16 June 2026
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Heat pump installations in the UK are increasing, but many systems underperform due to poor setup – not the units themselves. Daniel McCowan, Director at ServiceMy, discusses how better servicing and adjustments can improve performance and reduce costs.
Heat pump installations have increased quickly across the UK over the last few years. With funding support and a wider push towards low carbon heating, more systems are now being installed across homes, housing stock and commercial buildings. While that growth is positive, it is becoming clear that not all systems are performing as expected once they are in use.
From a servicing point of view, there is a noticeable gap between installation and how systems perform over time. Many systems are running, but not efficiently. Some struggle to heat properties properly, others run at higher costs than expected, and some operate continuously without delivering the level of comfort the customer was expecting. In most cases, the heat pump itself is not the problem. It is the wider system around it.
Why heat pumps underperform on site
One of the most common issues found when attending properties is emitter sizing. Radiators are often too small for low flow temperature systems, particularly in retrofit homes where existing emitters have been retained. The system may eventually reach temperature, but it does so slowly and has to work harder to get there. This often leads to higher flow temperatures being used to compensate, which reduces efficiency and increases running costs.
Heat loss assumptions are another factor. If the original calculations do not reflect the actual condition of the property, the system can be undersized from the outset. This becomes more noticeable during colder periods, where the system has little capacity to deal with increased demand.
Flow temperature settings also play a key role. Many systems are left on fixed f low temperatures rather than being set up with weather compensation. This means the system continues to run at the same output regardless of external conditions. During milder weather, this results in unnecessary energy use, while colder conditions can expose the system’s limits.
Controls are another regular issue. It is not unusual to find zoning that does not reflect how the property is used, thermostats positioned in poor locations, or schedules that do not match occupancy patterns. In some cases, controls are present but have not been set up correctly, or the end user has not been shown how to use them. These issues are often overlooked at handover but have a direct impact on both comfort and efficiency. Commissioning can also vary. While systems may be signed off, the level of detail in commissioning is not always consistent. Flow rates may not be fully balanced, and system settings may not be fine-tuned to suit the property. This can leave the system operating below its potential from the start.
There are also cases where several smaller issues combine. Individually they may not cause a major problem, but together they result in a system that does not perform as expected. This is a common scenario where no single fault stands out, but the overall performance is poor.
What this means for the end user
For homeowners, these issues tend to present in similar ways. Rooms not reaching temperature, particularly on upper floors. Systems running for long periods without achieving the desired result. Higher than expected energy bills. Or uncertainty around whether the system is working as it should.
This often leads to frustration, especially where expectations have been set around efficiency and running costs. In many cases, the heat pump itself is blamed, when the issue lies elsewhere within the system.
For landlords, housing providers and facilities management companies, the impact is more operational. Increased call outs, repeat visits and ongoing complaints can put pressure on maintenance teams. Without properly identifying the cause, these issues can continue over long periods and lead to unnecessary costs.
The role of servicing
Servicing is often treated as a routine requirement, focused on checks and basic maintenance. In practice, it should be used to assess how the system is performing and make adjustments where needed.
A well carried out service goes beyond standard checks. It includes reviewing flow temperatures, checking control settings, and assessing how the system is operating over time. This helps build a clearer picture of whether the system is working as intended.
Servicing is also an opportunity to identify smaller issues early. A minor imbalance, incorrect setting or small fault can affect performance if left. Addressing these during a service visit can prevent them from developing into larger problems.
Another important part of servicing is engaging with the end user. Heat pumps operate differently to traditional heating systems, and not all customers are familiar with how they should be used. Simple guidance around controls, scheduling and expectations can often resolve issues that might otherwise result in further call outs.
Servicing also allows for performance checks against the original design. If the system is not operating within a reasonable range, further investigation can be carried out.
A more proactive approach
There is still a tendency within the sector to respond to issues once they have been raised by the customer. By that point, the customer has already had a negative experience.
A more effective approach is to review systems regularly and make adjustments over time. This helps keep systems running efficiently and reduces the likelihood of problems developing.
For larger portfolios, such as housing associations or facilities management contracts, this approach can make a noticeable difference. Fewer reactive call outs, improved system performance and better customer satisfaction all contribute to smoother day to day operations.
It also allows for trends to be identified across multiple properties. If the same issue is being seen repeatedly, it can be addressed at a wider level rather than on a case-by-case basis.
Closing the gap
Improving heat pump performance requires a joined-up approach. Installation, commissioning and servicing all play a part.
Getting the initial design right is important, but it is equally important to review how the system performs once it is in use. Servicing provides that opportunity and helps ensure the system continues to operate as intended.
There is also value in feeding back what is found on site. Common issues identified during servicing can help improve future installations and reduce repeat problems.
Conclusion
Heat pumps can deliver reliable and efficient heating, but only when the full system is set up and maintained properly. The issues being seen across many properties are generally related to system design, commissioning and operation, rather than the heat pump itself. Servicing should be used to maintain and improve performance, not just to carry out basic checks. With installations continuing to increase, making sure systems perform properly in real conditions will be key to maintaining confidence in the technology and supporting wider adoption across the UK.
https://servicemy.co.uk
