The Commissioning Quality Gap

Public field data shows a wide spread in heat pump performance. The 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, and the spread within that trial ran from systems that would flatter any brochure to systems costing their owners real money every winter. The Energy Saving Trust reached the plainest conclusion in its own field trial of 83 systems: installation quality was the primary contributor.

The same compressor technology, the same refrigerant cycles and the same product lines appear at both ends of the spread. What differs, home by home, is how well the delivered system matches what its design promised: the sizing, the settings, the emitters it was asked to work through, and the fabric around them.

The question nobody can currently answer

Ask a simple question of almost any installed base: which of these systems was delivered right?

Today there is no record that answers it. The delivered system either matches its design or it does not, and the difference is worth thousands of pounds across a warranty life, yet the moment that decides it, commissioning day, leaves almost no evidence behind. What it leaves is paperwork.

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 cannot close it

The Microgeneration Certification Scheme runs on self-certification: installers issue their own MCS certificates, and certification bodies audit periodically. The limit is structural rather than personal. Audit frequency and depth cannot keep pace with installation volumes that policy is deliberately pushing up, and a checklist completed on the day records intentions, not outcomes.

Benchmark commissioning records that setup was done. It cannot record whether the system then behaves the way that setup promised, because the evidence for that only exists once the system runs.

None of this is an argument against installers. Most installs are sound, and the people who did them currently have no way to prove it. A record that verifies delivery cuts both ways, and the commonest thing it will do is clear the person who did the work.

What the first 48 hours can say

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 home was designed to receive in those conditions, that is enough to separate a system delivering its promise from one that is not, and enough to say why on evidence rather than suspicion.

Where the shortfall traces to the design, the record says so, and the installer who fitted it is cleared. Where it traces to a setting, the fix is named while the van is still in the area. Where the work was right, the record says that too, which is the sentence self-certification could never carry.

Timing changes the relationship. Specific, evidence-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 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, so experienced and inexperienced hands work side by side with nothing recording the difference in what they deliver.

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

What closes the gap

The commissioning quality gap is systemic, and systemic problems do not yield to individual audits, because there are never enough auditors. What closes the gap is a record that keeps up with the work: the design promise recorded before install day, the delivered system checked against it from its first hours, and the account still there through service, aftercare and every later conversation about whose promise held.

That is the record HeatAssure keeps. Each home's design promise, its commissioning evidence and its delivered performance sit in one account, kept and governed by Aeterno, so the OEM service team can tell a product question from a delivery question, the installer can point to verified work instead of arguing, and support goes where the evidence says it is needed.

Source notes

• Electrification of Heat demonstration project: median seasonal performance factor 2.80, with the spread reported within the trial
• Energy Saving Trust domestic heat pump field trials: installation quality identified as the primary contributor
• Heat Pump Association workforce and market reporting, November 2024
• MCS certification framework and Clean Heat Market Mechanism policy materials

Next steps

• HeatAssure: the record each home is held to
• For Heat Pump OEMs: how Aeterno works with heat pump manufacturers
• Talk to us if commissioning quality is already visible in your callback and warranty numbers