What to consider when installing a heat pump in an older building
Sachin Vibhute, HVAC and Heat Pumps Technical Consultant at LG
The age of a building tells you surprisingly little about whether a heat pump will be easily installed or not. However retrofitting heat pumps is generally assumed to be a more difficult task, especially with the majority of heating systems in the UK being designed long before heat pumps were even created.
Look beyond the assumptions
Before installation, an engineer will want to establish how the current system operates, and how much heat is retained or released. The existing pipework and insulation will affect what is possible, and some buildings will need alterations before a heat pump can work effectively.
Underfloor heating is frequently regarded as a prerequisite for heat pumps, but this isn’t always accurate; while it works very well with them, it is not essential. What matters is whether the heating system can deliver the heat the building needs at the temperatures the heat pump is designed to provide.
Cold weather is frequently cited as another reason heat pumps are ruled out too quickly. On the contrary, the temperatures experienced in a UK winter are well within the territory heat-pump engineers are already exploring. At LG, we’ve established a research consortium in Alaska in 2023 to study high-efficiency cold-climate heat pumps, with research partners testing performance in labs there.
Naturally, some buildings will prove more difficult once the assessment begins. Space may be tight or the building may have a larger heat demand. In those cases, several heat pumps can be configured in a cascade arrangement, sharing the load between them. Individual units can then come into operation as the building needs them, allowing the system to respond to changes in demand. This can be particularly useful where the available plant space makes a single larger unit difficult to accommodate. It also gives engineers more scope to work with the constraints of an existing building, finding a configuration that fits the space and heat demand they have.
The assessment also extends beyond the heating system itself. An installer will need to consider where the equipment can be located and whether the Distribution Network Operator needs to be notified before or after installation.
The installation itself needs planning around how the building is used. The time required will depend on its scale and complexity, and connecting a new system can mean some disruption to heating and hot water. Fortunately, forward planning can help keep that disruption to a minimum.
Working with the existing building stock
Gas heating is still the primary source of emissions from public-sector buildings in the UK. Many of these premises will remain in use for years to come and require installation of new energy systems as the drive for clean energy accelerates.
Heat pumps can provide around three to four units of heat for every unit of electricity they consume because they draw heat from their surroundings and transfer it into the building. The IEA estimates that they can reduce greenhouse-gas emissions by at least 20%, compared with gas boilers, even when the electricity supplying them is emissions intensive. As more renewable electricity comes onto the grid, the emissions associated with running them can fall further.
Across an estate, an assessment can help to identify the buildings where heat-pump deployment can begin and those that will need more work. Some might require changes to the fabric or existing heating system before installation makes sense. That gives energy managers a practical basis for deciding where to start and what work will be needed before the unit is mounted.
The importance of practical training
To scale heat-pump installations, and reduce energy emissions, it’s crucial to address the current skills gap. Heat-pump training must put installers in front of the equipment itself, from system design through to commissioning and troubleshooting. Practical training in facilities that recreate real installation conditions helps build problem solving skills before having to deal with them on site. Installers also need the confidence and experience to install heat pumps in a number of different applications including historic properties through to contemporary offices.
A detailed up front assessment can help establish any complexities indicating what is and isn’t possible, across a large estate, that gives energy managers the chance to plan for difficult buildings, broadening the reach of the decarbonisation programme.
This article appeared in the September 2026 issue of Energy Manager magazine. Subscribe here.
