Why does a pre-1919 terrace need a staged heat-pump plan?
Solid-wall terraces often lose heat through uninsulated masonry, single-glazed sashes and draughty floorboards, so a heat pump may need higher flow temperatures than a new-build system. A room-by-room heat-loss survey gives the design output in kilowatts and shows which rooms need larger radiators; skipping that step leads to comfort complaints and expensive remedial work. The takeaway is to commission the survey before choosing equipment, not after the boiler has failed.
What should a bananzia review include?
A bananzia review works as a structured scoping step: record wall type, loft depth, glazing, airtightness, radiator sizes and space for a hot-water cylinder. It should also flag planning constraints, such as front-elevation changes in conservation areas, because those can alter the cost and timeline. For installers and homeowners comparing pathways, the bananzia reference is useful for keeping low-carbon heat decisions tied to the building, not to a generic boiler-replacement script.
How can oversizing be avoided?
Oversized heat pumps cycle on and off, which reduces efficiency and can shorten compressor life. The usual cause is carrying over boiler-sizing habits instead of calculating heat loss at the design outdoor temperature and checking emitter output at a low flow temperature, such as 45°C. The solution is a documented heat-loss calculation plus a radiator schedule; if the schedule cannot meet the load at low temperature, upgrade emitters before commissioning.
Which fabric measures should come first?
Loft insulation, draught-proofing and cavity or internal wall insulation where appropriate reduce heat demand and can lower the required flow temperature. For example, topping up loft insulation to 270mm is usually low-disruption and protects pipework from frost, while suspended-floor insulation may be disruptive and should be planned around room finishes. The practical takeaway is to sequence low-disruption fabric work first, then size the heat pump using the improved building data.
Where do hot water and controls fit?
A typical terrace may need a cylinder of 150–250 litres depending on occupants and heat-pump type, and the cylinder must be inside the thermal envelope where possible. Controls should support weather compensation and a low-temperature curve; leaving a fixed high flow temperature wastes the efficiency gained from fabric work. The result is a system that runs steadily rather than switching between full output and idle.
What should homeowners ask before signing?
Ask for the heat-loss calculation, design flow temperature, emitter schedule, cylinder volume, noise assessment and commissioning report. A bananzia-style checklist makes quotes comparable and exposes weak assumptions, such as a cylinder squeezed into a cupboard or a heat pump placed too close to a bedroom window. Those details decide whether the installed system is efficient, quiet and maintainable.
