BLOG: France versus the UK: the great heat pump contest
We ought to relinquish the implicit assumption that UK housing stock is so similar to that of our European neighbours that it does not warrant attention when it comes to […]
Published: 8 Aug, 2023

We ought to relinquish the implicit assumption that UK housing stock is so similar to that of our European neighbours that it does not warrant attention when it comes to the question of decarbonising our heating – and, in particular, when it comes to the widespread installation of heat pumps.

Recently, The Guardian revealed that France (Europe’s largest heat pump market) is currently installing ten times more heat pumps per annum than we do in the United Kingdom. The UK installs around 55,000 units per year, and France installs an enviable 600,000. The article has a laudable premise: how is it that France does what we aspire to? Put another way, the author suggests the UK is capable of achieving anything France can – provided we understand the basis for France’s success and implement a similar regime here at home. But here’s the rub: do we understand the basis for France’s success (or, indeed, the foundation for our relative failure)?

The Guardian article was informed by a June 2023 report titled, “Heat Pump Rollout in France and the UK: A Comparative Analysis,” prepared by MCS Charitable Foundation. This is an excellent report. It offers insightful coverage of the institutional and historical differences between France and the UK, as well as an exacting account of the various policy initiatives put forward by the French and UK governments in aid of their respective decarbonisation and net-zero targets.

Despite these strengths, however, there is no discussion of housing, whatsoever.

This ought to puzzle readers given a heat pump is a piece of technology that only exists in the context of a home. Heat pumps are not disembodied devices hovering in space that produce zero-carbon heat. Heat pumps are affixed to actual existing homes, and they heat actual existing spaces. Consider the mundane process when someone wants to get a heat pump installed. After the installer has made a physical inspection of the property, they give the homeowner some idea of where the unit can be installed, and whether the home requires fabric or heating system upgrades to permit the heat pump to perform to the manufacturer’s specifications (preferably a COP of 3.0 or higher). It is only following these recommendations that the homeowner decides if they have the finances, time, or inclination to continue with the heat pump installation.

According to a recent Nesta survey of UK heat pump performance, over 55% of homes required some form of fabric upgrade: loft insulation (36% of cases), wall insulation (23% of cases), and/or double or triple glazing (23% of cases); while, “53% of heat pump installations involved replacing the entire heating system”: new controls (72%), new radiators (68%), and new pipework (55%). It is clear that, in many cases, installing a heat pump involves considerable expense and disruption above and beyond the mere installation of the unit. This is relevant since, as Catapult Energy Systems uncovered, a “commonly reported reason for participants not wanting to proceed with a heat pump installation was the disruption that the installation would cause to their home. This includes replacement of pipework, impact on décor, etc.” ‘Hassle factor’ is a major barrier to the adoption of heat pumps.

Not everyone, however, agrees with this logical assertion.

(Contradicting their prior findings,) Nesta’s most recent policy report states: “Contrary to widely held beliefs, heat pumps do not require high levels of insulation to work effectively. A heat pump system can efficiently heat almost any home as long as it is properly designed.” This assertion (which defies the laws of thermodynamics) is based upon the headline from the 2023 Catapult report which reads: “All housing types are suitable for heat pumps.” There is a fundamental problem, however, with a face-value reading of Catapult’s claim and Nesta’s subsequent conclusion. The Catapult demonstrator trial does not support such an interpretation. On the contrary, the Catapult report discloses:

“Many of the properties that had a heat pump installed already had suitable levels of loft and wall insulation, in part because harder to insulate properties were ‘triaged out’ at earlier stages of the project.” This admission, then obliged the Catapult researchers to concede: “Suitability of the wider UK housing stock for heat pumps should therefore not be inferred based on this data.”

The empirical evidence is clear: for the majority of existing homes in the UK, the installation of a heat pump will require fabric and heating system upgrades – if the unit is to perform to the manufacturers’ specifications.

Returning to the Guardian article, and the comparison between France and the United Kingdom. A pan-European comparative analysis undertaken by Imperial College in 2022 titled, “Decarbonising Buildings: Insights from across Europe,” reported that “homes in the UK typically lose more heat than homes from any of its European neighbours, in some cases losing heat up to three times as fast.” This finding (originating from a 2020 study by tado°), compelled the Imperial researchers to investigate differences in building, thermal, and energy efficiency standards across Europe. Imperial found that due to a legacy of inferior building practices, regulations, and standards, UK homes are older, leakier, and less well insulted than their European counterparts. Imperial reports, “heating systems within the UK are having to work harder and use significantly more energy to maintain the required temperatures than in comparable countries.”

All of this is to say, we ought to relinquish the implicit assumption that UK housing stock is so similar to that of our European neighbours that it does not warrant attention when it comes to the question of decarbonising our heating – and, in particular, when it comes to the widespread installation of heat pumps.

Fine. But, so what? Am I not simply making the perfect the enemy of the good? Don’t the Guardian article and the Nesta and MCS reports advance the mass adoption of heat pumps (their neglect of UK housing notwithstanding)? Yes and no. When you ignore the actual-physical reality of UK housing stock, there is greater uncertainty in the data, and this uncertainty leads to unintended outcomes – especially in the context of policy recommendations.

The Guardian article makes four policy recommendations for government: (1) mandate heat pumps in all new homes; (2) increase funding for installations in existing homes; (3) ‘green finance’ initiatives; and, (4) awareness campaign & one-stop-shop. The first recommendation is absolutely sound. It is rather shameful we have allowed around 1,300,000 new homes to be connected to the gas network since March 2013. However, since the UK completes less than 250,000 new homes per year, a mandate on new-builds gets us less than halfway to the government’s magic number of 600,000 heat pump installs per year. The majority of heat pumps will, therefore, need to go into existing homes.

The Catapult report found the “average total cost per property was about £14,800 including the heat pump unit [and the] additional measures and installation.” Assuming this figure is reliable, the £5,000 offered by the government’s Boiler Upgrade Scheme only covers about a third of the average heat pump installation (far less if you go with a ground source heat pump). Since 50% of Brits have less than £1,000 in savings and 23% have none at all, heat pump schemes will need to be a lot closer to the actual total cost of installation if homeowners are to be expected to take them up. Given the stop-start, erratic nature of UK government schemes offered to date were cited in the MCS report as a primary reason for low heat pump uptake in the UK, withholding the full extent and nature of the costs involved is akin to setting the government up for failure.

Finally, a critical component of any one-stop-shop offering advice to homeowners about the installation of heat pumps is to inform them of what kinds of works – and over what period of time – will be required to bring their home to a fabric and thermal efficiency standard to ensure their heat pump performs to the manufacturer’s specifications. This would go a long way to overcoming the ‘hassle factor’ that is presently a huge barrier to the mass adoption of heat pumps.

Many differences between France and the UK have indeed contributed to their success and our relative failure to install heat pumps on a massive scale. One of the most important differences, however – that many investigations seem to set aside – is the path dependency arising from a legacy of suboptimal building regulations, standards, and practices, that have left UK houses leakier and less thermal-efficient than most of our European neighbours.

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