iNHEAT 14kw Inverter Heat Source PumpThe Future of Hot Tub & Spa Heating! The iNHEAT 14. 5kW Inverter Heat Pump is perfect for heating Medium Swim Spas because it's 2. 66kW power in capacity and water flow of 6m per hour make it great for heating up a Medium Swim Spa 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