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The Commissioning Quality Gap

heat pumpscommissioningOEMsperformance gapinstaller trainingMCSSCOP

Public field data shows a wide spread in heat pump performance. The BEIS Electrification of Heat Demonstration Project reported a median seasonal performance factor of 2.80, which is the heat a system delivered over a year divided by the electricity it took to deliver it. Verified installations tracked by Heat Geek report an average SCOP of 4.40, and the open monitoring data published on HeatPumpMonitor.org also sits well above the BEIS median.

Hardware does not explain the distance between 2.80 and 4.40. The same compressor technology, the same refrigerant cycles and the same product lines turn up in both datasets. What differs is how the systems were set up on the day they went in.

Where the performance goes

The root causes are well documented and fairly dull. Flow temperature, the temperature of the water the heat pump sends to the radiators, is often left wherever the factory set it. Weather compensation, the setting that lets a system run cooler when the weather is mild, frequently never gets switched on. Systems are sized for a larger heat loss than the house actually has, so they cycle on and off and wear the compressor out early. Radiators too small for heat pump temperatures force the water hotter than it needs to be, and every extra degree costs efficiency.

None of that is a technology failure. Each one is a commissioning decision, or the absence of one. The Energy Saving Trust reached the same conclusion in its earlier field trial of 83 systems: installation quality was the primary contributor.

For OEMs, the consequence arrives as warranty claims, repeat service visits and reputational damage at the moment the market most needs to scale. It also breaks the continuity between what the designer assumed, what the installer delivered, and what the aftercare team eventually finds.

Why self-reported checklists fail

The Microgeneration Certification Scheme runs on self-certification: installers issue their own MCS certificates. Certification bodies audit periodically, but neither the frequency nor the depth of those audits keeps pace with the growth in installation volumes, and industry reporting has identified cases where the certificate did not match the equipment on the wall.

Benchmark Commissioning provides a paper framework for recording correct setup, and it too relies on the installer to report accurately. There is no independent verification of the data, no cross-reference against how the system actually behaves, and nothing that would detect factory defaults left untouched after the paperwork was signed.

One programme stands apart. Mitsubishi Electric's Diamond Quality Partners scheme requires independent third-party validation, which makes it the closest thing the industry has to governed commissioning verification. It works through periodic physical inspection rather than continuous analysis of the data those systems are already producing.

What 48 hours would change

Consider what changes if a manufacturer can tell, within 48 hours of installation, whether the job was commissioned properly.

A connected heat pump starts producing evidence in its first hours of operation: the temperature of the water going out and coming back, how often the compressor starts and stops, how often it defrosts, how much heat it delivers for the weather outside. Set against what that property ought to produce in those conditions, that is enough to separate a system that was properly set up from one left on defaults with weather compensation disabled.

The money follows quickly. A single warranty callout typically costs between 200 and 400 pounds, and when the underlying cause is an undetected commissioning error, the same unit generates repeat visits for the rest of the warranty period. On a fleet of 10,000 connected units, a conservative 15 per cent carrying commissioning issues comes to over half a million pounds of annual warranty exposure.

Detection that early also changes what a manufacturer can say to its installer network. Specific, data-backed feedback in the first week reads as help. A generic audit finding six months later reads as an accusation.

Regulatory pressure is building

The Clean Heat Market Mechanism obliges boiler manufacturers to deliver heat pump credits, which pushes installation volumes up. Scaling volume through an installer base that is itself scaling compounds the quality risk: the Heat Pump Association reported in November 2024 that 39 per cent of those who complete heat pump training never go on to install one. Experienced and inexperienced installers work side by side, and nothing systematically distinguishes the quality of their work.

The Future Homes Standard will add to that pressure, requiring newly built homes to produce at least 75 per cent lower CO2 emissions, with heat pumps as the primary compliance technology. At that point, verifying performance at commissioning stops being a way to stand out and becomes something the rules expect.

What verification looks like when it works

Governed commissioning verification replaces the self-reported checklist with an evidence trail built from how the system actually behaves, starting in its first hours. Each assessment is recorded with what it looked at, what it found and what it recommends, so there is an unbroken account running from installation through to how the system performs a year later.

That account is worth something to several people at once: the OEM service team deciding whether a callout is a product fault, the installer who would rather fix the thing than argue about it, and the certification body. Across a network it also shows which installers need support, and where that support would do the most good.

The commissioning quality gap is systemic, and systemic problems do not yield to individual audits, because there are never enough auditors. Self-certification has demonstrable limits. What closes the gap between what the technology can deliver and what installations achieve is evidence that keeps up with the work: drawn from operational data, attached to the home, and still there through commissioning, service and aftercare.

Aeterno builds commissioning verification and performance assurance for heat pump manufacturers. The platform sits alongside the connected product ecosystems that already exist, picks up commissioning issues in the first days of operation rather than in the first winter, and leaves behind the evidence that warranty management, installer development and regulatory compliance all turn out to need.

Source notes

  • BEIS Electrification of Heat Demonstration Project
  • Energy Saving Trust domestic heat pump field trials
  • Heat Geek verified installation data (source of the 4.40 average SCOP)
  • HeatPumpMonitor.org public monitoring data
  • Heat Pump Association workforce and market reporting
  • MCS certification framework and Clean Heat Market Mechanism policy materials

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