Written evidence submitted by Warmur (WFP0135)

Hydronics: the missing link in the UK's Clean Energy Mission for homes

Jo Alsop, Co-founder Warmur/Warmur Academy

We are Warmers

Warmur exists to help everyone transition to a more sustainable home by providing tools, services and impartial advice that meet households where they are and help them make changes even on a tight budget.

We are powered by Warmur Network, a group of the UK’s top independent heat pump installers, and Warmur Academy, where we upskill heating engineers to confidently design and install efficient heating systems through a comprehensive understanding of hydronics.

Introduction

The UK’s ambition to decarbonise homes by 2050 requires a large-scale transition to heat pumps. However a widespread lack of hydronics expertise among heating engineers threatens the speed and success of the transition. Hydronics - the science of heating with liquids - is fundamental to the efficient operation of all modern heating systems, whether condensing gas boilers or heat pumps. Yet this knowledge is largely missing from installer skill sets, leading to higher energy costs and carbon emissions.

The Heat Pump Association (HPA) estimates that 50,200 heat pump installers will be required by 2030 to meet the Government’s target of 1 million annual installations[1]. While the UK’s existing 108,000 registered domestic Gas Safe engineers could be a major source of skilled labour, most heating engineers have been trained using outdated "rules of thumb" methods rather than modern system design and installation principles, creating a hidden skills gap that the current training provision does not fill.

At Warmur Academy, we see firsthand the frustration heating engineers experience because of their knowledge gaps and the inadequacy of the existing training provision to upskill them. When given the opportunity to properly understand hydronics however, we see their light bulb moments and watch as their confidence and enthusiasm soar.

We believe that comprehensive hydronics training for all heating engineers is the key to unlocking a competent and motivated workforce with multiple benefits to their careers and the transition, including:

●        Reducing gas consumption today through better system efficiency.

●        Preparing engineers for heat pumps without overwhelming them.

●        Ensuring every heat pump installed performs optimally.

●        Elevating the sector and fostering professional pride.

●        Increasing consumer trust and accelerating adoption.

In this report, we address the committee's five questions with specific reference to domestic heating engineer skills sets and workforce provision. We provide suggested actions and their impacts at the end of the report for DESNZ and the Office for Clean Jobs to prioritise.

1. Does the Government have an adequate understanding of the skills needed to deliver the Clean Energy Mission by 2030 and decarbonise homes and businesses?

The hidden nature of the hydronics skills gap means that the Government does not have an appropriate understanding of the skills needed. The present thinking is that gas engineers will form the primary source of labour for fitting heat pumps[2] and require only a small amount of retraining via a three-day Heat Pump Installation course and two-day Low Temperature Hot Water course.

Such a limited training provision has to assume that gas engineers have been optimising condensing boilers using good hydronics principles for two decades. In reality, the UK heating industry has continued to rely on "rules of thumb" practices when fitting modern gas heating systems, with minimal emphasis on the theoretical foundations of hydronics so crucial to their performance.

This omission has gone largely unnoticed as condensing gas boilers still operate even when poorly set up and efficiency underperformance has been hidden by low gas prices. As the industry transitions to heat pumps however, where precise hydronics knowledge is essential for optimal performance and comparable running costs, this hidden skills gap is increasingly exposed.

The legacy of unoptimised boilers

Condensing boilers are not inherently 90%+ efficient, with most only achieving 75-85% efficiency in the home[3]. The performance shortfall from advertised efficiencies is acknowledged in DESNZ’s recent Improving Boiler Standards and Efficiency consultation[4], with proposed uplifts in building control to deliver better efficiencies and reduced running costs for households.

The role installer know-how plays in system performance is not addressed however. Condensing gas boilers are technically ‘low temperature systems’ and should be set up in a way that is closer to heat pumps than to non-condensing gas boiler systems. A lack of training in modern system design has led installers to continue to fit condensing boilers as they would non-condensing boilers, in particular maintaining high flow temperatures and failing to fit a weather or load compensation control. This both drives up heating costs for households and leaves installers ill-equipped for heat pumps.

Heat pump success in jeopardy

Heat pumps are far more sensitive to system design and installation than gas boilers. While a poorly set up gas boiler might lose 5-20% through inefficiency at a cost of £30-115 for the average household, a poorly set up heat pump might lose 200% of available efficiency at a cost of £270.

Common design and installation errors in flow rates, pipe sizing, system balancing and pump selection significantly impact their performance, at best the heat pump will underperform and cost more to run, at the worst the heat pump won’t keep the home warm or prove unaffordable. Heat pump horror stories have made the news many times, but despite the problem being firmly rooted in installer competency it is the technology that suffers reputational damage.

