The Worcester Bosch Greenstar 27Ri regular ErP boiler is a highly efficient, condensing boiler designed to save energy by recycling exhaust gases to extract and reuse latent heat. As one of the smallest condensing boilers available, it can even be installed within a standard kitchen cabinet. This boiler is designed for heating systems that include stored hot water in a cylinder and features a fascia-mounted heating temperature control knob and a neon operational status indicator.