This online resource is a practical guide for site managers, designed to highlight common issues and best practice in heat pump installation. It includes links to external guidance and provides support for each stage of the heat pump installation process, from groundworks to commissioning. This content does not replace the need for a qualified technical team or detailed design and installation guidance from manufacturers and specialist trades.
This online resource is a practical guide for site managers, designed to highlight common issues and best practice in heat pump installation. It includes links to external guidance and provides support for each stage of the heat pump installation process, from groundworks to commissioning. This content does not replace the need for a qualified technical team or detailed design and installation guidance from manufacturers and specialist trades.
Colour tags denote a checklist item is only relevant to the noted technology.
ASHP = Air source heat pump
HP = Heat pump
🟣 AWHP = Air to water heat pump (hot water heat pump)
🟠 GSHP = Ground source heat pump
🔵 UFH = Underfloor heating
🟡 R290 = Refrigerant grade propane
Colour tags denote a checklist item is only relevant to the noted technology.
HP: Heat pump
ASHP: Air source heat pump
🟠 GSHP: Ground source heat pump
🔵 UFH: Underfloor heating
🟡 R290: Refrigerant grade propane
🟣 AWHP: Air to water heat pump
DOCUMENTATION
See further heat pump guidance available on the Knowledge Centre
See further heat pump guidance available on the Knowledge Centre
See further heat pump guidance available on the Knowledge Centre
DOCUMENTATION
See further heat pump guidance available on the Knowledge Centre
See further heat pump guidance available on the Knowledge Centre
See further heat pump guidance available on the Knowledge Centre
GROUNDWORKS
Different installation methods can be used for wet underfloor heating, and an appropriate method should be chosen to suit the floor build up.
UFH on ground floor concrete slabs commonly use pipework clipped on top of insulation and cast within a thin screed.
With this buildup, even pipework spacing to the heating designer's specification, regular screed depth and appropriate floor coverings are key to ensuring good performance.
Ground source heat pumps require a ground collector pipework loop to transfer energy from / to the ground. Typically, either slinky coils or borehole loops are installed.
As significant excavation is required for both of these approaches, laying of these pipes should be carefully programmed so that the loop is laid in time for commissioning while avoiding damage by plant operations or other groundworks in the area.
GROUNDWORKS
Different installation methods can be used for wet underfloor heating, and an appropraite method should be chosen to suit the floor build up.
U'FH on ground floor concrete slabs commonly use pipework clipped on top of insulation and cast within a thin screed.
With this buildup, even pipework spacing, regular screed depth and appropriate floor coverings are key to ensuring good performance.
Different installation methods can be used for wet underfloor heating, and an appropriate method should be chosen to suit the floor build up.
UFH on ground floor concrete slabs commonly use pipework clipped on top of insulation and cast within a thin screed.
With this buildup, even pipework spacing to the heating designer's specification, regular screed depth and appropriate floor coverings are key to ensuring good performance.
Ground source heat pumps require a ground collector pipework loop to transfer energy from / to the ground. Typically, either slinky coils or borehole loops are installed.
As significant excavation is required for both of these approaches, laying of these pipes should be carefully programmed so that the loop is laid in time for commissioning while avoiding damage by plant operations or other groundworks in the area.
FIRST FIX
Heating engineers should be fully trained and competent on the installation tasks that they are carrying out or closely supervised if not. The heating installer should make sure a senior engineer is coordinating work on site and monitoring junior engineers closely.
Heat pump systems are sensitive to incorrect flow rates so it is important to make sure that the pipework installed matches the specification, noting that different specifications may be required for different branches of pipework.
Make sure that as well as checking the install quality and insulation, the inner diameter and wall thickness of plastic pipework is checked, not simply the outer diameter.
Primary pipework runs between the outdoor ASHP unit and the distribution point, usually near the hot water cylinder in the service cupboard. This pipe run should be fully insulated and typically run in a larger diameter than other heating distribution pipes. While the agreed design should be consulted for specifics, a run length of <10m is generally considered good practice.
It's important to make sure that exposed equipment is protected from damage and dust prior to handover. Outdoor heat pump units are naturally exposed and cages / protective covers should be considered to protect from knocks. Internally, components like UFH manifolds should be protected before being boxed in. Consider locking the service cupboard to prevent accidental damage during fitout.
As pipework diameters may be larger than for gas boiler systems, the specification and location of radiator outlet plates important to get right, allowing for sweeping bends and ease of connections.
Check with the design to make sure the correct trunking specification and routing has been installed where this is required. Any deviations should have been agreed with the responsible heating designer and recorded.
Make sure that the critcial path to commissioning is planned and all related trades are programmed to complete their works in the right sequence in advance.
FIRST FIX
Heating engineers should be fully trained and competent on the installation tasks that they are carrying out or closely supervised if not. The heating installer should make sure a senior engineer is coordinating work on site and monitoring junior engineers closely.
