Air-to-Water · R290 · Boiler replacement
Daikin Altherma 4 H
Daikin's Altherma 4 H is the R290 air-to-water heat-pump range for residential boiler-replacement projects. It is designed for retrofit homes with existing radiators and can deliver leaving-water temperatures of up to 70–75°C in suitable conditions, with operation down to approximately -28°C outdoors.
R290 is a natural refrigerant with very low global-warming potential. The system provides heating and domestic hot water, and supports integration with existing or upgraded radiators, underfloor heating, and compatible hot-water tanks — all confirmed on survey.
Features
- R290 natural refrigerant with very low global-warming potential.
- High-temperature heating — leaving-water temperatures of up to 70–75°C in suitable conditions.
- Designed for retrofit homes with existing radiators, subject to assessment.
- Heating and domestic hot water in one system.
- Wall-mounted (4 H W) and floor-standing (4 H F) indoor-unit options.
- Optional cooling in suitable configurations.
- Operation in cold outdoor conditions — down to approximately -28°C.
- Smart-home connectivity through compatible Daikin controls.
Why consider Altherma 4 H?
- R290 natural refrigerant with very low global-warming potential.
- Leaving-water temperatures of up to 70–75°C for many radiator retrofit homes.
- Wall-mounted or floor-standing indoor-unit arrangements.
- Integrated 180-litre or 230-litre tank option on Altherma 4 H F.
- Designed for residential boiler-replacement and modernisation.
- Operation down to approximately -28°C outdoors in suitable conditions.
- Optional cooling in suitable configurations.
- Smart-home connectivity through compatible Daikin controls.
Choose your indoor-unit option
Two indoor arrangements — wall-mounted with a separate tank, or floor-standing with an integrated cylinder. Survey confirms which fits the plant space and hot-water demand.
Wall-mounted
Altherma 4 H W
Flexible indoor unit that connects to a separate compatible domestic-hot-water tank. Worth considering where floor space is limited, a separate cylinder is preferred, or an existing tank may be suitable for retention.
Hot water: separate compatible tank — installer confirms whether retention or replacement is right for the home.
Floor-standing · All-in-one
Altherma 4 H F
Compact integrated arrangement: heat-pump controls and hydraulic components with a stainless-steel domestic-hot-water tank in one floor-standing unit. Suited where a new tank is needed and a neat, packaged installation is preferred.
Hot water: integrated tank — 180 litres or 230 litres, depending on the selected configuration.
Suitable for boiler replacement
Altherma 4 H is designed for residential modernisation and retrofit. It can work with traditional radiators, although every room and radiator must be checked at the proposed heat-pump operating temperature. Compatibility cannot be confirmed from the model alone — a room-by-room heat-loss calculation and technical survey are required.
- Replacing the gas boiler.
- Retaining suitable existing radiators, or upgrading selected radiators where required.
- Reusing or replacing some pipework.
- Retaining a compatible hot-water tank, or installing a new 180-litre or 230-litre tank.
- Improving controls and system balancing.
- Connecting solar PV or other compatible energy systems where planned.
Which system may suit you?
An initial guide only. Final specification depends on the property survey, heat loss, hot-water demand, radiator output, pipework, electrical supply and available installation space.
| Your home or project | Option to investigate |
|---|---|
| Existing boiler and radiators | Altherma 4 H W or Altherma 4 H F |
| Limited floor space | Altherma 4 H W |
| New hot-water cylinder required | Altherma 4 H F |
| Existing compatible hot-water tank | Altherma 4 H W |
| Larger household hot-water demand | 230-litre Altherma 4 H F, or a suitably sized separate tank |
| Radiators you hope to retain | Either option, subject to heat-loss and radiator assessment |
| Underfloor heating | Either option, subject to system design |
| Solar PV planned or already installed | Either option, subject to controls and electrical design |
What Pretium Synergy will assess
Before recommending a system, we review whether Altherma 4 H W, Altherma 4 H F, or another R290 configuration is appropriate for your home.
- Property size and construction, and room-by-room heat loss.
- Existing boiler, controls, radiators, pipework and circulation.
- Existing hot-water cylinder and required capacity.
- Outdoor-unit position, noise and clearances.
- Electrical supply.
- Solar PV, battery and EV-charging plans.
- Planning, building-regulation and installation requirements.
Register interest
Considering replacing your boiler with an R290 air-source heat pump? Tell 
Current about your home, current heating system and hot-water needs — we'll discuss Altherma 4 H W or 4 H F options and the next step. No online checkout.
This page focuses on Daikin's Altherma 4 H R290 residential range. Availability, model numbers, tank options, specifications and incentives should be confirmed for each project. A final recommendation needs a qualified site survey, heat-loss calculation, radiator and pipework assessment, hot-water assessment, and confirmation of electrical and installation requirements. R290 systems must be installed in accordance with applicable regulations by appropriately qualified personnel.
