Hi, didn’t really know what category to put this in, so feel free to move it. Across this site and the renewable heating site there are lots of issues arising with heat pumps. Yet supposedly the government wants to speed up the rollout, I would argue there are so many basic infrastructure issues to address a cautious approach is advised, whilst addressing the existing multiple problems. The Resolution Foundation is holding a webinar to discuss how the rollout should be driven. For anyone interested it may be a good place to raise critical issues and get a wider audience.
@Terry247 What do you see as the issues to solve? Grid stability/capacity? Poor installation quality driving poor performance and potentially bad perception of them?
@cccharles , for me problems with the cost and availability of maintenance, which is a double whammy because you have to have the maintenance to keep the warranty. That heat pumps are far more complex than gas boilers and I’m not sure that everyone will have to spend hours of times trying to figure out what is going on. The latter which proves necessary because of poor post installation support and clearly problems with both installer and suppliers not being willing or able to help customers with the myriad issues that crop up. Also given those factors the price of electricity becomes a major factor, because if people aren’t getting a cop of 4 or better then there costs are most likely to be higher than with gas. That all costs for transition to net zero are dumped on the electricity costs is very problematic. Infrastructure, being the availability of maintenance, sufficient quality installers etc. But there don’t seem to be any standards and enforcement even to MCs standards is low, but from my discussion with MCS they don’t regulate, there are eight bodies that do.
I’m not sure I totally agree with all of that, but there are some points that are definitely right! To tackle them individually:
Maintenance is expensive - It is because there is less volume than boilers/aircon, but the complexity of a boiler is actually higher. A heatpump is just a fridge in reverse so not particularly complex, and most of the complexity comes from the plumbing setup. I feel like this is a solvable problem, as demand increases the engineers who are trained on air con can also look at heat pumps easily. Maintaining a warranty and hence needing the service is something many people dont do on boilers, so it is a choice, but its more of a risk especially on a new expensive device. I think there will be a ton of movement in this space as volume increases and average age of heatpumps increases…
Complexity - this one is a bit tough as there are a few parts to it, installation complexity should improve quite quickly as knowledge builds from users and installers, but user experience improvements probably require new tools/training/systems/automations. This latter part is needed to open up heatpumps to the wider public anyway, but any internet controlled device can have tons of automation added in the future very easily, so again I think solvable if people install web controlled devices. At the moment, getting a good installation relies (a lot) on savvy customers, but it will take time to get the right regulation and remove cowboys (though many industries still struggle with them). This is probably the top challenge in my mind, along with associated bad PR for heatpumps when somebody has a bad installation.
Price and Efficiency - I think a COP of 3 should still be pretty close to cost saving tbh, especially as energy prices move around with increasing green electricity - if there are more heatpumps to take offpeak (somewhat flexible) electricity then it can be VERY cheap. Gas can only get comparatively more expensive in the future. However plenty of installations dont meet COP of 3, for sure, and is probably the area of focus for the industry. I would say that many houses are actually pretty easy, hence its not super complex to get these right with basic installer knowledge, but its got a long tail with difficult houses. In addition to this, insulation can be expensive, and if this isnt fixed at the same time it could mean a badly designed system in the future when insulation is eventually added. I dont think these points should cause a delay to the rollout, as at current trends the grid and generation are changing faster than residential demand for heatpumps increasing.
To my mind the most critical issue is only slightly related to the heat pumps themselves.
The central heating industry has built up several generations worth of bad practice in heating system design and use. Its so bad that gas boiler systems got to the point where they were never really designed at all. Just count the number of rooms, put a radiator under each window the same size as the window then put in a gas boiler the same size as that used in the last job on a similar sized house. Or a bigger one if that was what was on special offer down the builders’ merchants that week. Whack the system temps up to 75c and Job done, nice hot radiators and everybody happy.
Now we are seeing heat pumps being advertised as “high temperature” and punted as suitable as a direct replacement for any existing gas boiler. Its a disaster waiting to happen as the cowboys latch on to the “direct replacement” theme, bung one in and run. Cue yet another Telegraph article on how a heat pump will never be able to keep your house warm and costs you a fortune to run.
