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What Should an Independent Heat Pump Inspection and Report Check?
How design, sizing, radiators, pipework, controls, commissioning and performance should be assessed.
- Last updated: September 2026
- Heat Loss Hub · Homeowner Advice
A heat pump can be mechanically healthy while the wider heating system is poorly designed, incorrectly installed or badly commissioned.
That is why a proper independent heat-pump inspection should involve much more than checking whether the outdoor unit switches on and looking for fault codes.
A useful inspection should establish what the system was designed to achieve, what equipment was actually installed, whether heat can be moved and delivered around the property, how the system was commissioned and controlled, how it is actually performing, and what the available evidence shows needs attention.
KEY TAKEAWAY
This guide explains what a thorough independent inspection of an existing installed heat-pump system should cover. It is not a pre-installation heat-pump survey, an annual service checklist or a specialist installer-dispute report.
What Should a Good Heat Pump Inspection Cover?
A comprehensive inspection can be considered across six areas.
1. Design
Was the original heating requirement calculated correctly and was an appropriate system designed?
2. Equipment
Were the heat pump, emitters, cylinder and other major components correctly selected?
3. Heat Delivery
Can the pipework, pumps and emitters move and release the required amount of heat?
4. Commissioning and Controls
Was the completed system set up to operate as the design intended?
5. Actual Performance
Does the system maintain the expected room temperatures and operate sensibly in real conditions?
6. Report and Recommendations
What does the evidence show, what could not be confirmed and what should happen next?
A useful independent inspection should connect all six.
Start With the Reason for the Inspection
Not every heat-pump inspection needs the same level of investigation. The scope should reflect the problem.
One Room Is Always Cold
The priority may be: room heat loss → radiator or UFH output → local water flow → balancing → controls.
The Whole House Struggles to Get Warm
The inspection may need to look much more broadly at: building heat loss → heat-pump capacity → flow temperature → hydraulics → emitters → commissioning.
Electricity Use Is Much Higher Than Expected
Priorities may include: heat demand → flow temperature → hot water → immersion/backup heating → cycling → controls.
You Want a General Second Opinion
A broader review of design, installed equipment, commissioning and current operation may be appropriate.
You Are Buying a Property With a Heat Pump
The emphasis may be on design documentation, equipment age and condition, obvious system-design issues, current settings, servicing, and likely remedial risks.
You Are Already in a Dispute With the Installer
A normal inspection may not be enough. A dispute report usually requires a more formal evidence trail, chronology, document review and clearly structured technical findings.
See our Independent Heat Pump Report for Installer Disputes.
Is an Independent Inspection the Same as a Heat Pump Service?
No. There can be some overlap, but they serve different purposes.
A Heat Pump Service
A routine service is primarily concerned with the condition and maintenance of the equipment. This may include checking for faults, filters and strainers, visual condition, pressures where applicable, general operating checks, and cleaning or maintenance tasks.
An Independent Heat Pump Inspection
A broader independent assessment may also consider heat-loss calculation, heat-pump sizing, radiator and UFH sizing, design flow temperature, pipework, water flow, balancing, controls, commissioning, and real-world system performance.
KEY TAKEAWAY
This distinction is important. A service engineer can legitimately conclude “the heat pump itself is operating normally” while the overall heating system may still have a design, distribution or commissioning problem.
Is an Inspection the Same as a Pre-Installation Survey?
No.
A pre-installation survey gathers information about the property so that a new heat-pump system can be designed.
An independent post-install inspection evaluates a system that already exists. It asks: was the system appropriately designed, does the installation match that design, and is the completed system performing as intended?
Step 1 — Review the Original Design Documents
A good inspection should ideally begin before looking at the equipment. First establish what the system was supposed to achieve.
Useful documents include room-by-room heat-loss calculation, whole-house heat loss, design internal temperatures, outdoor design temperature, design flow temperature, radiator or emitter schedule, exact heat-pump make and model, manufacturer performance data, hydraulic schematic, cylinder specification, performance estimate, commissioning documents, and handover information.
Without the design, it is much harder to judge whether the installation is performing as intended.
Step 2 — Does the Heat-Loss Calculation Look Credible?
A report should not simply accept “heat loss = 8.7kW” without considering where the number came from.
Where relevant, the original calculation may need to be reviewed for room dimensions, external wall areas, wall construction, insulation, roof or loft construction, floor construction, windows and doors, ventilation, airtightness assumptions, internal temperatures, and outdoor design conditions.
An inspection may identify that the existing calculation appears reasonable. It may instead identify questionable assumptions. Or there may not be enough evidence to reach a conclusion.
