System: 13 x MasterTherm AQ17i Ground Source Heat Pumps
Sector: Residential - social housing
Location: Cardiff
Date: November 2023
Boreholes: 5 x 150m deep
Overview:
The Cardiff Living Project was developed to address two key challenges:
- The urgent need for affordable, energy-efficient housing for social rent in Cardiff.
- The requirement to meet ambitious sustainability targets while ensuring long-term reliability and resident comfort.
Designing a renewable energy system for multiple homes within a compact development required careful planning. The solution needed to minimise disruption, maximise efficiency, and deliver consistent heating and hot water across all 13 properties — all while keeping running costs affordable for residents.
Challenge:
The project aimed to set new standards for sustainable, assisted community living by creating a fully renewable heating and hot water system for all 44 apartments.
The challenge lay in developing an integrated solution that could:
- Provide consistent high-temperature hot water suitable for multiple dwellings.
- Operate efficiently year-round while meeting stringent sustainability targets.
- Support residents’ comfort and independence through intelligent, easy-to-use controls.
- Align with the long-term environmental objectives of Cardiff Council and the Welsh Government.
Solution:
Thermal Earth delivered a fully renewable heating and hot water solution centred on a shared ground loop array linked to 13 individual MasterTherm AQ17i ground source heat pumps.
System design:
• A shared network of five boreholes, each drilled to depths of up to 150 metres, provides access to stable ground temperatures for efficient heat exchange.
• Each property is fitted with a MasterTherm AQ17i GSHP (range 3–15 kW), offering individual heating and hot water control.
• Smart PGDX controllers enable precise energy management, monitoring performance in real time and optimising consumption.
• Integration with Agile Octopus smart tariffs allows residents to take advantage of dynamic electricity pricing, reducing operational costs and encouraging energy-conscious behaviour.
The result is a resilient, low-carbon heating network that ensures every home enjoys high performance, flexibility, and sustainability — without reliance on fossil fuels.
Key Benefits:
|
Renewable heating network |
Shared ground loop array harnesses stable underground temperatures for efficient, low-carbon heating. |
|
Individual system control |
Each property benefits from its own MasterTherm AQ17i unit for personalised comfort. |
|
High efficiency |
Inverter-driven compressors and PGDX controllers optimise performance and energy use. |
|
Smart energy management |
Integration with Agile Octopus tariffs enables dynamic cost control and lower energy bills. |
|
Sustainable design |
Significantly reduces carbon emissions and supports Cardiff’s net-zero objectives. |
|
Resident empowerment |
Smartphone app allows residents to monitor and adjust heating conveniently. |
Results:
• 13 energy-efficient homes providing reliable, renewable heating and hot water
• Substantial reduction in carbon emissions compared to fossil fuel systems
• Optimised energy use and lower operational costs for residents
• Contribution to Cardiff Council’s social housing and net-zero goals
• Model example of collaborative, sustainable community development
