Il be listening in on this one this evening (in less than an hours time) 6pm
Colin Meek of RB&M will be presenting his latest work on UK in-situ heat pump performance. Colin’s review of the latest Ofgem Data (2017–2022) is currently pending publication by DESNZ and follows on from his previous analysis of domestic installations in over 2,000 homes (2021).
The presentation by Colin Meek was very interesting. He will be publishing soon the results of his latest review of Ofgem data from 2017-2022. It’s surprising how low these wider study results continue to be… SPF’s around 2.7… I’m scratching my head a bit TBH!
Here’s the ASHP chart from Colin’s 2021 study:
Colin made some important points about terminology:
I think most of us using SCOP mean measured performance but others might think we are referring to forecasted performance by the installer or manufacturer which can obviously be quite different . I’ve never been one to be concerned about terminology but it’s probably better that we adhere to the standard use of these terms at least in the way they are use in industry technical literature.
I think the study results that Colin presents highlights the importance of what we (in a collective sense of everyone contributing) are doing with HeatpumpMonitor.org. Our results demonstrate that good installations can achieve much better results. Without that we’d have to settle with the results form these trials and it would be harder to see a path to higher performance or perhaps less abstractly, running costs lower than gas. The big question is why is there such a big difference?
Anecdotally, two out of four friends/family with heat pumps have them programmed like a gas boiler, only coming on at full blast 50C+ flow temp for a couple of hours in the morning and evening. All have buffers, extra pumps, multiple zones.
It’s going to take a while to shift consumer and installer mindsets.
This is a really important point and runs the risk of giving heat pumps a bad reputation, when they struggle to deliver the heat required to quickly bring a house up to temperature - and taking a big hit on efficiency when trying to achieve the target.
It’s the strong relationship between flow temperature and efficiency that is so different to a gas boiler, meaning it’s better to keep the heating on all the time than to run in short bursts - but it’s counter-intuitive to expect to save money by heating a house when nobody is home (especially when third-party controllers like Hive are marketed on the basis of dynamic scheduling).
There’s some good research in this Passivhaus Trust paper: Research Report - The right time for heat pumps in retrofit - see “INSULATION LEVEL AND CONTINUOUS VS INTERMITTENT HEATING” starting on Page 8 and especially “HEATING ON A BUDGET – INTERMITTENT VS CONTINUOUS OPERATION OF ASHP” on Page 13.