Quite how you fix this, I am not sure, but never comparing a heat pump directly to a gas boiler would be a good start and not deliberately setting out to produce a heat pump that pretends it’s a gas boiler might be a very good move in the longer term.
A few £k of batteries will radically reduce electricity costs and battery are quickly dropping in cost. So using a high temperature heatpump as a direct boiler replacements without the labour cost of charging pipework/radiators maybe the most economical way to get off gas without increasing heating costs.
I think you have rather missed the point I was trying to make. We have a vast pool of gas boiler powered heating systems that present a huge opportunity to replace them with something much better IF we take the right approach and take the time to design and operate them properly.
The cavalier and lazy approach to design in the past has resulted in systems that are often vastly over-engineered and will work fine without replacing the pipework and radiators even with a low temperature heat pump, provided it is used correctly. High-temperature heat pumps used indiscriminately will just encourage users to keep on operating using the old gas boiler rules of thumb so they will not get the benefits of doing things efficiently and will pay more over time.
If a high temperature heat pump is really the only solution then so be it but it should be a last resort not the default.
Or have a “AI” system in the high temperature heatpump so they learn how the building responds and automatically operates as a low temperature heatpump when possible. Ideally also use some sort of smart TRV to automatically balance the system and then recommend if a radiator upgrade will give significant running cost reduction.
(I don’t care what temperature the living room have overnight or what temperature bedroom have in daytime, so why can’t heatpump do whatever is lowest running costs.)
Part of the problem is no one can predict how well a system will work with existing pipework without lifting all the floorboards to inspect the pipework. Likewise not practically to predict untightness or heatless as part of a “free” quoting process.
Nice idea for the AI. Low temp systems would benefit too. Ideally the high temp part would be an optional upgrade that could be added to the basic low temp system part after install and only after the low temp version has been tested.
Solar uptake has accelerated so you now see them everywhere and is hopefully the track for heat pumps. One issue is that you see solar so people are encouraged to consider it for their own house. Perhaps we need some evidence that a house has a heat pump - such as a green plaque on the house that stays around for their neighbours to see - perhaps for a couple of years. My son is getting one after I did, so word of mouth and shared positive experience.
I think the maintenance issue is not upfront for most people considering one. That comes later. The issue is initial cost, disruption and over coming myths about running costs and performance in cold weather.
Overall, solar took a while to get going, as did e.v.s, so perhaps the hp uptake is on trend. Though more can always be done.
I don’t know what’s best from a policy perspective, but do wonder about the financial sustainability of the current high subsidy rate, It would be good to avoid the boom bust cycle seen over the years in the solar industry and have long term visibility on how the subsidy will change in the future.
I think where existing radiator systems are old and need changing anyway or in new build, new designs should be encouraged to target 40C flow temperatures (gold standard), 45C (silver standard). Otherwise cost cutting will target 50-55C flow temperatures on new radiator systems locking in higher running costs (40C being much easier to achieve with accurate heat loss calculation).
On existing radiator systems where the financial benefit of upgrading is calculated to be marginal, flexibility in the heat pump installation standards to allow designs for 50C seems fair enough.
The key though as we see from the Electrification of Heat data is that regardless of the design flow temperature of the emitter system, a lot of systems are not controlled well and run at average flow temperature that are quite a bit higher than the design and certainly the real world heat loss could allow.
@TrystanLea , I absolutely agree that we should be aiming for a lower design temp, because otherwise we’ll be doing what we’ve been doing with gas, which is using it wastefully. On the subsidy point it is high but at least unlike solar panels it’s a one off.
Running my Samsung HT at up to 50 deg C increases the heating cost by only 8%.
Basic battery storage will effectively result in half price electricity for heating resulting in the annual cost of space heating equal to or less than natural gas without any compromise to the homeowner other than needing to have the heating on all day.
