years to come. 

Posted by: @jeff

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This may impact what some of the new CfD bids are in future rounds as companies will be wary of what future governments will do around taxation.

 

Thats always going to be a risk for companies that, in some circumstances, make huge profits from public utilities or essential services,  Rightly so IMHO, and surely they must factor that in.

I do sympathise with those trying to construct 'fair' terms of contract for this sector or any other essential utility.   I reckon its near impossible to come up with something that is guaranteed to survive all of the various ups and downs which occur in the world during even 25 years of operation without, at some point, the utility either making excess profits or declaring it uneconomic to continue, as well as being proof against naked asset stripping at the taxpayers' expense such as we have seen with the water companies and doubtless several other scams.   At least we can deal with the first of these through taxation!

Carbon tax is going from our bills which we have talked about on this thread before.

https://www.reuters.com/sustainability/climate-energy/britain-scrap-carbon-tax-electricity-generation-april-2028-2026-04-16/

This goes into the general taxation pot so the Government will have to replace with some other sort of tax  tweak not connected to our bills as government expenditure generally shows no sign of falling.

Posted by: @jeff

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This may impact what some of the new CfD bids are in future rounds as companies will be wary of what future governments will do around taxation.

It's not just taxation which they must be wary of.

The CfD itself can be withdrawn, leaving investors with no guaranteed income to look forward to.

That happened last month to the southern-most trial site for the Celtic Array.
Phase-1 was to generate only 100MW using Floating Offshore Wind (FLOW) turbines off the Cornish coast.

But DESNZ issued a directive at the end of March which required Ming Yang to withdraw from its role in the manufacturing partnership.
That leaves the consortium without the hardware with which to implement the project until a new manufacturing partner can be found... at increased cost.

Posted by: @jeff

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Not sure if this has already been posted and I haven't read the report. Just posting in case anyone wants to read 

https://www.pv-magazine.com/2026/04/17/thermostatic-radiator-valves-can-reduce-energy-consumption-in-air-source-heat-pumps-by-6-8/

I have now read the report which is indeed interesting. 

Summary

The starting point (ie control condition) is a house operated on pure WC with WC adjusted and radiators balanced for a 21C room temperature in all rooms.  The experiment is performed with an average OAT of 4.5C, either a constant 4.5 or a few degrees of diurnal variation.

This starting point is compared to the same house in the same conditions, but with the temperatures in the bathroom, one bedroom and the kitchen only (representing 47% of the total heat loss) reduced by 2-3C by one of three methods:

• Using the lockshields
• Using a Smart TRV (Schneider Electric Drayton Wiser)
• Using a conventional TRV (Danfoss RAS-C2)

All three methods reduced the overall energy consumption by 6-8%, which is absolutely no surprise because, if house temperature is reduced it is expected that energy consumption will reduce.  There were minor differences but these could be attributed to the difference in the effect on house temperature, not a difference in the effectiveness of the measure. 

Perhaps the most interesting observation is that the Smart TRV method showed a distinct cyclic pattern to the resultant room temperature (corresponding presumably to an on/off control), but the conventional TRV pattern did.  This suggests that the conventional TRV is operating as an analogue flow regulator not on/off.  Conventional TRVs do have an analog band albeit they can ultimately switch off entirely, and it is quite plausible that, if the conditions are such that the room temperature will, in the absence of the TRV, settle close to the desired value, then the TRV operates entirely within its analog band, in other words it operates just like an LSV would.

Conclusion

So, in terms of the headline conclusion that the paper leads with: "Thermostatic radiator valves can reduce energy consumption in air-source heat pumps by 6-8%" this is meaningless/misleading as expected. 

A correct summary would be "In a heat pump system which has well adjusted weather compensation and reasonably well balanced emitters, TRVs can be used to adjust down the temperature of some rooms by a modest amount (eg 3C) and the effect of this on energy consumption will be no different to the use of LSVs to achieve the same objective.  Furthermore, it appears that the conventional TRV tested will operate as an analog controller in such a set up, whereas the smart TRV is on/off.  The former results in a much more stable room temperature, similar to that which would be achieved if adjustment is done on the LSV. 

