Overview
Carbon3 was appointed to deliver a full Air Source Heat Pump (ASHP) replacement programme across 124 homes at an estate in Bulford. The existing systems, installed during construction, were found to be under-specified and inconsistently delivered, resulting in poor performance, higher running costs for residents and frequent operational issues. Carbon3 carried out a full technical review before developing a comprehensive upgrade solution that addressed both the heating equipment and the underlying system design.
Project Background
During early surveys and intrusive inspections, it became clear that the original ASHP and underfloor heating (UFH) installations did not meet required standards. UFH loops were missing in several homes, spacing varied significantly between plots and heat transfer was inconsistent across ground-floor zones. These fundamental issues forced heat pumps to operate at elevated temperatures, increasing energy consumption and reducing system lifespan.
Our investigation confirmed that replacing the existing units on a like-for-like basis would not resolve the deeper engineering and design problems. A full-scale redesign was required to deliver a long-term, efficient and reliable heating solution.
Our Investigation
Carbon3 undertook detailed technical assessments across a representative sample of properties, reviewing heat pump behaviour, internal temperatures, cylinder configuration and UFH performance. This highlighted a pattern of elevated flow temperatures, long run times and poor heat distribution, resulting in cold spots and resident discomfort. Several cylinders were also found to be incorrectly set up, meaning systems were unable to operate within their intended parameters.
These findings formed the foundation for a redesigned heating strategy tailored to each property.
Our Solution
Carbon3 delivered a complete heating system upgrade across the estate, including both mechanical improvements and enhanced digital monitoring.
Heating System Redesign
We completed full heat loss calculations for every property, allowing us to correctly size radiators and design revised heating circuits. In homes where UFH performance could not deliver consistent heat, we transitioned properties to fully balanced radiator systems.
New ASHP and Hot Water Systems
We installed Mitsubishi 8.5 kW air source heat pumps paired with new 250L pre-plumbed cylinders. All systems were configured to operate within optimal temperature ranges, improving energy efficiency and overall performance.
Advanced Controls and Monitoring
Each property was fitted with a remote management platform that allows the client to:
- Diagnose issues remotely
- Monitor system performance in real time
- Control heating and hot water in void properties
- Track running costs and system trends
This digital layer reduces reactive maintenance visits and improves asset visibility across the estate.
Delivery
All works were carried out by Carbon3’s directly employed engineers, supported by our project management team. Close coordination ensured minimal disruption to residents, with clear communication, scheduled appointments and dedicated liaison support throughout. Our team also worked closely with the client to align delivery with operational requirements and estate-wide heating policies.
Outcomes and Results
The programme has delivered significant improvements in performance, efficiency and resident experience. By redesigning the system, rebalancing heating circuits and installing correctly sized equipment, running costs have been reduced by an estimated 20 to 30 percent. Homes now benefit from consistent, reliable heat across all rooms, improved EPC ratings and reduced likelihood of breakdowns.
The client also now has full visibility of system performance across all 124 properties, supporting proactive maintenance, reduced downtime and easier management of void homes.
The 124 upgraded ASHPs are estimated to reduce carbon emissions by around 212 tonnes CO₂ per year, based on typical household heat demand and a seasonal performance factor of 3.0. Actual savings may vary depending on occupancy, heating patterns, and the grid’s carbon intensity.
Summary
This upgrade demonstrates the value of tackling both the technical installation and the underlying heating design. Carbon3’s end-to-end approach has delivered a future-proofed ASHP solution that improves resident comfort, reduces operational costs and strengthens long-term asset performance.
If your social housing heat pumps aren’t functioning as they should, contact us today for a survey.
