We noted earlier that the air inside the home is more polluted than the air outside. So it makes sense that we would want to exchange the air inside with the air outside.
In older homes whose outer envelopes (exterior walls and roof) were not built very tight, this happens naturally via a myriad of small fissures in the exterior.
But in more tightly built modern homes, it is hard for the exterior air to infiltrate the interior. And this prevents air changes happening naturally.
We overcome this problem in three ways:
The first is to mimic the passive ventilation of the older home by installing vents in the exterior wall and under the eaves of the roof. Air will infiltrate naturally as driven by the wind or temperature differentials between the exterior and interior.
The second is to install a mechanical ventilation system in conjunction with the air conditioning system.
The third is to physically let the outside air in from time to time by opening your windows and doors. Do this from time to time even in the winter months. Same in the summer – but make sure there are screens on the windows
But, as for the first two options, we suggest that you talk to a local HVAC contractor for their recommendations