MEMBER BLOG: Hermione Crease, Purrmetrix, on BPE and the Heat Pump Ready programme

Heat pump ready – Improving tests for householders and heat pump installers.

The UK has huge ambitions for heat pump roll out with targets of 300,000 per year by 2030. They are a key part of the plan to decarbonise heating in homes and moving to electrical heating will also make the UK more energy independent. But the technology faces formidable barriers, including bottlenecks in the supply chain and substantial capital costs required to transition homes from gas to heat pumps.

The right approach building performance evaluation can reduce these barriers. For heat pump designers and installers in the market at the moment, surveying potential sites and calculating system sizes is complex, time consuming and manual.

It’s also full of uncertainty, where installers find it hard to identify building materials and the state of the fabric. In those situations, installers tend to size up systems, and this drives up costs both in initial outlay and in running the heat pump. Progress has been made in automating some of the survey tools, but a more data-led approach to measuring the true performance of homes has great potential to scale up an installers’ operations and increase consumer satisfaction.

To investigate this, BPN Members Purrmetrix and Hoare Lea have been funded by BEIS to develop testing tools for the heat pump market that offer the potential to slash survey times, deliver more robust calculations, and help optimise the performance of the heat pump system as it is installed.

As part of the DESNZ Heat Pump Ready funding programme (which supports the development of tools, technologies and processes that can overcome the bottlenecks in the market) we are working on a set of automated tests that can measure heat loss for the home overall, confirm if radiators in each room are heat pump ready and identify the most suitable products and operating envelope for a heat pump install.

The work – with long term partners and data scientists City Science – is extending an earlier solution that provides heat loss calculations for retrofit projects. The software relies on collecting temperature and energy data from each home, using Purrmetrix portable Warmscore toolkit. A few weeks of this data gives a full heat loss for the home and this helps select appropriate products and operating envelope for them.

The test will also use data from each room to confirm if the radiators will succeed in warming a room when operated at lower flow temperatures, as usually provided by heat pumps. Replacing radiators is often a major expense in heat pump installs and can be very disruptive, so the goal is to make sure this is only done when strictly needed.

Over the winter the consortium has completed a first round of testing and work to build prototypes for the testing system, using data gathered from multiple test sites. We are now looking forward to further testing in the last two quarters of the year, and hoping to open up conversations with heat pump installers and designers who might be interested in testing out these products. If that’s you, please get in touch with

Example output from Purrmetrix’s monitoring.