Saz Boilers, a Pune based company manufactures heat recovery units for commercial and industrial sectors. This kind of system is required in businesses and industries in order to make the space more efficient by recovering heat. Through a ventilation system, roof mounted heat recovery unit works to draw heat from environment air and passes that heat to ingoing air. There is no need to connect the heat recovery unit with heating system in place. The unit has the efficiency to extract up to 90% heat from the outgoing air and passes the heat to the air that is circulating back into the unit. The buildings where heat recovery units need to be installed must be completely insulated.