The "Ventless" option is a heat recovery condensation removal system that captures and distributes normally exhausted heat form the wash/rinse tank, using this FREE energy to pre-heat cold water prior to feeding the booster heater. Water entering the booster heater has been pre-heated, reducing the energy cost to bring booster temperature to required 180°, potentially saving thousands of dollars in operational costs. 12kW electrical booster heater. Booster-safety thermostat. 6kW wash tank heater.