2. To what extent can the Clean Energy Mission and the retrofitting of homes and businesses be carried out by the existing workforce and to what extent will it require new entrants to the workforce?

The current workforce, largely composed of gas engineers, possesses valuable skills that can be adapted for heat pump installation, but the significant skills gap in hydronics needs to be addressed to truly unlock supply.

The lack of training in condensing gas boilers has been a missed opportunity for heating engineers to develop system design skills vital for heat pumps. Training has focused narrowly on gas safety, neglecting transferable skills that could have eased the shift to low-carbon heating. As a result, many engineers are underprepared, making current training options inadequate and fragmented. Developing a comprehensive training pathway is essential for installers to confidently recommend heat pumps and maximise savings for customers.

Training take up

While there has been a recent surge in gas engineers completing the heat pump course, from 3,000 in 2022 to nearly 8,000 in 2023, workforce surveys have shown that only 9% of heating installers had fitted a heat pump and only 11% felt ‘extremely confident’ discussing the technology with customers[5].

To meet installation targets, it is estimated that the UK will need 50,200 heat pump installers to meet 1 million fitted heat pumps in 2030[6], which is nearly half of 108,000 registered domestic Gas Safe engineers. With around 40% of the gas workforce due to retire in the next decade and many disengaged from heat pumps altogether, the available pool of people is very close to the total numbers needed to transition[7].

Leveraging the existing workforce

A strategy that targets existing gas engineers (alongside attracting new entrants to the sector) is key to building a competent heat pump workforce. By teaching all gas engineers the core skill of hydronics we are able to lay the groundwork for heat pumps amongst a sceptical workforce, but 50% of whom are keen on training in new skills for their current roles.[8] To put it another way, hydronics allows all heating engineers to invest in their careers while quietly upskilling for heat pumps well in advance of any decision to tackle this new technology.

3. How might the Government ensure that the job market in clean energy roles is sustainable enough to incentivise private sector investment in training for 2030 and beyond?

To ensure a sustainable job market that incentivises private sector investment in clean energy training for 2030 and beyond, the Government must establish long-term support structures that foster continuous learning and professional development and elevate the trade. Currently there is no CPD-style learning requirement or framework to encourage ongoing skill-building, leaving many heating engineers unable to build on their skills and unprepared to assist in the transition.

A structured approach to lifelong learning through mandated CPD, career progression pathways and financial incentives for training would create stability and confidence in the sector. A key step would be requiring Gas Safe engineers to undertake system efficiency training as part of their mandatory ACS qualification every five years. This would ensure that all heating engineers, regardless of technology, are equipped with essential hydronics knowledge to optimise system performance, reduce gas waste and be ready for heat pumps.

As a training provider specialising in hydronics, we can attest to the transformative effects of high-quality training when heating engineers are given the opportunity. Our collection of over 500 testimonials provide a valuable insight into the willingness of heating engineers to learn, grow and be impactful, but also expose how much is missing from their skills sets:

●        Welcome to a world of actually understanding what’s involved in being a heating engineer

●        Made me rethink everything I thought I already knew about heating systems

●        Wow, opened my eyes completely to what we haven’t been doing right for so long

●        It has given me the confidence to take my career to the next level

●        I feel like I’ve seen the light!

By embedding structured training and mandating system efficiency education, the Government can give the private sector confidence to invest in high quality training, ensuring a skilled and motivated workforce that accelerates heat pump adoption.

4. How can the new office for clean energy jobs contribute to workforce planning in the energy sector?

The Office for Clean Energy Jobs (the Office) has a critical role in ensuring the energy workforce is equipped with the skills needed for a low-carbon future. To support heating engineers in their long-term career development, the Office should focus on structured training pathways, career progression and financial incentives that make clean energy careers desirable and rewarding.

1. Mandating system efficiency training

The Office should require Gas Safe engineers to undertake system efficiency training as part of their ACS qualification every five years. This would ensure that all heating engineers, whether working with gas or heat pumps, have a solid foundation in hydronics, specification and optimisation. This would have the dual benefit of helping gas engineers to reduce gas use today as well as getting ready for heat pumps systems.

2. Creating a national CPD framework

Unlike many other technical professions, heating engineers have no structured CPD requirement. The Office should introduce a national CPD framework, ensuring engineers continually update their skills to keep pace with technological advancements in clean energy. This would help create a culture of lifelong learning, increasing retention and professional pride within the sector.

3. Reforming heat pump training to build installer confidence

Current heat pump training is too short and product-focused, leaving many installers ill-equipped to confidently install or advocate for heat pumps. Most programs do not cover essential hydronics principles, meaning engineers struggle with system design, sizing and troubleshooting. This lack of confidence directly impacts customer adoption, as hesitant engineers are less likely to recommend heat pumps.

