What Bananzia Means in a Heat Retrofit
Bananzia is a working label for a neighbourhood-scale, fabric-first audit that tests whether a home can run a heat pump at low flow temperature. The unit of analysis is the building envelope, emitter area and hot-water demand, not the boiler being replaced. A solid-wall terrace with 6 kW peak heat loss and radiators sized for 70°C flow presents a different problem from a 1970s estate with cavity insulation and underfloor loops. The audit records those differences before any equipment is specified.
Context matters because heat pumps lose efficiency as flow temperature rises. Development work therefore starts with a room-by-room heat-loss calculation, not a catalogue quote. The result is a ranked list of interventions: loft insulation first, then draught-proofing, then radiator upgrades or larger emitter surfaces. That sequence keeps capital cost down and avoids oversizing the compressor.
Step 1: Measure Fabric Before Heat Source
The first pass in bananzia is a measured survey of walls, roofs, floors and glazing. A common finding is that a home quoted for a 12 kW heat pump needs 7 kW after basic fabric work. The takeaway is blunt: fabric measures change the equipment size, so they belong in the same plan as the heat pump.
- Record U-values or construction type for each thermal element.
- Test air permeability with a blower door where available.
- Flag cold bridges at bay windows, party walls and loft eaves.
Step 2: Map Emitter Capacity and Flow Temperature
Emitter mapping is where many retrofits fail. A room with a 600 mm radiator may need a 1200 mm replacement to deliver the same heat at 45°C flow instead of 70°C. Bananzia treats radiator sizing as a design task, not a plumbing afterthought. The result is a room schedule that pairs heat-loss figures with emitter output at the target flow temperature.
For example, a 4 m by 5 m living room with 1.8 kW design heat loss and a target flow of 45°C may need 2.4 m of Type 22 radiator or equivalent underfloor area. The takeaway: check emitter capacity before choosing a heat pump model.
Step 3: Sequence Shared Infrastructure
Street-level coordination is the practical advantage of bananzia. If three adjacent homes each plan a separate outdoor unit and hot-water cylinder, the shared cost of trenching, grid upgrades and scaffolding can be reduced. A terrace can agree a common plant area, a single thermal store or a shared ground array where space allows.
The development result is a phased plan: fabric measures in year one, emitter upgrades in year two, and heat-pump installation when the measured heat loss supports a low flow temperature. That order protects householders from buying equipment that has to be replaced once insulation arrives.
What the Result Looks Like
A completed bananzia audit produces a one-page home heat plan: current heat loss, target flow temperature, emitter changes, fabric measures and a realistic installation window. It is not a sales document. It is a technical brief that an installer, retrofit coordinator and householder can all use. The strongest result is a smaller heat pump, a lower flow temperature and fewer surprises on commissioning day.