Thousands of households with heat pumps could be paying more than they should to heat their homes because of a hidden issue in how the systems are installed.
New figures presented at a CIBSE Decarbonisation Conference in London suggest that poorly insulated external pipework could be costing some homes around £74 a year in wasted energy.
The findings point to installation quality as a key factor affecting how well the technology performs in real homes.
What the £74 figure is based on
The estimate is based on modelling of heat loss from external pipework where insulation is missing, damaged or poorly fitted.
Even small gaps in insulation can allow heat to escape before it reaches the home, reducing efficiency and increasing running costs.
Across affected households, national energy service WattsWatt estimates this could amount to around £20 million a year in wasted energy.
What experts said at the conference
The issue was highlighted at the CIBSE Decarbonisation Conference in London, which was attended by leading industry and policy figures.
Lisa Malyon, co-founder and CEO of WattsWatt, told the Conference in London that poor insulation on external pipework can drastically affect how efficiently heat pumps operate.
“It’s quite straightforward – if your external pipes aren’t insulated properly, the water cools as it travels through these outdoor pipes, affecting the temperature inside the house. To get the house back up to temperature, the heat pump has to work harder, which uses more energy,” she said.
She added that issues are often only identified after the heat pump installation.
“We first became aware of the issue when households complained their heat pump had stopped working – saying it was nowhere near as good as it had been when it was first installed. It turns out, their external pipework had been insulated with basic grey insulation designed for inside – and it was soaked through.”
Professor Richard Fitton, Professor of Building Performance at the University of Salford, said: “Heat pump technologies need careful design and installation for optimum performance.”
What should affected homeowners do next?
If homeowners suspect their heat pump is not performing properly due to insulation or installation issues, TrustMark – the government-endorsed quality scheme for home improvements – advises that the first step is to contact the original installer.
Most accredited Microgeneration Certification Scheme installations are covered by warranties and consumer protection arrangements, meaning faults may be assessed and corrected without additional cost if raised early.
For homeowners, signs of a potential problem can include:
- Higher than expected running costs
- Reduced heating performance compared to early use
- Visible or poorly protected external pipework
If the installer does not resolve the issue, homeowners can escalate the complaint through TrustMark’s approved dispute resolution process, which is designed to handle problems with certified work.
Homeowners are also advised to keep any paperwork, installation details and records of communication, as this can help support a complaint if further action is needed.
