How hard will it be to scale up heat pump capacity in the UK?

I want to challenge the assumption that scaling up heat pump capacity in the UK is very hard. 

In many ways this belief is symptomatic of a wider malaise in the approach to skills we have had in the UK for far too long. Maybe the crisis in energy – and particularly gas – now confronting us is the jolt we needed to do a rethink.

Scaling is only hard if we still frame the challenge in the same ways we do today – in terms of number of certificates gained through further education colleges. This is not the answer. 

We need something far more like the apprenticeships of old – not those where all the money pours into the colleges, but one where the firms who are doing the real competency development through practice get a decent share of the funding.

Another implicit assumption that needs challenging, is that we need to create clones of experts with very deep heat pump expertise. I don’t think that is true (except maybe in very hard or non-standard outlier cases). In all technologies, as they mature, there is an element of de-skilling that takes place. 

An example is software, where modern tools alleviate a lot of the skills hitherto required in, for example, creating a web site. Although this can reframe the skills question, and quite different design skills can emerge (e.g. illustrators rather than coders).

Heat pumps have matured to the point where we are near to this point (but they still have some work to do to simplify their manuals further).

Finally, we need to scale up the number of heat pump SMEs (Small and Medium sized Enterprises). A massive strategic blunder would be to see the challenge as retraining 100,000 existing one-man-band boiler fitters/ plumbers, to turn them into 100,000 one-man-band heat pump fitters/ plumbers.

A new SME-led approach would put the emphasis on competency development and rebalancing the training budget, with more of the funding going towards the SMEs who can grow the right skills, and do this organically.

We may still need training colleges, but we have to accept that the current model is broken and it is not fit for purpose, and certainly not for our current emergency; their role needs to be radically transformed.

If a heat pump project is broken down into its distinct roles and competencies, the challenge becomes much easier. 

In what follows, I am assuming an air-source heat pump (ASHP) and a ‘wet’ heat distribution system (pipes and wall-mounted radiators), as this will apply for the overwhelming majority of homes that need to transition from gas boilers (to be ‘retrofitted’).

Meet the total UK team that would be needed to install 1,000,000 heat pumps a year by 2030 [1]:

  • 9,000 electricians with expertise in configuring heat pumps.
  • 4,500 assessors/ designers to assess a property, carry out heat loss calculations, and size and design the whole system (heat pump, hot water tank and radiators). This is the most critical role to ensure the overall system design performs to the efficiency expected.
  • 45,000 plumbers required to follow the designs given to them, but not to understand heat pumps in any depth.

Britain with the help of its allies trained 100,000+ pilots in WW2 in just a few  years, and many more women and men building the planes. They didn’t do that by sitting them in classrooms, trying to get them to understand aerodynamics! They got plonked into two seaters and were soon taking the controls.

We need to be honest about the malfunctioning monetised approach to technical training in the UK (actually, most ‘higher education’), and instead focus on practical skills, competency development, and real world practice / achievements. I recommend a great discussion on the issue of ‘resources not courses’ [2]. 

I asked a plumber who was part of the team that installed the heat pump in my house about his college training. He told me “I didn’t get much out of it. I only really learned what I was doing when I left college and started work, and it took a few years to gain my confidence”.

The individual tasks involved in assessing, designing, installing and commissioning a ‘heat pump system’ can be broken down and assigned to roles with the right skills.  I have outlined the project in the notes [3].

The interesting observation is that the plumber is the role which puts in the most hours on the project (to do traditional things like bending copper pipes), but requires the least level of knowledge on heat pumps. They just need to follow the design handed to them. So scaling capacity, if targeted effectively, can be very effective. I have included a skills table in the notes.

The assessor/ designer who was on the team that installed the heat pump in my house – let’s call her Chloe – was a physics graduate in her late 20s. She made easy work of the assessment, calculations and design, and putting together the proposal for the overall solution.

In 10 years, would it really be so hard to scale an SME-led model, including cross-trained electricians and plumbers, and developing a new career path for ‘heat pump assessor/ designers’ like Chloe?

Let’s not talk ourselves into defeat.

We just need to get smart, and organised, and fund the right things.

© Richard W. Erskine, 2022


[1] Estimate of roles required for a typical dwelling

Average man-days
per house
Workforce required for 1,000,000 installation per year,
assuming 230 working days a year
Assessor/ designer14,348
Electrician/ configurer28,696

Note that 10 man-days per house, would typically mean 2 plumbers for 5 days.

[2] Resources not courses

There are deep issues with teaching and training in the UK. The marketisation of education and training means that further education colleges are paid for accrediting students, not developing true competencies. There is a great discussion on this in relation to heat pumps at the BetaTalk – The Renewable Energy and Low Carbon Heating Podcast in the episode The Training Fiasco in Plumbing & Heating – I am certainly not claiming there is an easy way of fixing the training issues in the UK. I am simply saying we can reframe the problem through better organisations and coordination of the roles and skills.

[3] Project outline

  1. Assessment of the heat loss of the house in its given state of fabric, in order to ensure that the heat pump can deliver the peak load required, during the depths of winter. This must be done room by room to ensure correctly sized radiators in every room. Other aspects to be assessed are the existing pipework, radiators, power supply and water pressure.
  1. Design of the whole system, including the air-source heat pump (ASHP), and requirements for hot water, and radiator heat distribution. Any upgrades of radiators will be part of the design, as well as decisions on the peak flow temperature required.
  1. Installation includes several tasks. Physical installation of the ASHP and associated kit (control system, buffer tanks, etc.). Connection to the electricity supply. Connecting the heat pump sub-system to the existing pipework, and upgrading any radiators as per the design. Then ‘balancing radiators’ to ensure optimal heat distribution.
  1. Commissioning involves configuration of the controls (including ‘weather compensation’) to maximise the efficiency of the heat pump during all weathers, and enabling effective energy monitoring so that the customer can see how well the system performs over days, months and years; and finally, ensuring all the paperwork is completed with certification authorities such as MCS (Microgeneration Certification Scheme).

Each hands-on role can be addressed differently in terms of scaling capacity. We will need:

  • An assessor/ designer, who can also play the role of designer, and needs a high level of knowledge of the overall system aspects.
  • A plumber who will do pipework and deal with physical kit installation, but requires only limited knowledge of heat pumps.
  • An electrician/ configurer with high skills in the specific heat pumps installed, and their controls.

Other roles not directly involved are management, accounts, supply chain/ store manager, sales & marketing, and these are important as in any similar business, but don’t ‘scale’ anywhere near as fast as the hands-on roles.

Here is how the the hands-on roles match the stages in the project:

Assessor/ DesignerPlumberElectrician/ Configurer




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3 responses to “How hard will it be to scale up heat pump capacity in the UK?

  1. Richard, I agree with almost all you write here. We absolutely can scale up heat pump deployment and those that say otherwise often either want to hold on to a cottage heat pump industry where everything is hard (and therefore expensive) or have a vested interest in keeping their network of yellow pipes in the ground profitable. My employer, the Kensa Group, has a vision of mass heat pump rollout that by it’s nature deskills the installation, tackles the issue at scale (street by street, not house by house) and removes the upfront cost barriers you have previously identified for the lowest carbon and lowest running cost systems.


  2. Pingback: Heating a listed Cotswold stone building with an air-source heat pump: our journey | EssaysConcerning

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