Independent comparison guide
Quick answer
A ZEB heat battery and an air-source heat pump solve different problems. The right route depends on your heat loss, internal and outdoor space, radiator design, hot-water needs, electricity tariff, installation constraints and priorities. Neither should be chosen from a generic headline saving.
A heat battery stores heat inside the home and releases it to the heating and hot-water system. The practical questions are internal siting, electrical supply, charge windows, thermal storage and survey design.
A heat pump moves heat from outside air into the home. The practical questions are heat loss, outdoor siting, noise, flow temperature, heat delivery and seasonal performance.
The questions that matter
This table explains where the systems differ without presenting volatile prices, grants or product claims as fixed. Each row cites its managed source when it is available; check the linked source before relying on a technical or financial statement.
| Question | ZEB heat battery | Air-source heat pump | What a survey should confirm |
|---|---|---|---|
| How it works · fact: comparison.zeb.heat-outputEvidence record: comparison.zeb.heat-output | Stores heat inside the property, then supplies the heating and hot-water system according to its design and controls. | Moves heat from outside air into the heating and hot-water system using electricity and a refrigeration cycle. | Equipment configuration, controls, heat delivery and property constraints. |
| Purchase and installation cost · fact: grant.bus.current-eligibilityEvidence record: grant.bus.current-eligibility | Needs an itemised survey and quotation covering equipment, electrical work, hydraulics, controls, hot water and enabling works. | Needs an itemised survey and quotation covering outdoor unit, distribution upgrades, hydraulics, controls, hot water and enabling works. | Inclusions, exclusions, warranties, electrical changes, ground works and disruption. |
| Running costs · fact: methodology.heat-pump-spf-designEvidence record: methodology.heat-pump-spf-design | Depends on useful heat, storage losses, efficiency, tariff windows, charging pattern, peak top-ups and any solar contribution. | Depends on useful heat, seasonal performance factor, flow temperature, controls, tariff and any solar contribution. | Whole-year assumptions, rather than a single advertised rate or lab efficiency. |
| Outdoor and internal space · fact: product.zeb.dimensionsEvidence record: product.zeb.dimensions | Explores internal siting, access, weight, ventilation and usable service space. | Explores outdoor siting, clearances, planning and neighbour considerations plus indoor hydraulic space. | Safe location, access, equipment dimensions and future maintenance access. |
| Radiators and flow temperatures · fact: comparison.zeb.temperature-rangeEvidence record: comparison.zeb.temperature-range | Existing wet heating and radiator performance still need careful review; no generic compatibility promise is appropriate. | Heat loss and flow-temperature design are central; radiator and pipework changes may be part of the project. | Room-by-room heat loss, emitter output, pipework, hydraulics and controls. |
| Tariffs and solar · fact: methodology.zeb.usable-storage-limitEvidence record: methodology.zeb.usable-storage-limit | Tariff timing can be particularly relevant because storage can shift some charging; the actual charge mix must be realistic. | Smart controls and solar can help, but seasonal heat demand often does not coincide with solar generation. | Actual tariff windows, metering, solar generation profile and export/import arrangements. |
| Noise, maintenance and lifespan · fact: comparison.zeb.guaranteeEvidence record: comparison.zeb.guarantee | Confirm equipment-specific published requirements and warranty terms from source-linked records. | Outdoor-unit sound, siting and manufacturer-specific maintenance or warranty terms require verification. | Product documents, warranty scope, maintenance plan and neighbour impact. |
| Best and poor fitEvidence record: comparison.zeb.usable-storage | May warrant first investigation where internal storage, tariff flexibility and the existing wet system are key questions. | May warrant first investigation where outdoor siting, heat-loss reduction and low-temperature design are practical. | No fit claim should replace an in-home technical survey. |
Verified-facts assistant
Answers are limited to current, active fact records that have a named source and check date. It will say when no verified answer is available.
Separate equipment price, enabling works, quotation scope and officially verified support. A manufacturer promotion is not automatically a Government grant.
Compare annual useful heat, seasonal performance, tariff windows, standing charges and any solar contribution. Do not assume a ZEB buys all electricity at the cheapest rate.
Compare equipment location, outdoor space, radiator and pipework conditions, cylinder approach, noise considerations, heat loss and the disruption of the proposed design.