The iNHEAT 5.2kW heat source pump is perfect for heating Medium Hot Tubs because it's 0.95kW power in capacity and water volume of 20-25m3 make it great for heating up a medium hot tub quickly and efficiently! Use the heat pumps 3 different modes to get the best of our of your hot tub. Boost Mode heats your hot tub faster making it great for winter to late spring. Smart Mode uses the best output to give your the best heating and efficiency. Silent mode uses up to half capacity to keep it quiet.