CIBSE’s Technical Director, Dr Anastasia Mylona, recently joined Winifred Robinson on BBC Radio 4’s You and Yours programme to discuss the Institution’s new heat pump factsheet and System Criteria Guide, developed by CIBSE's Domestic Building Services Panel (DBSP) to support homeowners considering a move to low-carbon heating.
The interview explored the growing interest in heat pumps, the complexity of retrofit decisions in existing homes, and the importance of accessing independent, high-quality advice to avoid poor outcomes.
Supporting homeowners through a complex transition
Switching to a heat pump is increasingly seen as one of the most effective ways for households to reduce carbon emissions and lower heating energy demand. However, as Dr Mylona emphasised during the interview, the transition is not a simple like-for-like replacement of a boiler.
A successful installation depends on careful design, correct system sizing, appropriate installation, commissioning, and ongoing operation. Without this, households risk inefficient performance, higher running costs, and potential comfort or moisture issues.
Dr Mylona explained that CIBSE developed its new factsheet in response to growing amounts of information available to consumers, some of which can be confusing or incomplete.
“There is a lot of information, and I’d like to say misinformation, although some of it is useful,” she said. “We tend to concentrate on the negatives and find it difficult to follow the positives. As a technical engineering charity, it is our role to provide the right kind of information for the public.”
The importance of independent expertise
A key message from the interview was the importance of engaging an independent, qualified professional to assess a home before installation. Dr Mylona advised that homeowners should seek advice from a retrofit-focused heat pump engineer who is not tied to a specific manufacturer or installer.
She stressed that a proper assessment should consider the building as a whole, rather than simply determining whether a heat pump can be fitted.
“The key point is that you need somebody that is fiercely independent,” she said. “They need to assess your property as a whole, do a proper sizing, and provide the right advice and system if that is a heat pump.”
CIBSE’s guidance encourages homeowners to look for professionals with relevant expertise through professional bodies or recognised organisations that can provide independent advice.
A holistic approach to retrofit
The interview also highlighted the importance of taking a holistic approach to retrofit. Older buildings, in particular, may have higher heat loss due to limited insulation or less efficient building fabric.
Dr Mylona explained that improving the thermal performance of a home is often a critical first step, as heat pumps operate most efficiently at lower temperatures than traditional heating systems.
“Heat pumps work best when they run on low temperatures,” she noted. “They are not like boilers that just switch on and deliver heat. They perform best when the building retains heat effectively.”
Beyond building fabric improvements, she also emphasised the importance of understanding household needs, including occupancy, hot water usage, and comfort expectations. These factors are essential in ensuring that a system is designed appropriately for the way people actually live in their homes.
Avoiding unintended consequences
The discussion also addressed the risks associated with poorly planned retrofit work. In particular, Dr Mylona warned that inappropriate insulation or ventilation strategies can lead to issues such as damp and mould.
She highlighted the need for a balanced approach that improves energy efficiency while maintaining healthy indoor air quality through appropriate ventilation strategies.
Addressing consumer questions and real-world challenges
The interview also reflected common concerns from households, including the practicalities of funding schemes, property constraints and suitability in specific housing types such as conservation areas.
Dr Mylona encouraged homeowners to start by building a basic understanding of what heat pumps can and cannot do, before seeking expert advice.
She also pointed to independent organisations such as the National Retrofit Hub and Nesta as useful sources of impartial guidance, alongside professional engineering advice.
Empowering better decisions
CIBSE’s new Factsheet and System Criteria Guide aim to give homeowners the tools to ask informed questions when engaging with installers and designers. By improving understanding at the early stages of decision-making, the guidance seeks to support better-designed systems, improved performance, and more successful outcomes.
The resources are intended to empower consumers to take control of their low-carbon journey, ensuring that decisions are based on robust technical understanding rather than marketing claims or fragmented advice.
As Dr Mylona concluded during the interview, informed preparation is key: understanding the system, engaging the right expertise and ensuring the home is properly assessed can make the difference between a successful installation and a problematic one.
CIBSE continues to develop guidance and technical resources to support the transition to low-carbon buildings, helping ensure that the shift to heat pumps is both effective and sustainable.
Listen to Dr. Mylona’s interview on BBC Radio 4 HERE (starting at 36:30).