aroTHERM split

aroTHERM split is Vaillant’s refrigerant-split air-to-water heat pump. It uses an outdoor unit and a wall-mounted indoor module connected by R410A refrigerant pipework.

Five output classes

The current UK range has 3.5, 5, 7, 10 and 12 kW classes. The established codes use VWL 35/5, 55/5, 75/5, 105/5 and 125/5 outdoor families with matched VWL indoor units. All five use a 230 V supply.

Outdoor unit	Matched hydraulic indoor unit
VWL 35/5 AS	VWL 57/5 IS
VWL 55/5 AS	VWL 57/5 IS
VWL 75/5 AS	VWL 77/5 IS
VWL 105/5 AS	VWL 127/5 IS
VWL 125/5 AS	VWL 127/5 IS

The complete rating-plate suffix remains part of the unit identity; the current outdoor schedule uses 230 V S2 forms.

Manufacturer capacity classes do not replace the performance table. The design uses the exact combination’s output at the selected outdoor and flow-water temperatures.

Split-system boundaries

Refrigerant passes between the outdoor and indoor modules. That differs from aroTHERM plus, which contains R290 outdoors and connects hydraulically.

The indoor unit supplies heating water and can work with a compatible separate hot-water cylinder. sensoCOMFORT provides system control, while remote operation needs the myVAILLANT connect gateway and app. Those components form part of the system equipment schedule.

Certification and guarantee dates

Current aroTHERM split combinations were present in the MCS Product Directory on 23 July 2026. The five listed capacity classes had certification periods ending on 14 November 2026. Current status after that date comes from the exact Product Directory record.

The standard guarantee is two years, with a route up to seven years subject to eligible installation, registration and Vaillant-cylinder conditions.

Related entries

• Vaillant
• aroTHERM plus
• uniSTOR heat-pump cylinder
• Split air-source heat-pump units
• F-gas qualification rules