Energy Saving Trust heat pump field trial
The largest UK monitored study of heat pumps installed in real homes, revealing what good and poor installation actually deliver.
Source
Summarised from Energy Saving Trust, a Tier 2 source on Your Home Climate. We did not run this project; the figures below are reported by them. Click through to verify any of them at the original publication.
https://energysavingtrust.org.uk/report/the-heat-pump-field-trial/The problem
Heat pump performance in laboratory tests differs sharply from performance in real UK homes. Until the EST field trial, the gap was largely anecdotal.
What they did
The Energy Saving Trust monitored a sample of heat pump installations across the UK over multiple heating seasons, measuring electrical input and heat output to derive system efficiency in real homes. Results were published with the variation between sites shown, not averaged into a marketing number.
What the source reports
- Best-installed system efficiency observedAround 3.0 SPFmeasured
- Worst-installed system efficiency observedAround 1.8 SPFmeasured
Measured means monitored data from the site. Reported is the publisher's stated figure. Modelled is a target or design figure rather than an outcome.
What we take from it
- Installer quality and emitter sizing dominate heat pump performance. Brand differences are a rounding error next to design quality.
- A heat pump in a poorly designed system can cost more to run than the gas boiler it replaced.
What the source does not tell us
- The trial is over a decade old. The industry has matured significantly since, but the lesson about installation quality has not changed.