A full independent room-by-room recalculation is a separate level of work and may be recommended where the original heat-loss calculation is central to the problem.
Step 3 — Was the Heat Pump Correctly Sized?
Heat-pump sizing cannot be checked simply by comparing house heat loss = 8kW with heat-pump model = 8kW.
The correct comparison is between credible building heat demand and actual output available from the exact heat-pump model at the relevant outdoor and water temperatures.
The inspection should consider both ends of the operating range.
Maximum Capacity
Can the heat pump provide enough heat when the property demand is highest?
Minimum / Modulating Capacity
Can it reduce its output sufficiently as the building demand falls? A unit may be capable of meeting the cold-weather load but still cycle excessively in milder weather if its minimum output is too high for the active load.
If sizing is the main concern, see our Independent Heat Pump Sizing Review.
Step 4 — Are the Radiators or Underfloor Heating Correctly Sized?
Correct whole-house heat-pump sizing does not guarantee that every room can get warm. Individual room heat losses need to be compared with the heat available from the emitters.
The inspection may therefore consider room heat loss against specified radiator or UFH output and actual installed emitter at the relevant design temperatures.
For example: room requirement 1,300W; original radiator selection sufficient at the design temperature; installed radiator materially smaller.
That may explain why one room underperforms even if the heat pump itself is correctly sized.
Step 5 — Does the Installed System Match the Design?
A useful inspection should compare documentation with reality.
| Design item | What should be checked |
|---|---|
| Heat pump | Is the specified make/model installed? |
| Radiators | Do sizes and types match the emitter schedule? |
| UFH | Does the available evidence match the intended layout? |
| Cylinder | Is the specified type and capacity installed? |
| Pumps | Does the arrangement match the design? |
| Valves | Are relevant components present and configured? |
| Buffer/volumiser | Does it match the hydraulic design? |
| Controls | Were the intended controls fitted? |
| Pipework | Do visible/documented routes and sizes appear consistent with the design? |
A different component is not automatically wrong. The question is whether the substitution is technically suitable.
The Produce → Move → Emit → Control Test
One of the simplest ways to assess a heat-pump system is to break heat delivery into four stages.
Produce
Can the heat pump generate enough heat?
Move
Can the pipework and pumps move that heat around the heating system?
Emit
Can the radiators or UFH release enough heat into each room?
Control
Are the controls allowing the first three stages to work properly?
A failure at any one stage can create poor comfort. That is why checking only the outdoor unit is not enough.
Step 6 — Check the Primary Pipework and Hydraulics
The heat produced by the heat pump needs to reach the emitters.
The inspection should therefore consider visible and documented aspects such as primary pipe sizes, pipe routes, obvious restrictions, circulation pumps, valves, bypass arrangements, strainers, filters, air removal, hydraulic separation, and insulation.
Pipework should be assessed against the flow the system requires. Statements such as “15mm pipe is always wrong on a heat pump” are too simplistic. Pipe length, required flow, pressure loss, fittings and system configuration all matter.
Concealed pipework may not be possible to verify without drawings, photographs or more invasive investigation. That limitation should be stated.
Step 7 — Check System Water Flow
Even a correctly sized heat pump cannot transfer its intended output if insufficient water is moving through the system.
Where possible, the inspection should consider required flow rate, manufacturer minimum or design requirements, actual or reported system flow, pump capability, and observed system behaviour.
Flow and return temperatures can also provide useful information. But there is no single universal temperature difference that proves every heat-pump system is operating correctly. The values need to be interpreted in context.
Step 8 — Check Hydraulic Balancing
A system can have enough total heat available but distribute it badly.
Possible signs include radiators near the heat pump becoming much hotter than distant ones, upstairs warm while downstairs struggles, one pipework branch consistently underperforming, or UFH loops receiving very different flow.
This can indicate a distribution problem rather than insufficient heat-pump capacity. A useful inspection should distinguish between the two.
Step 9 — Check Pumps, Buffers and Hydraulic Separation
If the system contains additional pumps, buffers, volumisers or hydraulic separation, the inspection should establish why they are there and how they operate.
Questions may include: is the component providing additional system volume? Is it providing hydraulic separation? Are there primary and secondary pumps? Could mixing be reducing the temperature reaching the emitters? Does the arrangement match the original design? Is adequate active system volume available when zones close?
A buffer tank should not simply be recorded as “present — pass.” Its purpose and effect on the system matter.
Step 10 — Compare Design Flow Temperature With Actual Operation
Design flow temperature is one of the most useful checkpoints in a heat-pump assessment.
Suppose the original design states 42°C flow temperature at the design condition, but the property only becomes comfortable when the system is increased to 55°C.
