Ground Source Heat Lessons for New Build

Why ground source was selected 

Design work for both schemes began when the sector expected earlier restrictions on gas use in new build. Amplius had internal experience with heat pump retrofit and wanted to test ground source while there was still design flexibility. 

The cost uplift was notable. Deep borehole drilling created higher installation costs than air source, with no additional funding available. Amplius viewed the schemes as an opportunity to gather reliable evidence on whole life costs, resident affordability and operational performance. 

The impact of late decision making 

The main challenge was timing. Ground source was selected after key design decisions had already been made. As a result, plant had to be fitted into areas not designed to accommodate it. Storage was lost and larger radiators were required to meet heat loss calculations at lower flow temperatures. 

Externally, the Boston site required temporary access routes for drilling rigs and specific management of drilling material. Coordination between the principal contractor and the specialist installer needed closer oversight than on a standard system. These issues were procedural rather than technical.  

Heating systems only support healthy homes when design decisions, installation planning and resident understanding are aligned.  

Resident experience 

Once operating, ground source systems are stable and quiet. The absence of an external unit reduces exposure to weathering and vandalism. However, internal layout changes affected day to day use. Losing under stairs or cupboard space was a significant adjustment for some households. 

Usability depended on the quality of handover. Clear explanations led to predictable performance and lower running costs. Limited guidance resulted in residents overriding settings or creating usage patterns that reduced efficiency. 

From a Healthy Homes Hub perspective, this is a core issue. Heating systems directly influence indoor environmental quality, including temperature stability, moisture and damp risk. Resident understanding is essential to achieving the intended health outcomes.  

What Amplius will do differently 

Amplius has already applied learning from the schemes. Heating strategy will now be fixed at the earliest possible stage. Heat pump specialists will be involved from the start of design rather than after planning. Internal plant space will be planned intentionally, and contractor responsibilities will be defined more clearly. 

The organisation does not view ground source as the universal solution. Suitability depends on site conditions, cost and layout. The key lesson is that the success of any low carbon system is shaped by design sequencing, early coordination and resident preparation.  

Next steps for housing providers 

• Apply the heat strategy at the start of scheme design. 

• Integrate specialist suppliers in early design stages. 

• Allocate internal plant space deliberately rather than reactively. 

• Define responsibilities clearly across all contractors and trades. 

• Provide practical, simple resident guidance to support correct system use.