Consequences

This is interesting and suggests strongly that the frequently suggested option of using TRVs in bedrooms and balancing the rest of the house on LSVs is likely to result in a very similar energy consumption to operating fully open loop with LSVs adjusted to trim the temperatures of some rooms down.  For good installers this is useful knowledge.  For poor installers this is dangerous, as they wont get the subtleties and will wrongly think that fitting TRVs universally is the solution to their problems. 

In fairness to the authors they do say, in their conclusion: "People with ASHP systems should be made aware that TRVs should be used as a secondary measure to reduce internal temperatures. To ensure the most efficient ASHP operation, the initial course of action should be to reduce the flow temperature until the worst performing room reaches a comfortable temperature. TRVs should then be used to trim temperatures in other rooms." 

Its a pity the same sentence wasn't repeated in the summary!

Posted by: @editor

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it feels like there's been far too much optimism about rapid scaling and adoption from a pure business perspective, while critical issues like installation quality and real-world performance get sidelined. Until the industry properly addresses those, consumers won't feel confident making the switch, no matter how many incentives or targets get thrown at it.

Looking at the monthly Boiler Upgrade Scheme statistics, it's hard to understand the cause of the optimism, the number of actual claims being paid floats between 2,000 to 3,000 per month. It varies a bit, like when there was concern BUS might end of restricted, when number of new applications ticked up a bit, but then it dipped again once that blew over.

It does not look like heat pump uptake is really growing at anywhere near a decent rate, barely at all, it looks like the retrofit side of the market supported by BUS is pretty stagnant, hitting a ceiling somewhere around 3,000 units a month. Which is pretty insignificant compared to gas boiler installations.

You have to wonder what the situation is like for all of the bigger operators (Octopus, Aira, BOXT, BG, EON, etc) now active into the market, what are they all doing if those BUS numbers are not growing?

Posted by: @editor

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The Companies House figures back this up and show a worrying trend: turnover fell from £15.7m in 2023 to £11.8m in 2024, then dropped sharply again to £5.8m in 2025, flipping the company from profitable to loss-making.

I have to say this isn't a great sign for the heat pump sector as a whole. It feels like there's been far too much optimism about rapid scaling and adoption from a pure business perspective, while critical issues like installation quality and real-world performance get sidelined. Until the industry properly addresses those, consumers won't feel confident making the switch, no matter how many incentives or targets get thrown at it.

In 3 years on this forum I cant honestly see that anything material has changed in the industry.  There are still good installers doing a great job and poor installers reliably making the same few mistakes.  Octopus shows that it can be done at scale with people that can actually be hired, but they seem to be alone in this.

I am now firmly of the view that the systemic problem causing poor installs is methodology, and that the solution is production engineering of the install process.  Currently the methodology relies on installers being both excellent and diligent, and we can never expect that to scale because its just not the human condition.  So we need to stop trying to make every installer excellent and instead redesign the methodology so they don't have to be.  Octopus have clearly cracked that, whether that is because they are vertically integrated or just because they have thought about it the right way I cannot say.

Until this is done we cannot IMHO scale and simultaneously expect reliably good results.  In the interim therefore we need somehow to arm consumers with the information they need/questions they need to ask to weed out the rubbish.  Given that its the same three mistakes* almost every time I cant see that is impossible, the challenge is getting the information to them.  This forum has, imho, a part to play, and the good installers who visit here could perhaps help (and possibly even benefit as a result).

Stimulating demand is a separate problem which there is little chance (and questionable morality) of solving until we can deliver reliably.  

It's worth adding that the NESTA survey in 2023 suggests that the satisfaction rate with heat pump installs is, in broad terms, no worse than the satisfaction with boiler installs.  The problem is that this isn't good enough because people will inevitably blame their dissatisfaction on the new technology rather than endemic industry mediocrity.

* Unnecessary buffer tank/llh/phe, oversized heat pump, wrong/wrongly set up controls