Audits for Heat Pump Homes

A heat pump audit differs from a boiler audit because heat pumps work best at low flow temperatures, over long running periods, with emitters sized for those temperatures, while boilers traditionally work at higher temperatures with shorter, hotter cycles. An audit should therefore check heat loss, emitter sizes, flow temperature settings, control strategy, defrost and outdoor unit placement, and hot water arrangements, all through a low-temperature lens. A heat pump fitted to a high-temperature radiator system, without emitter or control changes, will struggle, however good its specification.

Heat pump audits also need to check expectations. A heat pump home feels different from a boiler home: radiators feel warm rather than hot, heating runs longer at lower output, and setback temperatures matter more, because reheating a cold home with a heat pump takes longer. An audit should explain those differences to occupants, so normal low-temperature operation is not mistaken for failure, and genuine faults, such as short-cycling or high flow temperatures, are recognised.

Flow temperature is the central audit figure: what temperature water leaves the heat pump, under what outdoor conditions, and whether weather compensation adjusts it automatically. A system running at high flow temperatures year-round, regardless of weather, is losing efficiency and may indicate oversized emitters, poor controls, or a design that did not account for low-temperature operation. An auditor will note flow temperatures, weather compensation settings, and whether occupants have altered them.

Emitter checks follow: radiator sizes relative to room heat loss at low flow temperatures, underfloor circuit presence and zoning, and any fan-assisted radiators or upgraded emitters fitted for heat pump use. A room with radiators sized for a boiler at high temperature may need larger radiators, additional emitters, or underfloor heating to deliver enough heat at low temperature, and an audit should identify those rooms specifically, rather than recommending a blanket emitter upgrade.

Gather heat pump records before the audit: installation certificate, MCS documentation where applicable, heat loss calculation, emitter schedule, control manuals, servicing history, and any monitoring data on flow temperatures, running hours and electricity use. Note rooms that struggle in cold weather, noise concerns, defrost behaviour, and hot water performance, because those symptoms point to specific audit checks.

Check controls and occupant use: is weather compensation enabled, are thermostats set for steady temperatures rather than large setbacks, and are radiator valves open where needed? Heat pump controls reward steady, low-temperature operation and penalise frequent on-off cycling, so occupant habits formed with a boiler may need adjustment, and an audit should include control instruction as a finding, not just a footnote.

In the UK, heat pump audits and designs follow MCS standards where certification applies, with heat loss calculations, emitter sizing, and commissioning requirements specific to heat pumps. A UK homeowner should check MCS documentation and installer accreditation for their system, and should expect an audit to reference those standards, rather than generic boiler audit practice.

In EU member states, heat pump practice varies with climate and market maturity: Nordic countries have long heat pump traditions with low-temperature emitter design as standard, while Southern European countries use heat pumps more for cooling as well as heating, with different control and sizing traditions. A homeowner abroad should check national heat pump design standards and installer qualifications for their climate and system type.

One heat pump mistake is auditing or replacing a heat pump without checking fabric first. A leaky home needs high flow temperatures to stay warm, which erodes heat pump efficiency, while an insulated home allows low flow temperatures and efficient operation. Fabric findings should therefore precede or accompany heat pump audit conclusions, and a heat pump audit that ignores fabric will misdiagnose efficiency problems as equipment faults.

Another mistake is judging a heat pump by radiator temperature alone. Warm radiators are normal at low flow temperatures, and a system delivering steady comfort at low temperature is succeeding, even if radiators never feel hot. Judging by comfort, running hours, flow temperature and electricity use together, rather than by touch alone, prevents unnecessary equipment replacement for normal low-temperature behaviour.

Keep heat pump installation and MCS records, heat loss calculations, emitter schedules, control settings, servicing records, and monitoring data, with the audit report. That file allows future installers to service, resize or upgrade correctly, and it supports warranty, grant and sale evidence where applicable.

Ask an auditor what flow temperatures the system runs at, whether emitters suit low-temperature operation room by room, and what control changes would improve efficiency. Ask also whether fabric work would allow lower flow temperatures, and what that would mean for efficiency and comfort. Those answers link heat pump performance to the home, not just to the unit.