Vaillant 5kw Arotherm Plus Air To Water Heat Pump (With Interface) 0010037212Vaillant aroTHERM plus heat pumps are extremely quiet, very efficient and charged with R290, a very low global warming potential (GWP refrigerant). The units have high temperature capability which is especially good when producing hot water meaning they do not use an immersion heater at all during pasteurisation cycles. We also sell Vaillant sensoCOMFORT controls, hydraulic module and Vaillant heat pump hot water cylinders and mounting accessories.