The Office should review and reform heat pump training, ensuring it incorporates hydronics, boiler efficiency and real-world installation scenarios. This will increase installer confidence, improve system performance and accelerate consumer uptake of heat pumps.

4. Financial support for career development

Many independent heating engineers and small businesses struggle to afford advanced training and upskilling opportunities let alone attracting new talent into the sector. The Office should consider training grants, tax relief and/or employer incentives to help engineers invest in their long-term careers. A dedicated funding scheme for small businesses would encourage sole traders and SMEs to train their teams and/or take on career-change employees, increasing skills and diversity in the sector.

5. Defining clear career pathways in clean energy

Heating engineers need a structured career progression route aligned with clean energy targets. The Office should develop a national career roadmap, detailing steps from entry-level qualifications to expert status in heat pump and system efficiency design. This will provide apprentices, engineers and career-change entrants with long-term career visibility.

5. What more can the Department for Energy Security and Net Zero do to ensure the workforce is in place to deliver the Clean Energy Mission and accelerate the retrofitting of homes and businesses?

One critical step the Department for Energy Security and Net Zero (DESNZ) can take is to mandate installation and consumer protection standards beyond the duration of the Boiler Upgrade Scheme (BUS) to ensure long-term quality, accountability and consumer confidence in heat pump installation standards.

1. Make MCS installation standards mandatory for all heat pump installations

Currently, heat pump installers must be MCS-certified to access the Boiler Upgrade Scheme grant, meaning they are required to meet the MCS installation standard. However, this is not a universal requirement, meaning many heat pumps are installed outside of any recognised standard, which risks poor performance and consumer dissatisfaction.

DESNZ should make MCS or an equivalent independent certification scheme mandatory for all heat pump installations beyond the BUS grant. This would ensure consistent system performance, proper commissioning and long-term reliability.

2. Extend consumer protection requirements beyond the grant scheme

Under the BUS, installers must also be members of a consumer protection code, such as RECC (Renewable Energy Consumer Code), which provides homeowners with strong protections against poor workmanship and mis-selling. However, once the grant ends, there is no requirement for installers to adhere to these consumer protection standards.

DESNZ should require all heat pump installers to be part of an approved consumer protection scheme, ensuring customers have recourse in cases of poor workmanship, misrepresentation or unresolved disputes.

6. Summary of actions and impact

1. Mandate hydronics training for all heating engineers

Action: Require Gas Safe engineers to undertake system efficiency training as part of their ACS reassessment every five years to ensure they have the hydronics knowledge necessary to optimise condensing boilers today and transition smoothly to heat pumps in the future.

Impact:

●        Reduces gas use immediately through better boiler efficiency.

●        Prepares engineers for heat pumps without overwhelming them with rapid changes.

●        Helps the UK build a heat pump-ready workforce from the existing heating engineer base.

2. Reform and standardise heat pump training

Action: Conduct a full review of current heat pump training provision and introduce mandatory hydronics training as part of all heat pump certification programs.

Impact:

●        Ensures installers can design and install efficient, well-optimised systems.

●        Increases installer confidence, leading to better consumer experiences and increased uptake of heat pumps.

●        Reduces installation errors that damage the reputation of heat pump technology.

3. Mandate MCS Standards and consumer protection for all heat pump installations

Action: After the Boiler Upgrade Scheme (BUS) ends, mandate MCS installation standards (or an equivalent independent certification scheme) and require all installers to be part of an approved consumer protection scheme (such as RECC).

Impact:

●        Prevents poor installations that undermine consumer confidence.

●        Protects households from substandard work, mis-selling, and poor system design.

●        Ensures all heat pumps meet a high performance standard, reducing energy waste and long-term costs for homeowners.

4. Introduce a National CPD framework for heating engineers

Action: Establish a national CPD requirement for heating engineers to ensure ongoing skill development in clean energy technologies.

Impact:

●        Creates a culture of lifelong learning, boosting workforce competence and confidence.

●        Provides clear career progression opportunities to retain skilled workers.

●        Encourages more heating engineers to specialise in low-carbon heating solutions.

5. Expand Financial Support for Training and Workforce Growth

Action: Offer training grants, tax relief and employer incentives to:

●        Help engineers afford advanced training and upskilling.

●        Support SMEs and sole traders in training staff.

●        Encourage new entrants, including women and career changers, into the heating industry.

Impact:

●        Addresses the 40% retirement rate in the gas workforce over the next decade.

●        Diversifies the workforce by making training more accessible to underrepresented groups.

●        Ensures a stable supply of skilled professionals to meet clean energy targets.

January 2025

8