That discrepancy deserves investigation. Possible reasons include radiator sizing, room heat-loss assumptions, inadequate water flow, commissioning, control settings, or installed components differing from design.
A higher operating temperature does not automatically identify the cause. But it gives the inspector something specific to investigate.
Target Flow Temperature vs Actual Flow Temperature
This is another useful distinction.
Target = 45°C, Actual = 45°C, House Still Cold
The heat pump is apparently reaching the requested temperature. Look more closely at emitters, water distribution, building heat loss, and system design.
Target = 45°C, Actual = 36°C, House Cold
Now the investigation changes. Possible areas include heat-pump output, water flow, equipment operation, controls, and faults.
The same comfort problem can therefore point to very different technical causes.
Step 11 — Review Weather Compensation and Controls
Controls can make a technically capable heating system perform badly.
A proper inspection may therefore look at whether weather compensation is enabled, current heating curve, maximum flow-temperature settings, thermostat location, heating schedules, setbacks, zoning, TRVs, UFH controls, third-party controls, and DHW priority.
This does not mean there is one correct setting for every property. The controls need to suit the design of the particular heating system.
Step 12 — Check Cycling and Modulation
The inspector should consider how the heat pump actually runs. Does it operate steadily for long periods, or repeatedly start and stop?
Potential causes of repeated cycling include oversized heat pump, high minimum output, excessive zoning, low active system volume, unsuitable controls, and high operating temperature.
There is no universal number of starts per hour that proves a system is incorrectly designed. The operating conditions and equipment characteristics need to be considered.
Step 13 — Check the Domestic Hot-Water System
The inspection should not stop at space heating.
Where relevant, check cylinder make and model, cylinder capacity, suitability for heat-pump operation, DHW target temperature, schedule, reheat behaviour, immersion heater, DHW priority, visible primary pipework, and insulation.
A system can perform well for space heating but poorly for hot water, or vice versa.
Step 14 — Check Immersion and Backup Heating
Direct-electric heating can materially affect electricity use. It is important to distinguish between:
Cylinder Immersion
Used for domestic hot water.
Supplementary Space Heating
Used to support the heat pump under particular conditions.
The inspection should ask: is it enabled? Does it operate? When? Why? Is that operation expected by the design?
The presence of direct-electric heating is not automatically a fault. Unexpected or excessive operation may deserve further investigation.
Step 15 — Inspect the Outdoor Unit
The outdoor unit still needs checking. Relevant items may include airflow, clearances, base/support, vibration, visible damage, debris, access for servicing, condensate and defrost-water drainage, external pipe insulation, and obvious noise or siting concerns.
KEY TAKEAWAY
The outdoor unit is only one part of the heating system. A neat, fault-free heat pump does not prove the whole system is correctly designed.
Step 16 — Check External Pipework and Insulation
Where heating water travels between the outdoor unit and the building, external pipework should be appropriately insulated and protected.
Look for damaged insulation, exposed fittings, poorly insulated valves, gaps around building penetrations, and long exposed runs.
Heat lost from primary pipework has already been paid for by the heat pump. Poor insulation can therefore affect both comfort and efficiency.
Step 17 — Review the Commissioning Evidence
Commissioning is where the completed system should be set up to operate as the design intended.
Available records may include system flow, balancing, heating flow temperature, weather-compensation settings, pump configuration, controller settings, and commissioning date.
The useful question is not simply “is there a commissioning sheet?” It is: does the available commissioning evidence demonstrate that the installed system can achieve the operating requirements the design depends upon?
If important information is missing, the report should say so.
Step 18 — Review Handover and Homeowner Controls
A technically sound system can also perform badly after poor handover.
Consider whether manuals were provided, controls were explained, intended heating strategy was explained, weather compensation was discussed, DHW operation was explained, backup or boost functions were explained, and settings have since been altered.
This helps distinguish between poor original design and a good system no longer operating with its intended settings.
Step 19 — Assess Actual Performance
Where relevant, a thorough inspection should look at how the system behaves in reality.
Useful evidence can include room temperatures, outdoor temperature, flow temperature, return temperature, runtime, compressor starts, error history, backup-heater use, electricity consumption, heat-meter information, and manufacturer-app data.
A report becomes much more useful when it can compare what the design says should happen with what the system is actually doing.
Check Comfort Room by Room
A statement such as “the house doesn’t get warm” can be made much more useful by recording which rooms are affected, target temperature, actual temperature, outdoor temperature, whether the problem happens all winter or only during colder weather, and how the rest of the property behaves.
One cold bedroom and a whole property losing temperature point towards very different investigations.
