Heat Pumps for Low Carbon Homes

Creating a low carbon home means considering how the building retains heat, how that heat is delivered and how its systems will perform in everyday use. For architects and specifiers, heat pumps offer an opportunity to bring these decisions together from the outset.

Heat pumps can provide efficient heating and hot water while reducing reliance on fossil fuels. Their success depends on the relationship between the building fabric, equipment selection, heat emitters and controls. Specifying them early gives the project team more scope to coordinate performance, comfort and architectural intent. Energy Saving Trust

Start with the building’s heat demand

The starting point for heat pump specification is a clear understanding of the building’s heat loss.

Insulation, glazing, thermal bridging, airtightness and ventilation all influence the heating requirement. For a new home, these should be assessed against the proposed construction. For a renovation, calculations should reflect the improvements that will actually be delivered.

A room-by-room heat loss calculation establishes the output needed to maintain the intended internal temperatures at the local design outdoor temperature. It also informs emitter selection, helping each room achieve comfort at the chosen heating flow temperature. Energy Saving Trust toolkits

For architects, accurate plans and fabric information are valuable inputs to the heating design. If glazing areas, insulation specifications or ventilation arrangements change, the heating designer should review the implications before equipment is ordered.

Design for low temperature heating

Heat pumps generally operate more efficiently when the temperature difference between the heat source and the heating system is smaller. Designing for a lower heating flow temperature can therefore improve seasonal performance.

Underfloor heating is often well suited to this approach, but appropriately sized radiators can also deliver effective low temperature heating. Energy Saving Trust toolkits

Coordinate emitter design with the interiors. Underfloor heating affects floor build-ups and finishes, while radiators require suitable wall space. Resolving these details early helps avoid compromises once layouts are fixed.

The objective is to deliver the required heat to every room at the lowest practical design flow temperature. A heat pump’s ability to produce hotter water should be treated as a capability, rather than a reason to overlook opportunities for efficient system design.

Choose the heat source to suit the site

Air source and ground source systems both have a place in low carbon housing. The appropriate choice depends on the site, available space, ground conditions, budget and project programme.

Air source heat pumps extract heat from outdoor air. Their external positioning should be coordinated with elevations, landscaping, neighbouring properties and the manufacturer’s requirements for airflow and access.

Ground source systems introduce different requirements, including ground array design, excavation or drilling access and internal plant accommodation. Assessing these options early gives the team time to establish what is practical before the site layout and construction sequence are settled. greenheattoolkit.energysavingtrust.org.uk

KronoHP’s domestic range includes the ADAPT 2 air source heat pump and ETERA ground source heat pump, providing options to explore against the project brief.

Match capacity to the design conditions

A model’s nominal capacity does not tell the whole story. The heating designer should check its available output at the project’s design outdoor temperature and required flow temperature.

Oversizing can also create problems. A unit that repeatedly switches on and off to meet a small load can lose efficiency. For homes with a low heating demand, performance during milder weather deserves attention alongside peak winter output. Energy Saving Trust toolkits

Request the relevant manufacturer performance data and agree the selection with the heating designer. This helps establish a specification based on the building’s actual requirements.

Reserve space for hot water and system components

As space heating demand falls in a well insulated home, domestic hot water becomes a more significant part of the overall heating requirement.

The design should account for anticipated occupancy, bathing habits, cylinder capacity and recovery time. A low space heating load does not automatically mean that a small system will meet the household’s hot water needs.

Reserve suitable space for the cylinder and associated equipment, with coordinated pipe routes and access for maintenance. Include the hot water operating strategy in the performance assessment, as its efficiency will differ from low temperature space heating.

Making these provisions part of the architectural layout helps protect usable space and avoids late changes to cupboards or utility rooms.

Integrate the outdoor unit into the architecture

An air source heat pump is part of the external composition of the home. Its appearance and position deserve consideration alongside materials, garden design and views.

The ADAPT 2 range offers a minimalist casing and a choice of finishes, giving designers scope to relate the unit to the building’s palette. Those aesthetic decisions should sit alongside airflow, access and the manufacturer’s installation requirements.

Acoustics also need a site-specific assessment. Sound pressure depends on distance and surroundings, including reflecting surfaces. A published noise figure should therefore be read with its stated measurement conditions and used within an assessment of the proposed location. mcscertified.com

Identify nearby sensitive spaces and neighbouring windows early, and coordinate the unit’s position with the acoustic assessment. This is particularly useful on compact plots where several design priorities compete for the same space.

Compare efficiency figures on a consistent basis

Seasonal Coefficient of Performance, or SCOP, is useful when comparing heat pumps, provided the figures relate to equivalent test conditions.

Check the exact model, climate category and water temperature. A headline value measured for low temperature heating should not be assumed to apply to a system designed for a higher temperature.

Kronoterm publishes a SCOP of up to 6.22 for ADAPT 2. For specification purposes, use the data applicable to the selected model and proposed operating conditions, alongside a project-specific performance estimate.

Keep expected energy use, carbon emissions and running costs distinct. They are related, but running costs also depend on electricity tariffs and how the home is used.

Specify controls and handover as part of the system

Weather compensation adjusts heating flow temperature in response to outdoor conditions, helping the heat pump match the building’s changing demand.

The control strategy should be coordinated with the emitters and intended room temperatures. Commissioning and clear homeowner guidance then help translate that design into comfortable day-to-day operation.

Include commissioning records, operating instructions and maintenance information in the project deliverables. A well specified low carbon home should be straightforward for its occupants to live in.

Discuss your low carbon housing project with KronoHP

Whether you are designing a new home or planning a substantial renovation, early discussion can help establish the heat pump options worth exploring.

KronoHP is the UK distributor of Kronoterm heat pumps. Share your project brief, plans and available heat loss information with our team to discuss the range and the technical information needed to progress your specification.