Smart finish in a brushed stainless steel exterior, the quality of the Isotemp Basic by Isotherm, is not just skin deep. Optimal water heating is achieved in two ways, firstly by an immersed electric heating element (immersion heater) and secondly by utilising the boat's engine water heat (Heat Exchange). Isotemp water heaters may be used with fresh water or salt water cooled engine systems. The immersion heater and heat exchanger are positioned in the lowest part of the tank, providing even thermo cycle heating of the water in the system. The engine water heat exchanger coil is extra long for faster heating, especially handy on sailing yachts, which may run their engine for short periods only. The water inlets and outlets are positioned to minimise mixing of cold water into the hot, by the incoming water.