The fundamental issue raised by the OP is that we need to avoid excessive installation cost, plant rooms and complexity when converting existing properties. (New builds would always gravitate to low temperature emitters of course but that is not the target for the great UK switchover to heat pump).
We need to remember It is not just a matter of heating efficiency but rather overall commercial effectiveness of the rollout. The primary aim is to start using renewable electricity for heating and not fossil fuels as soon as possible.
A CCGT is around 50% efficient and distribution losses are around 6%. A typical household condensing boiler is 90% to 95% efficient. So I make that a COP of more than 2 required for less natural gas carbon emissions.
Operating a heat pump will always result in less carbon emissions even at the lowest COP.
I have just watched the Resolution Foundation discussion as linked by the OP at the top of this thread. It seems the main concern is the very low installation rates of heat pumps for the middle to low income households (i.e. the vast majority). The BUS grants are mainly going to wealthy home owners in rural areas and take up by the others is being hampered by the uncertainty and disruption as well as cost.
Lowering electricity tariffs at the expense of natural gas is proposed and loans that are then repaid by future savings on energy bills may have to replace grants. Reducing delays with approvals and with more categories allowing air to air heat pumps as well as HT. More efficient heat pumps was mentioned only briefly. Using EPC was singled out as not fit for purpose and proposing heat loss measurements to replace it.
Lots of interesting observations I recommend watching it.
A good recommendation with a good video debate.
The presentation highlights some basic facts surrounding the lack of affordability of ASHPs in typical UK households. The uptake of ASHP is less than ~1% of the installed gas boilers in UK homes, even with a full BUS grant. The ASHP is still too expensive to install and operate for the typical household without other costly products (eg solar, battery storage for night tariffs, etc). The video highlights an excellent point to rebalance the electricity and gas bill levies. Unfortunately, the UK has the highest electricity/gas ratio in Europe. The UK has one of the highest electricity bills per kWh combined with one of the lowest gas bills per kWh in Europe. See the table below. The present electricity/gas ratio is 3.89. You would need a very good SCOP approaching 4.0 to be notably cheaper than a gas boiler. The present UK energy market appears to have an uneven playing field compared with other European countries. If the 16% levy on electricity bills was swapped with the 4% on gas bills, then the Electricity/gas ratio falls to 3.09. That makes it notably cheaper to operate an ASHP compared with a gas boiler. In my opinion, a rebalanced UK energy levy is needed to help increase the uptake of ASHPs in the UK. It still does not address the high up-front cost of the ASHP, or the UK government policy decisions surrounding the phasing out of gas boilers for new builds or for future home sales.
It’s worth noting that actual running efficiency can be way lower, until last year there was no regulation to actually commission a 98% efficient boiler in a way that ran at that efficiency.
Ultimately I think the UK will need a utility level obligation scheme. Where a minimum quota is foisted on suppliers.
A real missing link is a combination of small heat pump, 10kwh of battery and a high-power Immersion that the battery enables. We need to stop thinking about 3kw immersions and design a compact system that utilises a LFP battery discharge rate to provide say DHW boost @ 10kw or more even at 100% efficiency would be enough to cover scenarios people worry about. It’s a huge amount of instantaneous power that requires no extra work (wiring) at the domestic level, as you’d incorporate it into the appliance. This would erode the whole “design for the 2 days of the year it’s cold” mentality too and when not needed to boost acts as storage for the home. Especially if that 100% efficiency energy is tax free or charged from cheap tarrifs.
I agree. The package for heat pump heating should incorporate battery storage so that off peak tariff is effectively half price electricity all day and saving on grid distribution capacity. Currently my annual average daily tariff is 15p on Octopus Cosy and provides 5p/kWh of heating with an average COP of 3 -significantly less than natural gas price without chasing hard to achieve higher COP values on existing radiators.
Replacing fossil fuels with electric heating as fast as possible with the least cost and disruption is the prime objective here.
This HP/battery storage package could be installed externally in most cases without intervention to the internal radiators and pipework. The bespoke part we are currently required to install inside the home is so costly and unpredictable it will continue to hold back a mass electrification take up on existing UK properties.