Check Electricity and Efficiency Where Relevant
Not every inspection needs a full energy-performance assessment. But where high consumption is part of the problem, consider heat-pump electricity, whole-house electricity, space heating, hot water, immersion, backup heating, flow temperature, and cycling.
Be careful with manufacturer app figures. Some values may be measured while others are calculated. A credible COP or seasonal-performance figure requires both useful heat output and electrical input over a clearly understood measurement boundary.
See “Heat Pump Using Too Much Electricity — Could the Design Be Wrong?” for the detailed diagnostic pathway.
Design Value → Installed Value → Operating Value
A useful inspection report should allow these three things to be compared.
| Item | Original design | Installed system | Current operation |
|---|---|---|---|
| Heat pump | Model selected | Model fitted | Output/behaviour |
| Flow temperature | Design temperature | Controller/system capability | Temperature actually required |
| Living-room radiator | Specified size/type | Fitted size/type | Room comfort |
| System flow | Required flow | Pipework/pump arrangement | Measured/reported flow |
| Controls | Intended strategy | Controls fitted | Current settings |
This is much more informative than simply giving every item a tick or cross.
What Can an Independent Heat Pump Inspection Not Automatically Check?
A heat-pump system inspection has limits. It is not automatically an electrical installation condition report, an invasive concealed-pipework investigation, a structural survey, a refrigerant charge assessment, a refrigerant leak test, or a formal acoustic assessment.
Depending on the problem, another specialist may be required. For example: electrical concern → suitably qualified electrical professional. Suspected refrigerant-system problem → appropriately qualified refrigeration engineer. Structural issue → relevant building professional.
A good independent report should recognise where its own scope ends.
What Should Be Recorded During the Inspection?
Where relevant, useful evidence includes heat-pump model plate, cylinder model, radiator sizes, controller screenshots, weather-compensation settings, pump settings, room temperatures, flow/return temperatures, system-flow readings, photographs, visible pipework, buffer/volumiser configuration, documents reviewed, and performance information.
This gives the report an evidence trail rather than relying on memory or general impressions.
How Should Findings Be Classified?
A useful inspection report should not force every item into pass or fail. More useful categories may include:
No Material Concern Identified
Nothing significant was identified from the available evidence.
Optimisation or Recommissioning Required
The design may be fundamentally sound but the system needs setting up differently.
Remedial Work Indicated
A physical installation issue appears to require correction.
Further Investigation Required
There is evidence of a possible problem but additional testing is needed.
Unable to Conclude
Insufficient evidence is available to reach a reliable technical conclusion.
This is more informative than a simple traffic-light checklist.
What Should the Written Inspection Report Contain?
A useful written report should normally explain more than what was visually observed. Depending on scope, it may include:
Reason for inspection — why the assessment was requested.
System details — heat pump, cylinder, emitters and key controls.
Documents reviewed — what design and commissioning information was available.
Design basis — heat loss, sizing and design flow temperature where relevant.
Physical inspection — what was observed.
Design vs installed comparison — material differences.
Commissioning and controls — available evidence and current setup.
Performance evidence — where relevant.
Technical findings — what has actually been identified.
Significance — why each finding matters.
Limitations — what could not be inspected or confirmed.
Recommendations — recommissioning, testing, recalculation or remedial work.
Supporting evidence — photographs, measurements and calculations where appropriate.
A Good Report Should Explain Why Each Finding Matters
For example.
Finding: the living-room radiator does not match the original emitter schedule.
Evidence: the design specifies a 1400 × 600mm Type 22 radiator. The installed radiator is a 1000 × 600mm Type 21.
Significance: the installed emitter appears to provide materially less output at the documented design conditions.
Next step: confirm the exact radiator output and compare it with the room heat-loss requirement.
That is far more useful than “radiators — fail.”
Has the System Changed Since It Was Installed?
This can be very important.
Ask whether anyone has replaced radiators, altered the heating curve, changed thermostats, added zoning, removed or added a buffer, altered pumps, replaced controls, changed pipework, extended the property, or started heating previously unused rooms.
The system inspected today may not be the system that was originally designed. The report should distinguish the two where possible.
What Should Be Prioritised for Different Problems?
One Cold Room
Prioritise: room heat loss → emitter → local flow → balancing → controls.
Whole House Cold
Prioritise: heat loss → heat-pump capacity → flow temperature → system flow → emitters → controls.
High Electricity Consumption
Prioritise: heat demand → flow temperature → DHW → immersion/backup → cycling → controls.
Frequent Cycling
Prioritise: sizing → minimum modulation → zoning → system volume → controls.
Hot-Water Problems
Prioritise: cylinder → DHW controls → reheat strategy → immersion → heat-pump operation.
