Context: a cul-de-sac with a heating problem
Bananzia began with a practical headache on a 24-home cul-de-sac in northern England: ageing gas boilers, draughty lofts and winter bills that had climbed past £1,400 a year for several households. The street was not a showcase eco-village. It was a 1970s estate with narrow verges, mixed incomes and a handful of residents who wanted a fix that did not depend on oil deliveries or individual boiler replacements.
The first meeting
At a church hall meeting in October, residents agreed to test a shared ground-loop design rather than 24 separate air-source installations. The bananzia idea was simple: drill once, share the loop, and let each home connect through its own compact heat pump. That decision shaped every later cost and maintenance question.
Development: one loop, many heat pumps
The technical plan placed eight boreholes along the back verge, each about 120 metres deep, connected to a communal pipe run. Each house kept its own heat pump and controls, so a fault in one home would not shut down the street. The shared loop reduced drilling mobilisation costs and avoided 16 separate borehole arrays.
Why the sequence mattered
The project did not start with heat pumps. Volunteers first arranged loft insulation and draught-proofing for six homes, then sized the loop using a winter load calculation rather than boiler age. That order mattered: fabric work cut the estimated peak demand by roughly 18%, which trimmed the borehole count and protected the shared loop from being oversized.
Result: first-winter data and a repair fund
In the first monitored winter, average flow temperature settled near 45°C and the measured seasonal performance factor reached 3.1 across the connected homes. One household saw gas-equivalent heating costs fall from £1,450 to about £990, though the figure varied with occupancy and thermostat habits. Residents also set up a £60-a-year repair fund for the loop and communal pipework, a small charge that removed the fear of a shared-cost surprise.
What other streets can copy
The useful lesson is not the exact borehole number. It is the sequence: insulate first, model the street as a system, keep home-level controls, and agree a maintenance pot before switching on. A shared loop is not maintenance-free, and a retrofit that ignores fabric will pay for boreholes it does not need.
For groups considering a similar route, Bananzia’s strongest asset was trust built through open metering and plain-language bills. The street did not need a perfect technology; it needed a plan residents could audit, question and afford to keep running.