Daikin Altherma is Daikin's air-to-water heat pump family for wet heating and often hot water. Daikin split air conditioning is air-to-air: indoor fan coils that cool and often heat air. Daikin Altherma air conditioning searches mix two products. Altherma can sometimes provide cooling through underfloor or fan coils if the design allows, but it is not a bedroom wall split. A wall split will not heat radiators. Choose Altherma when you are replacing a boiler. Choose a split when you need zoned air cooling. Some homes have both, as two systems with two surveys.
Two outdoor boxes, two jobs
Altherma moves heat into water. Splits move heat into air at an indoor unit. A quote that uses Altherma and Stylish on the same line without explaining both circuits is confused.
BUS grant rules for air-to-water and air-to-air differ. MCS applies to BUS. Do not assume a cooling split is an Altherma grant job.
- Write whether you need hot water, radiators, underfloor, or air cooling.
- Do not reuse an Altherma outdoor as a split outdoor.
- Ask how cooling mode works if the Altherma design claims it.
- Check outdoor space; two plants need two positions.
When Altherma is the right Daikin conversation
Boiler replacement, whole-home heat loss, a cylinder, and MCS-led funding. That is heating engineering. This site's local AC installers may or may not also be heat-pump MCS firms. Ask.
Read the air-to-air grant guide if your search was really about cooling that also heats a room.
When a split is the right conversation
Bedrooms, offices, shops, garden rooms, and any brief that starts with summer overheating. Altherma will not magically become a quiet bedroom head.
Use the Daikin installation and mini-split guides.
Having both
Some households keep Altherma for wet heat and add a split for a glass extension. That can be rational. It is two F-gas systems, two maintenance plans, two outdoor positions.
Design them together so they do not fight on controls or noise.
Frequently asked questions
Is Altherma an air conditioner?
It is an air-to-water heat pump. Some designs can cool water circuits. It is not a standard wall-mounted air conditioner.
Can Altherma replace my need for AC?
Only if the emitter system can deliver useful cooling in the rooms that overheat. Many radiator systems cannot. Survey both problems.
Which one gets the BUS grant?
Eligible air-to-water heat pumps and eligible air-to-air heat pumps have different grant amounts and tests. Read Ofgem's current rules. A comfort-cooling split is not automatically eligible.
Core buying guides
Start with these high-intent guides, then dig into the rest of the library.
Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.