Might be suggesting a HRV system. Speaking to a guy that supplies ventilation systems. he said the HRV is not efficient enough to warrant the cost. he said 1500 to 2000 for the HRV unit to slot into the overall unit. HE said they are alot more effective when the outside temperature is very low. For example Sweden places like that. I am putting in a ventialtion system looking at an air to air heat pump. Getting costings this week so price will determine whether i go with a heat pump.