Air-source heat pumps
Extract heat from the outdoor air and transfer it into a water-based central-heating system.
- Often the most straightforward heat-pump option
- Requires suitable outdoor-unit positioning
- May involve radiator or pipework changes
Ground-source heat pumps
Use pipework buried in the ground or installed in boreholes to collect low-level heat.
- Requires suitable land or drilling access
- Installation work is usually more extensive
- Can provide stable year-round heat collection
Air-to-air heat pumps
Transfer heat from outdoor air to indoor fan units rather than water-filled radiators.
- Provides warm air directly into rooms
- Does not normally provide domestic hot water
- Indoor-unit positioning is important
Biomass boilers
Burn suitable biomass fuel to heat water for radiators and domestic hot-water systems.
- Requires fuel storage and delivery access
- Needs regular servicing and ash management
- Often considered for selected rural properties
Quick comparison
How the systems differ
| System | Heat delivery | Space needed | Hot water | Often considered for |
|---|---|---|---|---|
| Air-source heat pump | Water-based radiators or underfloor heating | Outdoor unit and suitable internal equipment space | Usually with a compatible hot-water cylinder | Many houses and suitable flats or small buildings |
| Ground-source heat pump | Water-based radiators or underfloor heating | Ground loops, trenches or boreholes plus internal equipment | Usually with a compatible hot-water cylinder | Properties with land, drilling access or shared-loop potential |
| Air-to-air heat pump | Warm air through indoor fan units | Outdoor unit and one or more indoor units | Normally requires a separate hot-water solution | Selected homes needing space heating or room-by-room control |
| Biomass boiler | Water-based radiators or underfloor heating | Boiler, fuel storage and delivery access | Can provide domestic hot water | Selected rural or off-grid properties |
A comparison table cannot replace a system design.
The installer should calculate the building’s heat loss and explain the proposed output, controls, emitters, hot-water arrangement and expected installation work.
Property factors
What should be assessed?
Heat loss
Room-by-room heat-loss calculations help determine the output needed to keep the property comfortable.
Insulation
Loft, wall, floor, window and draught performance can affect heating demand and system sizing.
Radiators
Existing radiators may need checking or replacing to deliver enough heat at the proposed flow temperature.
Hot water
The assessment should consider household demand, cylinder size, recovery time and available cupboard space.
Outdoor space
Unit location, airflow, access, boundaries and potential noise impact should be reviewed carefully.
Electrical supply
The installer may need to check the consumer unit, available capacity and any required electrical work.
Choosing well
A practical way to compare your options
Describe the property
Share the building type, size, postcode, current heating and any recent insulation work.
Arrange an assessment
Ask for a proper heat-loss assessment and explanation of the proposed system design.
Compare quotations
Check what is included, expected disruption, controls, warranties and the total amount payable.
Review the evidence
Make sure the recommendation is based on the property rather than a generic product estimate.