Heat pump systems are sensitive to incorrect flow rates so it is important to make sure that the pipework installed matches the specification, noting that different specifications may be required for different branches of pipework.
Make sure that as well as checking the install quality and insulation, the inner diameter and wall thickness of plastic pipework is checked, not simply the outer diameter.
Primary pipework runs between the outdoor ASHP unit and the distribution point, usually near the hot water cylinder in the service cupboard. This pipe run should be fully insulated and typically run in a larger diameter than other heating distribution pipes. While the agreed design should be consulted for specifics, a run length of <10m is generally considered good practice.
It's important to make sure that exposed equipment is protected from damage and dust prior to handover. Outdoor heat pump units are naturally exposed and cages / protective covers should be considered to protect from knocks. Internally, components like UFH manifolds should be protected before being boxed in. Consider locking the service cupboard to prevent accidental damage during fitout.
As pipework diameters may be larger than for gas boiler systems, the specification and location of radiator outlet plates important to get right, allowing for sweeping bends and ease of connections.
Check with the design to make sure the correct trunking specification and routing has been installed where this is required. Any deviations should have been agreed with the responsible heating designer and recorded.
Make sure that the critcial path to commissioning is planned and all related trades are programmed to complete their works in the right sequence in advance.
SECOND FIX
For a heat pump system to work efficiently, perform as required, and for the energy assessment to be compliant it is critical that the system is installed according to the design. Check that all major components, pipework, insulation controls and ancillaries are installed as specified.
Any proposed design changes need to be checked and agreed by the responsible heating designer to make sure system performance and energy assessment compliance will not be affected. Where agreed, changes must be recorded and design / construction information updated so that there is no ambiguity or coordination issues on site.
While pipe sizes may seem trivial, unlike boiler systems heat pump systems are finely balanced and much more efficient. This means that changes to the designed flow rates and heat losses that can be caused by incorrect pipe sizing can lead to issues in commissioning and operation, and may be non-compliant.
SECOND FIX
For a heat pump system to work efficiently, perform as required, and for the energy assessment to be compliant it is critical that the system is installed according to the design. Check that all major components, pipework, insulation controls and ancillaries are installed as specified.
Any proposed design changes need to be checked and agreed by the responsible heating designer to make sure system performance and energy assessment compliance will not be affected. Where agreed, changes must be recorded and design / construction information updated so that there is no ambiguity or coordination issues on site.
While pipe sizes may seem trivial, unlike boiler systems heat pump systems are finely balanced and much more efficient. This means that changes to the designed flow rates and heat losses that can be caused by incorrect pipe sizing can lead to issues in commissioning and operation, and may be non-compliant.
COMMISSIONING
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
Even with a competent and experienced commissioning engineer in place it is important to have a member of the site team to oversee a proportion of the plots as they are commissioned.
Some homebuilders find that the only way to ensure that no homes have issues with their heating is to witness the commissioning of every heatpump.
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
Note where installing to MCS requirements the installation company’s Technical Supervisor must also sign the commissioning sheets.
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
COMMISSIONING
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
Even with a competent and experienced commissioning engineer in place it is important to have a member of the site team to oversee a proportion of the plots as they are commissioned.
Some homebuilders find that the only way to ensure that no homes have issues with their heating is to witness the commissioning of every heatpump.
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
Note where installing to MCS requirements the installation company’s Technical Supervisor must also sign the commissioning sheets.
See Heat pump commissioning - Hints & tips for more information
See Heat pump commissioning - Hints & tips for more information
FUTURE HOMES HUB
Householder guidance: Buying a new low energy home - heat pump edition
The Hub’s Householder Guidance for heat pumps provides a good starting point describing the components of a low energy home, including heat pumps. While this targets the homeowner/buyer, designers may find this helpful as an introduction.
MICROGENERATION CERTIFICATION SCHEME
Heat Pump: Design Standard
MCS MIS-3005 is a technical design standard, elements of which are often referenced as design criteria and by third party guidance.
CHARTERED INSTITUTION OF BUILDING SERVICES ENGINEERS
Domestic Heating Design Guide
The CIBSE Domestic Heating Design Guide is a commonly referenced detailed technical
guidance document intended predominantly for MEP/heating engineers. Architects may find this helpful to better understand technical fundamentals.
PASSIVHAUS TRUST
Air to water heat pumps: The basics of energy efficiency
This short Passivhaus Trust guidance document focusses on the principles of low energy design that should be applied early in the design process.
HEAT PUMP ASSOCIATION UK (HPA UK)
Online technical resources
The HPA UK publishes numerous practical technical resources including guidance documents and webinars. Notable publications accessible here include their “Heat Pump Commissioning Checklist & Service Record” template and “Field Assessment of Air Source Heat Pump Noise” guidance.
ENERGY SAVING TRUST
Heat pumps: how they work, costs and savings
This online resource provides a basic overview of heat pump technology which may be useful for designers looks to familiarise with the technical fundamentals including benchmark performance and costs.