Installer Dispute
A more formal evidential assessment may be required. See Independent Heat Pump Report for Installer Disputes.
Buying a House With an Existing Heat Pump
An independent inspection can also be useful before buying a property with an existing heat-pump installation.
Useful areas to review include available design documentation, heat-pump make, model and age, heat-loss information, radiator design, system controls, servicing history, current operating settings, commissioning documentation, obvious installation issues, performance evidence, and likely remedial work.
The purpose is not to guarantee future performance. It is to identify obvious technical concerns and areas that deserve further investigation before or after purchase.
Which Heat Loss Hub Service Do I Need?
I Want to Know Why My Existing Heat Pump Is Performing Badly
Choose an Independent Heat Pump Performance Review. This is the broader diagnostic service for an installed system where the cause is not yet clear.
I Specifically Question the Original Heat-Loss Calculation
Choose an Independent Heat Loss Report.
I Specifically Question the Heat-Pump Size
Choose an Independent Heat Pump Sizing Review.
I Need Written Evidence for an Installer Complaint or Dispute
Choose an Independent Heat Pump Report for Installer Disputes. That service adds a more formal evidence structure around the technical findings.
Frequently Asked Questions
Depending on the problem, it may review heat loss, heat-pump sizing, radiators or UFH, pipework, hydraulics, controls, commissioning, domestic hot water, installed equipment, and actual performance. A thorough inspection should look at the complete heating system rather than only the outdoor unit.
No. A service primarily checks equipment condition and maintenance. An independent system inspection can also assess whether the system was appropriately designed, installed and commissioned.
Yes, where heat loss is relevant to the problem. This may involve reviewing the original calculation or recommending a new independent calculation where necessary.
Yes, particularly where rooms are cold or the system requires unexpectedly high flow temperatures. Radiator output should be considered against room heat loss at the relevant operating temperature.
Yes, where relevant. A heat pump can have sufficient capacity but still perform poorly if the heating system cannot move enough water or distribute heat effectively.
Yes. Commissioning is essential because it sets up flow, balancing, controls and operating temperatures. The inspection should consider whether the available evidence shows that the system was commissioned to meet the original design requirements.
Yes, where it forms part of the control strategy. The inspector should assess whether the system’s settings are appropriate for the property rather than applying a universal heating curve.
It can identify evidence that may support or contradict an oversizing concern. This may require reviewing building heat demand, exact heat-pump model, maximum output, minimum output, and cycling behaviour.
Yes. The investigation may include heat demand, flow temperature, hot water, immersion, backup heating, cycling, controls, and actual electricity consumption.
Not always. Some design or documentation issues can be investigated remotely. Physical inspection becomes more important where the installed equipment, pipework, controls or condition of the system need verification.
Some assessments can. A remote review may use original designs, photographs, videos and controller screenshots. The report should clearly state which conclusions are based on supplied evidence rather than direct inspection.
Not automatically. A whole-system heating inspection may note visible electrical information, but formal electrical testing should be undertaken by someone appropriately competent for that work.
Not automatically. Where a refrigeration-system fault is suspected, an appropriately qualified refrigeration engineer may be required.
At minimum, a useful report should identify what was inspected, what documents were reviewed, significant findings, why those findings matter, limitations, and recommended next steps.
Potentially, but a dispute may require a more formal evidential report. If the purpose is already to support a complaint or dispute, see our Independent Heat Pump Report for Installer Disputes.
An independent assessment can help identify design, documentation and performance concerns in an existing system. The scope should be agreed around what information and access are available before purchase.
Concerned Your Heat Pump System Was Not Designed or Set Up Properly?
If your heat pump is already installed but something does not add up — the house is cold, certain rooms struggle, electricity use is unexpectedly high, the system cycles excessively or the installation simply does not appear to match the original design — you do not have to rely on guesswork.
An Independent Heat Pump Performance Review looks beyond the outdoor unit and considers the heating system as a whole. Depending on the problem and the evidence available, we can review the original heat-loss calculation, heat-pump sizing and manufacturer performance data, radiator and underfloor-heating design, design and actual flow temperatures, pipework, water flow and hydraulic arrangement, weather compensation and controls, domestic hot water and direct-electric backup, commissioning information, and actual comfort and performance evidence.
The objective is not simply to produce a list of possible faults. It is to establish what the system was supposed to do, what it is actually doing, where the two differ and what should be investigated or corrected next.
You receive an independent technical assessment rather than another sales quotation for replacement equipment. If the system is performing badly and you want to understand why before spending more money on remedial work, this is the place to start.
GET AN INDEPENDENT REVIEW
Understand why before spending more money on remedial work.